Medicine › Radiology, Nuclear Medicine and Imaging

Corneal surgery and disorders

Works Count: 66838

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Description

This cluster of papers focuses on the biomechanical properties of the cornea, with a specific emphasis on conditions such as keratoconus and related treatments like collagen crosslinking. It also covers topics such as corneal transplantation, intraocular pressure measurement, and the impact of riboflavin-ultraviolet-A treatment. Additionally, it explores advancements in refractive surgery techniques and their effects on corneal biomechanics.

Keywords

Corneal Biomechanics; Keratoconus; Collagen Crosslinking; Corneal Transplantation; Ocular Response Analyzer; Endothelial Keratoplasty; Intraocular Pressure; Riboflavin-Ultraviolet-A Treatment; Corneal Thickness; Refractive Surgery

Influence of corneal biomechanical properties on intraocular pressure measurement

2005-01-01

Jun Liu , Cynthia J. Roberts

To understand and quantify intraocular pressure (IOP) measurement errors introduced by corneal variables during applanation tonometry using a cornea biomechanical model.Department of Ophthalmology, Biomedical Engineering Center, The Ohio State University, … To understand and quantify intraocular pressure (IOP) measurement errors introduced by corneal variables during applanation tonometry using a cornea biomechanical model.Department of Ophthalmology, Biomedical Engineering Center, The Ohio State University, Columbus, Ohio, USA.The model assumed an overall resultant pressure that was based on the summation of the applanation pressure, the true IOP, and the surface tension caused by the tear film to determine the final deformation of the corneal apex during IOP measurement. Corneal resistance was varied according to the cornea's biomechanical properties, thickness, and curvature, and the effect of each variable on the accuracy of IOP tonometry readings was examined quantitatively.The model demonstrated that tonometry readings do not always reflect true IOP values. They deviate when corneal thickness, curvature, or biomechanical properties vary from normal values. Based on the model, predicted IOP readings have a 2.87 mm Hg range resulting from the variation in the corneal thickness in the normal population and a 1.76 mm Hg range from the variation in the corneal radius of curvature. Considering that Young's modulus of the corneal varies from 0.1 to 0.9 MPa in the normal population, the model predicts tonometry IOP readings will have a range of 17.26 mm Hg because of the variation in this corneal biomechanical parameter alone.The simulation based on the model demonstrated quantitatively that variations in each corneal variable cause errors in tonometry IOP readings. The simulation results indicate that differences in corneal biomechanics across individuals may have greater impact on IOP measurement errors than corneal thickness or curvature.

Iatrogenic Keratectasia after Laser in situ Keratomileusis

1998-05-01

Theo Seiler , Konstantina Koufala , Gernot Richter

ABSTRACT BACKGROUND: Lamellar refractive surgery reduces the biomechanical strength of the cornea which may lead to mechanical instability and keratectasia. METHODS: Three eyes had laser in situ keratomileusis (LASIK) for … ABSTRACT BACKGROUND: Lamellar refractive surgery reduces the biomechanical strength of the cornea which may lead to mechanical instability and keratectasia. METHODS: Three eyes had laser in situ keratomileusis (LASIK) for myopia from -10.00 to -13.50 D. The procedures were performed with two different wide-field excimer lasers and two different microkeratomes. The patients were followed up to 1 year after surgery. RESULTS: Central steep areas developed between 1 and 8 months after surgery. In contrast to conventional central steep islands, these showed rapid progression and were interpreted as keratectasia. CONCLUSION: Iatrogenic keratectasia represents a complication after LASDX that may limit the range of myopia correction. Based on biomechanical considerations we recommend a residual corneal thickness of the stromal bed of at least 250 µm. [J Refract Surg 1998;14:312-317]

Descemet Membrane Endothelial Keratoplasty: Safety and Outcomes

2017-09-16

Sophie X. Deng , W. Barry Lee , K.M. Hammersmith +5 more

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Human Corneal Thickness and Its Impact on Intraocular Pressure Measures

2000-03-01

Michael J. Doughty , Mohammed L. Zaman

Corneal structure and transparency

2015-07-04

Keith M. Meek , Carlo Knupp

The corneal stroma plays several pivotal roles within the eye. Optically, it is the main refracting lens and thus has to combine almost perfect transmission of visible light with precise … The corneal stroma plays several pivotal roles within the eye. Optically, it is the main refracting lens and thus has to combine almost perfect transmission of visible light with precise shape, in order to focus incoming light. Furthermore, mechanically it has to be extremely tough to protect the inner contents of the eye. These functions are governed by its structure at all hierarchical levels. The basic principles of corneal structure and transparency have been known for some time, but in recent years X-ray scattering and other methods have revealed that the details of this structure are far more complex than previously thought and that the intricacy of the arrangement of the collagenous lamellae provides the shape and the mechanical properties of the tissue. At the molecular level, modern technologies and theoretical modelling have started to explain exactly how the collagen fibrils are arranged within the stromal lamellae and how proteoglycans maintain this ultrastructure. In this review we describe the current state of knowledge about the three-dimensional stromal architecture at the microscopic level, and about the control mechanisms at the nanoscopic level that lead to optical transparency.

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The three-dimensional organization of collagen fibrils in the human cornea and sclera.

1991-07-01

Yuki Komai , Tatsuo Ushiki

The organization of collagen fibrils in the human cornea and sclera was studied by scanning electron microscopy, after digestion of cellular elements by sodium hydroxide, and by conventional transmission electron … The organization of collagen fibrils in the human cornea and sclera was studied by scanning electron microscopy, after digestion of cellular elements by sodium hydroxide, and by conventional transmission electron microscopy. The collagen fibrils in the cornea had a uniform diameter of about 25 nm. In Bowman's layer, individual collagen fibrils were interwoven densely to form a felt-like sheet. In the stroma, most of the collagen fibrils ran abreast in lamellae, with varying widths and thickness. These lamellae were arranged basically parallel to the corneal surface but often communicated with those of adjacent layers by interchanging their fibrils. In the innermost stromal region adjacent to Descemet's membrane, collagen fibrils were oriented in various directions and interlaced, forming loose fibrillar networks. The sclera, however, was composed of collagen fibrils with various diameters ranging from 25-230 nm. Although these collagen fibrils formed bundles, they were not parallel but were entangled in individual bundles. These collagen bundles varied in width and thickness, often gave off branches, and intertwined with each other.

Refractive Development of the Human Eye

1985-06-01

Robert Gordon , Paul B. Donzis

• A complete refractive investigation was performed on 148 normal eyes of 79 patients ranging from premature newborns to 36-year-old adults. Cycloplegic refraction, keratometry, and axial length measurements were performed. … • A complete refractive investigation was performed on 148 normal eyes of 79 patients ranging from premature newborns to 36-year-old adults. Cycloplegic refraction, keratometry, and axial length measurements were performed. From these data, we then calculated the refractive power of the lens. The change with respect to age in these measurements was subjected to cross-sectional analysis. The full-term newborn eye had a mean axial length of 16.8 mm, a mean keratometric power of 51.2 diopters (spherical equivalent), and a mean lens power of 34.4 D. The adult values for these measurements were 23.6 mm, 43.5 D, and 18.8 D, respectively. This information concerning the expected change with age in the refractive components should aid in the refractive management of pediatric patients requiring cataract extraction.

Theory of Transparency of the Eye

1971-03-01

George B. Benedek

The present work relates the turbidity of the eye to microscopic spatial fluctuations in its index of refraction. Such fluctuations are indicated in electron microscope photographs. By examining the superposition … The present work relates the turbidity of the eye to microscopic spatial fluctuations in its index of refraction. Such fluctuations are indicated in electron microscope photographs. By examining the superposition of phases of waves scattered from each point in the medium, we provide a mathematical demonstration of the Bragg reflection principle which we have recently used in the interpretation of experimental investigations: namely, that the scattering of light is produced only by those fluctuations whose fourier components have a wavelength equal to or larger than one half the wavelength of light in the medium. This consideration is applied first to the scattering of light from collagen fibers in the normal cornea. We demonstrate physically and quantitatively that a limited correlation in the position of near neighbor collagen fibers leads to corneal transparency. Next, the theory is extended to predict the turbidity of swollen, pathologic corneas, wherein the normal distribution of collagen fibers is disturbed by the presence of numerous lakes-regions where collagen is absent. A quantitative expression for the turbidity of the swollen cornea is given in terms of the size and density of such lakes. Finally, the theory is applied to the case of the cataractous lens. We assume that the cataracts are produced by aggregation of the normal lens proteins into an albuminoid fraction and provide a formula for the lens turbidity in terms of the molecular weight and index of refraction of the individual albuminoid macromolecules. We provide a crude estimate of the mean albuminoid molecular weight required for lens opacity.

A Surgical Technique for Posterior Lamellar Keratoplasty

1998-11-01

Gerrit R.J. Melles , Fred A.G.J. Eggink , Frank Lander +4 more

Purpose To design a surgical technique for transplantation of posterior corneal tissue, while leaving the recipient anterior cornea intact. Methods In human cadaver eyes, and in a cat and monkey … Purpose To design a surgical technique for transplantation of posterior corneal tissue, while leaving the recipient anterior cornea intact. Methods In human cadaver eyes, and in a cat and monkey model, recipient eyes had an 8.0-mm limbal incision made with a diamond blade set to 50% of central pachymetry. A stromal pocket was created across the cornea, and a 6.0-mm diameter posterior lamellar disc was excised. A donor posterior disc was implanted into the recipient opening, and the limbal incision was sutured. The procedure was evaluated with keratometry, biomicroscopy, endothelial (supra)vital staining, and light microscopy. Results In human cadaver eyes, postoperative astigmatism averaged 1.2 D (SD, ±0.6 D). Posterior transplants showed an intact endothelial cell layer with 1.0% (SD, ±1.2%) of cell death. In the animals, six (75%) eyes had clear transplants 2 weeks after surgery; one of these eyes later developed an allograft rejection. Two (25%) eyes showed corneal decompensation, because of inverted implantation of the donor disc. Microscopy showed minimal scarring at the donor-to-host interface and a normal wound-healing response at the posterior stromal wound edges. Conclusion In experimental models, posterior lamellar keratoplasty can be performed through a limbal incision and a mid-stromal pocket. The procedure may be a potential alternative in the surgical management of corneal endothelial disorders.

A Randomized, Controlled Trial of Corneal Collagen Cross-Linking in Progressive Keratoconus

2014-01-06

Christine Wittig-Silva , Elsie Chan , Amirul Islam +3 more

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Crosslinking treatment of progressive keratoconus: new hope

2006-07-11

Gregor Wollensak

A new method has been introduced for the treatment of progressive keratoconus using collagen crosslinking by the photosensitzer riboflavin and ultraviolet A-light. Biomechanical measurements have shown an impressive increase in … A new method has been introduced for the treatment of progressive keratoconus using collagen crosslinking by the photosensitzer riboflavin and ultraviolet A-light. Biomechanical measurements have shown an impressive increase in corneal rigidity of 328.9% in human corneas after crosslinking.The 3 and 5-year results of the Dresden clinical study have shown that in all treated 60 eyes the progression of keratoconus was at least stopped ('freezing'). In 31 eyes there also was a slight reversal and flattening of the keratoconus by up to 2.87 diopters. Best corrected visual acuity improved slightly by 1.4 lines. So far, over 150 keratoconus patients have received crosslinking treatment in Dresden. Laboratory studies have revealed that the maximum effect of the treatment is in the anterior 300 mum of the cornea. As for the corneal endothelium, a cytotoxic level for endothelium was found to be 0.36 mW/cm which would be reached in human corneas with a stromal thickness of less than 400 mum.Collagen crosslinking by the photosensitzer riboflavin and ultraviolet A-light is an effective means for stabilizing the cornea in keratoconus. Collagen crosslinking might become the standard therapy for progressive keratoconus in the future diminishing significantly the need for corneal transplantation. Preoperative pachymetry and individual control of the ultraviolet A-irradiance before each treatment are mandatory. The treatment parameters must not be varied.

Central corneal thickness in the ocular hypertension treatment study (OHTS)

2001-10-01

James D. Brandt , Julia A. Beiser , Michael A. Kass +1 more

Risk Assessment for Ectasia after Corneal Refractive Surgery

2007-07-13

J. Bradley Randleman , Maria A. Woodward , Michael Lynn +1 more

Descemet-Stripping Automated Endothelial Keratoplasty

2006-09-01

Mark S. Gorovoy

To evaluate the speed of visual recovery in 16 consecutive patients with corneal endothelial dysfunction who received Descemet-stripping automated endothelial keratoplasty (DSAEK).This is a retrospective study of a novel method … To evaluate the speed of visual recovery in 16 consecutive patients with corneal endothelial dysfunction who received Descemet-stripping automated endothelial keratoplasty (DSAEK).This is a retrospective study of a novel method for small-incision endothelial transplantation (DSAEK). Endothelial replacement was accomplished with Descemet stripping of the recipient and insertion of a posterior donor tissue that had been prepared with a microkeratome. Best spectacle-corrected visual acuity (BSCVA) by manifest refraction, endothelial counts, and dislocation rates were measured up to 12 months after DSAEK.Sixteen consecutive patients underwent uncomplicated DSAEK. Three patients had known optic nerve or macular disease precluding vision better than 20/200. Of the remaining 14 patients, 11 had BSCVA of 20/40 by postoperative week 12 (7 by week 6). The remaining 2 were 20/50 by weeks 6 and 12. All 14 patients were 20/40 or better at 1 year. One patient had a primary graft failure, and surgery was repeated with 20/40 BSCVA at 1 year. The dislocation rate was 25%. The average cell count between 7 and 10 months was 1714. The average pachymetry was 682.DSAEK surgery allows rapid, excellent BSCVA visual recovery. The rate of visual recovery is more rapid than usually found with penetrating keratoplasty.

Safety of UVA-Riboflavin Cross-Linking of the Cornea

2007-04-02

Eberhard Spoerl , Michael Mrochen , David H. Sliney +2 more

To study potential damage to ocular tissue during corneal collagen cross-linking (X-linking) by means of the riboflavin/UVA (370 nm) approach.Comparison of the currently used technique with officially accepted guidelines regarding … To study potential damage to ocular tissue during corneal collagen cross-linking (X-linking) by means of the riboflavin/UVA (370 nm) approach.Comparison of the currently used technique with officially accepted guidelines regarding direct UV damage and the damage created by the induced free radicals (photochemical damage).The currently used UVA radiant exposure of 5.4 mJ/cm and the corresponding irradiance of 3 mW/cm2 is below the known damage thresholds of UVA for the corneal endothelium, lens, and retina. Regarding the photochemical damage caused by the free radicals, the damage thresholds for keratocytes and endothelial cells are 0.45 and 0.35 mW/cm, respectively. In a 400-microm-thick cornea saturated with riboflavin, the irradiance at the endothelial level was 0.18 mW/cm, which is a factor of 2 smaller than the damage threshold.After corneal X-linking, the stroma is depopulated of keratocytes approximately 300 microm deep. Repopulation of this area takes up to 6 months. As long as the cornea treated has a minimum thickness of 400 microm (as recommended), the corneal endothelium will not experience damage, nor will deeper structures such as lens and retina. The light source should provide a homogenous irradiance, avoiding hot spots.

Keratoconus and related noninflammatory corneal thinning disorders

1984-01-01

Jay H. Krachmer , Robert S. Feder , Michael W. Belin

Big-bubble technique to bare Descemet's membrane in anterior lamellar keratoplasty

2002-03-01

Mohammed Anwar , Klaus D. Teichmann

We describe a lamellar keratoplasty technique to bare Descemet's membrane in which air is injected to detach the central Descemet's. After a partial-thickness corneal trephination is performed, a disposable needle … We describe a lamellar keratoplasty technique to bare Descemet's membrane in which air is injected to detach the central Descemet's. After a partial-thickness corneal trephination is performed, a disposable needle is inserted, deeply and bevel down, into the paracentral corneal stroma and air is injected. In most cases, this forms a large air bubble between Descemet's membrane and the corneal stroma. After anterior lamellar keratectomy is performed, a small opening is made in the air bubble and the remaining stromal layers are lifted with an iris spatula, severed with a blade, and excised with scissors. This technique is faster, safer, and easier to perform than previous methods.

Descemet's Membrane Endothelial Keratoplasty

2009-10-29

Marianne O. Price , Arthur W. Giebel , Kelly M. Fairchild +1 more

Long-term graft survival after penetrating keratoplasty

2003-07-01

Robert W. Thompson , Marianne O. Price , Patrick Bowers +1 more

Long-term Results of Riboflavin Ultraviolet A Corneal Collagen Cross-linking for Keratoconus in Italy: The Siena Eye Cross Study

2010-02-09

Aldo Caporossi , Cosimo Mazzotta , Stefano Baiocchi +1 more

Wound Healing After Excimer Laser Keratomileusis (Photorefractive Keratectomy) in Monkeys

1990-05-01

Francisco Fantes

Laser myopic keratomileusis (photorefractive keratectomy) was performed on 29 rhesus monkey corneas with an argon fluoride (193-nm) excimer laser and a computer-controlled, moving slit delivery system. The 4-mm-diameter central ablation … Laser myopic keratomileusis (photorefractive keratectomy) was performed on 29 rhesus monkey corneas with an argon fluoride (193-nm) excimer laser and a computer-controlled, moving slit delivery system. The 4-mm-diameter central ablation zone ranged in depth from 11 microns (-2 diopters effect) to 46 microns (-8 diopters effect). Corneas were studied for the 9 months postoperatively by clinical slit-lamp microscopy, and periodically with light and transmission electron microscopy. By 6 weeks, mild to moderate subepithelial haze was apparent in 93% of the corneas, with considerable variability in density. Progressive clearing occurred so that by 6 to 9 months 12 of 13 surviving corneas (92%) were either completely clear (4 corneas) or trace hazy (8 corneas). The epithelium was thickened at 21 days after ablation and returned to normal thickness by 3 months. At 3 weeks, subepithelial fibroblasts were three times the density of normal keratocytes and returned to nearly normal numbers by 9 months. We concluded that the anterior monkey cornea demonstrated a mild, typical wound healing response after excimer laser keratomileusis.

Global Consensus on Keratoconus and Ectatic Diseases

2015-03-04

José Álvaro Pereira Gomes , Donald Tan , Christopher J. Rapuano +6 more

Background: Despite extensive knowledge regarding the diagnosis and management of keratoconus and ectatic corneal diseases, many controversies still exist. For that reason, there is a need for current guidelines for … Background: Despite extensive knowledge regarding the diagnosis and management of keratoconus and ectatic corneal diseases, many controversies still exist. For that reason, there is a need for current guidelines for the diagnosis and management of these conditions. Purpose: This project aimed to reach consensus of ophthalmology experts from around the world regarding keratoconus and ectatic diseases, focusing on their definition, concepts, clinical management, and surgical treatments. Methods: The Delphi method was followed with 3 questionnaire rounds and was complemented with a face-to-face meeting. Thirty-six panelists were involved and allocated to 1 of 3 panels: definition/diagnosis, nonsurgical management, or surgical treatment. The level of agreement considered for consensus was two thirds. Results: Numerous agreements were generated in definitions, methods of diagnosing, and management of keratoconus and other ectatic diseases. Nonsurgical and surgical treatments for these conditions, including the use of corneal cross-linking and corneal transplantations, were presented in a stepwise approach. A flowchart describing a logical management sequence for keratoconus was created. Conclusions: This project resulted in definitions, statements, and recommendations for the diagnosis and management of keratoconus and other ectatic diseases. It also provides an insight into the current worldwide treatment of these conditions.

The Vertebrate Eye and Its Adaptive Radiation

1943-04-17

Gordon Lynn. Walls

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor … Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal

Induction of Cross-links in Corneal Tissue

1998-01-01

Eberhard Spoerl , M. Huhle , Theo Seiler

APPLANATION TONOMETRY AND CENTRAL CORNEAL THICKNESS

1975-03-01

Niels Ehlers , Thorkild Bramsen , STEFFEN SPERLING

Readings with the Goldmann applanation tonometer were made at various intraocular hydrostatic pressures and compared with central corneal thickness and radius in rabbit and in man. Linear correlations were established … Readings with the Goldmann applanation tonometer were made at various intraocular hydrostatic pressures and compared with central corneal thickness and radius in rabbit and in man. Linear correlations were established between hydrostatic pressure and applanation readings, with correlation coefficients close to 1.0. In rabbits the tonometer readings were generally too low. In human eyes with a normal corneal thickness tonometer readings and hydrostatic pressure coincided, with thick corneas the readings were too high, with thin corneas too low. The correlation between corneal thickness and the error of applanation tonometry (ΔP) was statistically highly significant (P < 0.001). No statistical correlation could be established between corneal radius and ΔP. Multiple regression, taking thickness as well as corneal radius into consideration, revealed only slightly higher correlation coefficients. It is concluded that the central corneal thickness is a parameter which should be taken into consideration when evaluating applanation tonometer readings. A Table is presented showing the correction to be added to the applanation reading at differing corneal thickness.

A 48-Year Clinical and Epidemiologic Study of Keratoconus

1986-03-01

Robert H. Kennedy , William M. Bourne , John A. Dyer

Accommodation, refractive error and eye growth in chickens

1988-01-01

Frank Schaeffel , Adrian Glasser , Howard C. Howland

Photorefractive keratectomy: A technique for laser refractive surgery

1988-01-01

Charles R. Munnerlyn , Stephen J. Koons , John Marshall

The excimer laser offers entirely new corneal surgery procedures. In this paper, we describe conditions for one such procedure, photorefractive keratectomy, the direct reshaping of the cornea's central optical zone … The excimer laser offers entirely new corneal surgery procedures. In this paper, we describe conditions for one such procedure, photorefractive keratectomy, the direct reshaping of the cornea's central optical zone using tissue ablation with far ultraviolet radiation. We present equations for the required tissue ablation to achieve required refractive corrections. Conditions for beam uniformity are presented and a method of achieving better beam uniformity using beam integration by rotation is demonstrated. The healing of rabbit corneas after area ablation was observed. Five days after treatment, the surface quality of deep cuts was very irregular; the shallow cuts produced more regular results, as predicted by our calculations of beam characteristics.

Sources of error with use of Goldmann-type tonometers

1993-07-01

Marc M. Whitacre , Richard A. Stein

The corneal endothelium. Normal and pathologic structure and function.

1982-06-01

George O. Waring , William M. Bourne , Henry F. Edelhauser +1 more

Determining in vivo biomechanical properties of the cornea with an ocular response analyzer

2005-01-01

David A. Luce

In Brief Purpose: To study the results of an ocular response analyzer (ORA) to determine the biomechanical properties of the cornea and their relationship to intraocular pressure (IOP). Setting: Reichert … In Brief Purpose: To study the results of an ocular response analyzer (ORA) to determine the biomechanical properties of the cornea and their relationship to intraocular pressure (IOP). Setting: Reichert Inc., Depew, New York, USA. Methods: The ORA (Reichert) makes 2 essentially instantaneous applanation measurements that permit determination of corneal and IOP effects. Results: Measurements of several populations indicate that corneal hysteresis, a biomechanical measure, varied over a dynamic range of 1.8 to 14.6 mm Hg and was only weakly correlated with corneal thickness (r2 = 0.12); this is related to the observation that some subjects with relatively thick corneas have less-than-average corneal hysteresis. Corneal hysteresis changes diurnally, presumably as a result of hydration changes. Keratoconus, Fuchs' dystrophy, and post-LASIK patients demonstrated low corneal hysteresis. Conclusion: The corneal hysteresis biomechanical measure may prove valuable for qualification and predictions of outcomes of refractive surgery and in other cases in which corneal biomechanics are important. The ocular response analyzer determines biomechanical properties of the cornea and the IOP by making 2 essentially instantaneous applanation measurements that permit determination of corneal and pressure effects. Measurements indicate that a new corneal biomechanical measure called corneal hysteresis varies over a dynamic range and is only weakly correlated with corneal thickness.

Central corneal endothelial cell changes over a ten-year period.

1997-08-01

LR Nelson , DO Hodge , W. M. Bourne

The Effect of Corneal Thickness on Applanation Tonometry

1993-05-01

Marc M. Whitacre , Richard A. Stein , Khatab M. Hassanein

Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study

2010-07-03

Walter Sekundo , Kathleen S. Kunert , Marcus Blum

<h3>Aim</h3> This 6 month prospective multi-centre study evaluated the feasibility of performing myopic femtosecond lenticule extraction (FLEx) through a small incision using the small incision lenticule extraction (SMILE) procedure. <h3>Design</h3> … <h3>Aim</h3> This 6 month prospective multi-centre study evaluated the feasibility of performing myopic femtosecond lenticule extraction (FLEx) through a small incision using the small incision lenticule extraction (SMILE) procedure. <h3>Design</h3> Prospective, non-randomised clinical trial. <h3>Participants</h3> Ninety-one eyes of 48 patients with myopia with and without astigmatism completed the final 6 month follow-up. The patients9 mean age was 35.3 years. Their preoperative mean spherical equivalent (SE) was −4.75±1.56 D. <h3>Methods</h3> A refractive lenticule of intrastromal corneal tissue was cut utilising a prototype of the Carl Zeiss Meditec AG VisuMax femtosecond laser system. Simultaneously two opposite small ‘pocket’ incisions were created by the laser system. Thereafter, the lenticule was manually dissected with a spatula and removed through one of incisions using modified McPherson forceps. <h3>Main outcome measures</h3> Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) after 6 months, objective and manifest refraction as well as slit-lamp examination, side effects and a questionnaire. <h3>Results</h3> Six months postoperatively the mean SE was −0.01 D±0.49 D. Most treated eyes (95.6%) were within ±1.0 D, and 80.2% were within ±0.5 D of intended correction. Of the eyes treated, 83.5% had an UCVA of 1.0 (20/20) or better, 53% remained unchanged, 32.3% gained one line, 3.3% gained two lines of BSCVA, 8.8% lost one line and 1.1% lost ≥2 lines of BSCVA. When answering a standardised questionnaire, 93.3% of patients were satisfied with the results obtained and would undergo the procedure again. <h3>Conclusion</h3> SMILE is a promising new flapless minimally invasive refractive procedure to correct myopia.

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Laser in situ keratomileusis

1990-01-01

loannis G Pallikaris , Maria E. Papatzanaki , Evdoxia Z. Stathi +2 more

Abstract A new laser refractive procedure is being developed in a rabbit model. With a modified microkeratome, central corneal flaps were created. An ArF excimer laser was used to produce … Abstract A new laser refractive procedure is being developed in a rabbit model. With a modified microkeratome, central corneal flaps were created. An ArF excimer laser was used to produce 3‐mm‐diameter circular ablations on the central part of the exposed stromal bed. One group of animals was sacrificed immediately postoperatively, and both the dissected and ablated areas were studied using scanning electron microscopy. A second group of animals was sacrificed 4 weeks postoperatively. In this group, the subsequent healing of the corneas was studied using light microscopy. At 3 days, the wounded stromal areas showed some degree of haze. Haze was progressively reduced over 1 month, but it could be still discerned biomicroscopically. A hemicircular opacification corresponding to the flap edges was also apparent on slit‐lamp examination. Microscopic observation showed that the epithelium was normal, except at the flap margins, where it was thickened. An increased number of keratocytes was observed in the interface between the flap stroma and the ablated area. The procedure might induce stable corneal changes because of the preservation of the anterior layers of the cornea.

Excimer Laser Surgery of the Cornea

1983-12-01

Stephen L. Trokel , R. Srinivasan , Bodil Braren

Riboflavin/ultraviolet-a–induced collagen crosslinking for the treatment of keratoconus

2003-04-30

Gregor Wollensak , Eberhard Spoerl , Theo Seiler

Keratoconus: A review

2010-06-08

Miguel Romero-Jiménez , Jacinto Santodomingo‐Rubido , James S. Wolffsohn

Monochromatic aberrations of the human eye in a large population

2001-08-01

Jason Porter , Antonio Guirao , Ian Cox +1 more

From both a fundamental and a clinical point of view, it is necessary to know the distribution of the eye's aberrations in the normal population and to be able to … From both a fundamental and a clinical point of view, it is necessary to know the distribution of the eye's aberrations in the normal population and to be able to describe them as efficiently as possible. We used a modified Hartmann-Shack wave-front sensor to measure the monochromatic wave aberration of both eyes for 109 normal human subjects across a 5.7-mm pupil. We analyzed the distribution of the eye's aberrations in the population and found that most Zernike modes are relatively uncorrelated with each other across the population. A principal components analysis was applied to our wave-aberration measurements with the resulting principal components providing only a slightly more compact description of the population data than Zernike modes. This indicates that Zernike modes are efficient basis functions for describing the eye's wave aberration. Even though there appears to be a random variation in the eye's aberrations from subject to subject, many aberrations in the left eye were found to be significantly correlated with their counterparts in the right eye.

Stress-strain measurements of human and porcine corneas after riboflavin–ultraviolet-A-induced cross-linking

2003-09-01

Gregor Wollensak , Eberhard Spoerl , Theo Seiler

To evaluate the biomechanical effect of combined riboflavin-ultraviolet A (UVA) treatment on porcine and human corneas.Department of Ophthalmology, Technical University of Dresden, Dresden, Germany.Corneal strips from 5 human enucleated eyes … To evaluate the biomechanical effect of combined riboflavin-ultraviolet A (UVA) treatment on porcine and human corneas.Department of Ophthalmology, Technical University of Dresden, Dresden, Germany.Corneal strips from 5 human enucleated eyes and 20 porcine cadaver corneas were treated with the photosensitizer riboflavin and irradiated with 2 double UVA diodes (370 nm, irradiance = 3 mW/cm2) for 30 minutes. After cross-linking, static stress-strain measurements of the treated and untreated corneas were performed using a microcomputer-controlled biomaterial tester with a prestress of 5 x 10(3) Pa.There was a significant increase in corneal rigidity after cross-linking, indicated by a rise in stress in treated porcine corneas (by 71.9%) and human corneas (by 328.9%) and in Young's modulus by the factor 1.8 in porcine corneas and 4.5 in human corneas. The mean central corneal thickness was 850 microm +/- 70 (SD) in porcine corneas and 550 +/- 40 microm in human corneas.Riboflavin-UVA-induced collagen cross-linking led to an increase in mechanical rigidity in porcine corneas and an even greater increase in human corneas. As collagen cross-linking is maximal in the anterior 300 microm of the cornea, the greater stiffening effect in human corneas can be explained by the relatively larger portion of the cornea being cross-linked in the overall thinner human cornea.

Increased resistance of crosslinked cornea against enzymatic digestion

2004-01-01

Eberhard Spoerl , Gregor Wollensak , Theo Seiler

Collagen-crosslinking using combined riboflavin/ UVA treatment has been developed by us as a new treatment for keratoconus by stiffening the collagenous matrix. Recently, we have started to use the same … Collagen-crosslinking using combined riboflavin/ UVA treatment has been developed by us as a new treatment for keratoconus by stiffening the collagenous matrix. Recently, we have started to use the same method for the treatment of corneal ulcers. The aim of the present study was to evaluate the influence of the crosslinking treatment on the resistance of the cornea against enzymatic degradation.60 enucleated porcine eyes were treated with the photosensitizer riboflavin and UVA-irradiation (370 nm; irradiance of 1, 2 or 3 mW/cm2) for 30 minutes and compared with 20 untreated control eyes. After crosslinking treatment, the corneal buttons were trephined and exposed to pepsin, trypsin and collagenase solutions. The extent of the corneal digestion was monitored daily. Selected cases were examined by light microscopy.The corneal buttons crosslinked with riboflavin/ UVA at 3 mW/cm2 were dissolved only by day 13 following pepsin digestion and by day 14 following collagenase treatment versus 6 days in the untreated control corneas. Digestion by trypsin was observed on day 5 in buttons crosslinked at 3 mW/cm2 compared to day 2 in the control corneas. Microscopically, a prolonged preservation especially of the anterior portion of the crosslinked corneas could be demonstrated.Photochemical crosslinking of the cornea using riboflavin and UVA results in a markedly increased resistance versus collagen digesting enzymes. The findings support the use of the new method in the treatment of corneal ulcers.

Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: Long-term results

2008-05-01

F Raiskup-Wolf , A. Hoyer , Eberhard Spoerl +1 more

PURPOSE: To prove the long-term dampening effect of riboflavin- and ultraviolet-A-induced collagen crosslinking on progressive keratoconus. SETTING: Department of Ophthalmology, C.G. Carus University Hospital, Dresden, Germany. METHODS: Four hundred eighty … PURPOSE: To prove the long-term dampening effect of riboflavin- and ultraviolet-A-induced collagen crosslinking on progressive keratoconus. SETTING: Department of Ophthalmology, C.G. Carus University Hospital, Dresden, Germany. METHODS: Four hundred eighty eyes of 272 patients with progressive keratoconus were included in this long-term retrospective study. The maximum follow-up was 6 years. At the first and all follow-up examinations, refraction, best corrected visual acuity (BCVA), corneal topography, corneal thickness, and intraocular pressure were recorded. RESULTS: The analysis included 241 eyes with a minimum follow-up of 6 months. The steepening decreased significantly by 2.68 diopters (D) in the first year, 2.21 D in the second year, and 4.84 D in the third year. The BCVA improved significantly (≥1 line) in 53% of 142 eyes in the first year, 57% of 66 eyes in the second year, and 58% of 33 eyes in the first year or remained stable (no lines lost) in 20%, 24%, and 29%, respectively. Two patients had continuous progression of keratoconus and had repeat crosslinking procedures. CONCLUSIONS: Despite the low number of patients with a follow-up longer than 3 years, results indicate long-term stabilization and improvement after collagen crosslinking. Thus, collagen crosslinking is an effective therapeutical option for progressive keratoconus.

Global Survey of Corneal Transplantation and Eye Banking

2015-12-03

Philippe Gain , R. Jullienne , Zhiguo Hé +4 more

Corneal transplantation restores visual function when visual impairment caused by a corneal disease becomes too severe. It is considered the world's most frequent type of transplantation, but, to our knowledge, … Corneal transplantation restores visual function when visual impairment caused by a corneal disease becomes too severe. It is considered the world's most frequent type of transplantation, but, to our knowledge, there are no exhaustive data allowing measurement of supply and demand, although such data are essential in defining local, national, and global strategies to fight corneal blindness.To describe the worldwide situation of corneal transplantation supply and demand.Data were collected between August 2012 and August 2013 from a systematic review of published literature in parallel with national and international reports on corneal transplantation and eye banking. In a second step, eye bank staff and/or corneal surgeons were interviewed on their local activities. Interviews were performed during international ophthalmology or eye-banking congresses or by telephone or email. Countries' national supply/demand status was classified using a 7-grade system. Data were collected from 148 countries.Corneal transplantation and corneal procurements per capita in each country.In 2012, we identified 184,576 corneal transplants performed in 116 countries. These were procured from 283,530 corneas and stored in 742 eye banks. The top indications were Fuchs dystrophy (39% of all corneal transplants performed), a primary corneal edema mostly affecting elderly individuals; keratoconus (27%), a corneal disease that slowly deforms the cornea in young people; and sequellae of infectious keratitis (20%). The United States, with 199.10-6 corneal transplants per capita, had the highest transplantation rate, followed by Lebanon (122.10-6) and Canada (117.10-6), while the median of the 116 transplanting countries was 19.10-6. Corneas were procured in only 82 countries. Only the United States and Sri Lanka exported large numbers of donor corneas. About 53% of the world's population had no access to corneal transplantation.Our survey globally quantified the considerable shortage of corneal graft tissue, with only 1 cornea available for 70 needed. Efforts to encourage cornea donation must continue in all countries, but it is also essential to develop alternative and/or complementary solutions, such as corneal bioengineering.

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Alkali-Induced Corneal Neovascularization Is Independent of CXCR2-Mediated Neutrophil Infiltration

2006-11-13

Peirong Lu , Longbiao Li , Naofumi Mukaida +1 more

To study the role of infiltrating neutrophils in the development of experimental corneal neovascularization (CNV).CNV was induced by alkali injury in normal C57BL/6 mice, and the kinetics of neutrophil recruitment … To study the role of infiltrating neutrophils in the development of experimental corneal neovascularization (CNV).CNV was induced by alkali injury in normal C57BL/6 mice, and the kinetics of neutrophil recruitment to the cornea and the CNV was detected by histologic analysis at multiple time points. Neutrophil recruitment to the corneas was inhibited by injection of anti-mouse granulocyte monoclonal antibodies (Ly-6G) or neutralizing anti-mouse CXCR2 antibodies. CNV was compared between the control and the specific antibody-treated mice 2 weeks after alkali injury, as quantified by CD31 immunostaining. Corneal vascular endothelial growth factor (VEGF) expression after injury was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining.Many myeloperoxidase-positive neutrophils began to infiltrate the corneas 2 days after injury, but infiltration ceased by 14 days after injury. CNV became evident 7 days after injury, reached a maximal level at 14 days, and decreased thereafter. The mRNA expression of CXCR2 and its ligands, macrophage inflammatory protein 2 (CXCL2/MIP-2), and growth-related protein alpha (CXCL1/KC) increased markedly at 2 days after injury. Injection of either anti-mouse granulocyte monoclonal antibodies (Ly-6G) or neutralizing anti-mouse CXCR2 antibodies markedly, and to a similar extent, inhibited neutrophil recruitment to the cornea, indicating that neutrophil infiltration was mediated primarily by CXCR2. In contrast, these treatments failed to attenuate alkali-induced CNV. VEGF mRNA expression was enhanced 2 days after injury, and VEGF proteins were detected mainly in infiltrating mononuclear cells but not in neutrophils.CXCR2-mediated neutrophil infiltration contributes only marginally to the subsequent development of CNV.

The Vertebrate Eye and Its Adaptive Radiation

1943-03-31

Daniel Merriman , Gordon L. Walls

A Follow-up Study

1990-04-01

Charles M. Zacks , Richard L. Abbott , Max Fine

In 1983, Abbott et al. assessed endothelial cell population and function in 100 clear corneal grafts (72 patients) that were an average of 17.4 years postkeratoplasty. The present study reports … In 1983, Abbott et al. assessed endothelial cell population and function in 100 clear corneal grafts (72 patients) that were an average of 17.4 years postkeratoplasty. The present study reports on 61 of these grafts (42 patients) followed for an additional 4-6 years. Forty-nine grafts without intercurrent complications or surgery were reexamined by specular microscopy to determine the change in endothelial population in each graft. In 10 others, the reasons for regrafting were recorded. In two cases of hereditary stromal dystrophy, stromal opacity precluded a cell count. Of the grafts studied, 49 (80%) remained clear despite a depleted and slowly decreasing endothelial population. The rate of change was independent of donor age, preoperative diagnosis, or graft longevity. Two grafts failed spontaneously, and all three grafts that had cataract surgery failed in the early postoperative period. The remaining five were regrafted to correct high astigmatism or other complications. We conclude that despite a small degree of continuous cell loss, corneal grafts have a favorable prognosis for long-term clinical stability. The remaining endothelium has a minimal functional reserve, however, resulting in a high risk of graft decompensation after additional endothelial trauma.

Descemet's Stripping With Endothelial Keratoplasty in 50 Eyes: A Refractive Neutral Corneal Transplant

2005-07-01

Francis W. Price , Marianne O. Price

ABSTRACT PURPOSE: To evaluate early visual and refractive outcomes following treatment of corneal endothelial dysfunction with a corneal transplantation technique, Descemet's stripping with endothelial keratoplasty (DSEK). METHODS: Visual and refractive … ABSTRACT PURPOSE: To evaluate early visual and refractive outcomes following treatment of corneal endothelial dysfunction with a corneal transplantation technique, Descemet's stripping with endothelial keratoplasty (DSEK). METHODS: Visual and refractive outcomes of the first 50 consecutive cases of DSEK performed by a single surgeon between December 2003 and July 2004 were analyzed retrospectively. The DSEK technique consisted of stripping Descemet's membrane and endothelium from a recipient cornea and transplanting the posterior stroma and endothelium of a donor cornea through a 5-mm incision. RESULTS: Results are reported for 50 eyes in 47 patients (30 women and 17 men). Mean patient age at surgery was 70±12 years (range: 34 to 89 years). Five eyes were treated for corneal edema or bullous keratopathy and 45 for Fuchs' endothelial dystrophy. Seven eyes were phakic and 43 were Pseudophakic. Six months after surgery, mean manifest cylinder was 1.5±0.94 diopters (D), unchanged from preoperative cylinder of 1.5±1.0 D. Mean manifest spherical equivalent refraction was 0.15 ±1.5 D at 6-month follow-up compared with -0.36±1.4 D preoperatively (P=.10) At 3- and 6-month follow-up, significant improvement was noted in mean best spectacle-corrected visual acuity compared with the preoperative mean of 20/100 (P=.007). At 6-month follow-up, 31 (62%) eyes refracted to ≥20/40 and 38 (76%) eyes saw ≥20/50. CONCLUSIONS: Compared to standard penetrating keratoplasty, DSEK causes minimal refractive change and provides rapid visual recovery for patients with endothelial dysfunction. This technique maintains the structural integrity of the cornea by preserving the recipient's epithelium, Bowman's layer, and entire stromal thickness. [J Refract Surg. 2005;21:339-345.]

Proteoglycan-fibrillar collagen interactions

1988-06-01

J. E. Scott

Research Article| June 01 1988 Proteoglycan-fibrillar collagen interactions J E Scott J E Scott Chemical Morphology, Chemistry Building, Manchester University, Brunswick Street, Manchester M13 9PL, U.K. Search for other works … Research Article| June 01 1988 Proteoglycan-fibrillar collagen interactions J E Scott J E Scott Chemical Morphology, Chemistry Building, Manchester University, Brunswick Street, Manchester M13 9PL, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem J (1988) 252 (2): 313–323. https://doi.org/10.1042/bj2520313 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation J E Scott; Proteoglycan-fibrillar collagen interactions. Biochem J 1 June 1988; 252 (2): 313–323. doi: https://doi.org/10.1042/bj2520313 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Journal Search Advanced Search This content is only available as a PDF. © 1988 London: The Biochemical Society1988 Article PDF first page preview Close Modal You do not currently have access to this content.

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Keratoconus

1998-01-01

Yaron S. Rabinowitz

Descemet's stripping with endothelial keratoplasty in 200 eyes

2006-03-01

Francis W. Price , Marianne O. Price

PURPOSE: To describe early challenges and techniques to promote donor tissue adherence in Descemet's stripping with endothelial keratoplasty (DSEK). SETTING: Price Vision Group, Indianapolis, Indiana, USA. METHODS: The first 200 … PURPOSE: To describe early challenges and techniques to promote donor tissue adherence in Descemet's stripping with endothelial keratoplasty (DSEK). SETTING: Price Vision Group, Indianapolis, Indiana, USA. METHODS: The first 200 consecutive cases of DSEK performed by a single surgeon were analyzed retrospectively. Follow-up was 7 to 20 months for 124 eyes and 2 to 6 months for 76 eyes. The surgical technique consisted of stripping Descemet's membrane and endothelium from the recipient's central cornea and transplanting an 8.0 to 9.0 mm disc of donor endothelium and posterior stroma through a 5.0 mm incision, with sutures used only to close the incision. RESULTS: The most frequent challenge was inadequate donor attachment. Using techniques to remove fluid from the donor–recipient graft interface, the donor detachment rate in the last 64 cases was 6%, with half attributable to patient eye rubbing. Detached grafts were reattached by injecting an air bubble to press the donor against the recipient cornea. There were 7 primary graft failures, with only 1 occurring in the second 100 cases, which primarily used microkeratome-dissected donor tissue. Other complications were infrequent and included pupillary block glaucoma (1), aqueous misdirection syndrome (1), and cataract development in 2 of 27 phakic eyes. The DSEK procedure was performed safely before and after laser in situ keratomileusis (1 each). CONCLUSIONS: Early outcomes in the initial 200 consecutive DSEK procedures suggest the technique provides significant advantages over penetrating keratoplasty, including more rapid healing, more predictable refractive outcomes, and better retention of corneal strength and integrity. Although donor adherence was more challenging, DSEK was technically easier and should be less traumatic to anterior chamber structures than earlier posterior grafting techniques.

Letter Regarding: Delayed Late-Onset Severe Progressive Corneal Flattening: A Complication 9 Years After Corneal Collagen Crosslinking

2025-06-25

Rasik B. Vajpayee , Abi Tenen , Colin Chan +1 more | Cornea

Elliptical excision as a surgical approach for large plantar corns

2025-06-25

Yogesh M. Bhingradia , Dipti Dinesh Thorat , Ankita Pundir | Journal of Cutaneous and Aesthetic Surgery

Brittle Cornea Syndrome: Molecular Diagnosis and Management

2025-06-24

Marco Zeppieri , Mattia Gentile , Antonio Acquaviva +6 more | Diagnostics

Background and Clinical Significance: Brittle cornea syndrome (BCS) is a rare, autosomal recessive connective tissue disorder characterized by extreme corneal thinning, high myopia, and increased risk of spontaneous or trauma-induced … Background and Clinical Significance: Brittle cornea syndrome (BCS) is a rare, autosomal recessive connective tissue disorder characterized by extreme corneal thinning, high myopia, and increased risk of spontaneous or trauma-induced ocular rupture. It is primarily caused by mutations in the ZNF469 or PRDM5 genes, which regulate extracellular matrix integrity. Early recognition and diagnosis of BCS are crucial to prevent severe visual impairment. This report presents two genetically confirmed cases of BCS in Albanian siblings, emphasizing the diagnostic value of whole-exome sequencing and individualized surgical management strategies. Case Presentation: Two siblings—a 28-year-old male and a 25-year-old female—presented with progressive visual deterioration and marked corneal thinning (<200 µm). Both had a history of spontaneous ocular rupture following minor trauma in the contralateral eye. Detailed ophthalmologic evaluation revealed keratoglobus, high myopia, and irregular astigmatism. Genetic testing identified the homozygous pathogenic variant c.974delG (p.Cys325LeufsX2) in the PRDM5 gene in both cases. The male underwent penetrating keratoplasty (PKP), achieving a best-corrected visual acuity (BCVA) of 20/30. The female initially underwent deep anterior lamellar keratoplasty (DALK), which was converted to PKP intraoperatively due to central endothelial perforation, resulting in a BCVA of 20/25. Both patients remained complication-free over a 7-year follow-up period. Conclusions: These cases highlight the importance of early genetic diagnosis and a tailored surgical approach in managing BCS. Long-term monitoring and protective strategies are essential to prevent complications. Incorporating genetic testing into clinical practice can enhance diagnostic accuracy and guide personalized treatment plans in patients with hereditary corneal dystrophies.

Isolated human lens interferometric surface radius of curvatures: Implications for the mechanism of accommodation

2025-06-24

Ronald A. Schachar , Ira H. Schachar , John Fabio +4 more | PLoS ONE

Accurate central surface radius of curvature (RoC) measurements of isolated human lenses are essential for understanding the zonular forces required to modify human lens shape to focus at near; i.e., … Accurate central surface radius of curvature (RoC) measurements of isolated human lenses are essential for understanding the zonular forces required to modify human lens shape to focus at near; i.e., accommodate. The human lens can be described as an encapsulated oblate spheroid, with its minor axis aligned with its optical axis. The lens is suspended by zonular fibers that originate from the epithelium of the ciliary body and insert into the equatorial region of the lens capsule. According to Helmholtz’s theory of accommodation when the eye views a distant object (the unaccommodated state), the ciliary muscle is fully relaxed and the zonules are under maximal tension. This tension flattens both the central and peripheral lens surfaces resulting in minimal central optical power (COP). During near focus (accommodation), contraction of the ciliary muscle reduces zonular tension, allowing the elastic capsule to restore the lens to a more rounded shape. This increases the curvature of the lens surfaces, central thickness, and COP. Consequently, isolated lenses without zonular tension from young donors (20–30 years old) would be expected to exhibit maximum COP. However, the companion independent profilometric equation fitting study found that, within central optical zones ≤ 3 mm, 10 fresh isolated lenses from donors in this age range actually had minimal COP. The present study utilizes a white light scanning interferometer (WLSI) with a 10x objective that was validated by measuring RoCs of glass and porcine lenses. Fourteen transparent human lenses were obtained from both eyes of seven donors aged 20–30 years of whom 2 were female and 5 were male. One lens of each donor was placed in preservative media and the contralateral lens in culture media within 11:26 ± 5:15 (range: 4:47–21:54) of the donor’s death. Two of the lenses stored in the culture media had torn capsules and were excluded from the study. Central thickness and WLSI surface vertex RoCs of 12 lenses were measured within 16:27 ± 5:22 (range: 10:11–25:33) of the donor’s death. Mean central thickness, anterior and posterior vertex RoCs and COP were 3.54 ± 0.07 mm, 10.2 ± 0.9 mm, 6.8 ± 1.0 mm, and 20.7 ± 2.1 diopters, respectively. These results confirm the companion study that isolated human lenses have low COP consistent with the unaccommodated state of lenses in vivo . Therefore, relaxation of all the zonules does not increase COP and cannot be the basis for the mechanism of accommodation. These results have implications for the development and treatment of myopia, presbyopia, glaucoma, cortical cataracts and design of accommodative intraocular lenses.

Keratoconus: Diagnosis and Management by Family Physicians

2025-06-24

Alba González Aranda , Sandra S Quitério , Bárbara Junqueira | Cureus

Letter Regarding: Definitive Treatment of Lisch Epithelial Corneal Dystrophy via Staged Keratectomy and Targeted Minor Limbal Excision With Cautery

2025-06-24

Jenna Krivit , Amanda C. Maltry , A. Moss | Cornea

Highly efficient stacking ensemble learning model for automated keratoconus screening

2025-06-24

Zahra J. Muhsin , Rami Qahwaji , Ibrahim Ghafir +4 more | Eye and Vision

Abstract Background Despite extensive research on keratoconus (KC) detection with traditional machine learning models, stacking ensemble learning approaches remain underexplored. This paper presents a stacking ensemble learning method to enhance … Abstract Background Despite extensive research on keratoconus (KC) detection with traditional machine learning models, stacking ensemble learning approaches remain underexplored. This paper presents a stacking ensemble learning method to enhance automated KC screening. Methods This study utilizes a clinical dataset containing detailed corneal data from 2491 cases classified as non-KC (NKC), subclinical KC (SCKC) and clinical KC (CKC). Each cornea is represented by 79 features extracted from Pentacam imaging. Following extensive pre-processing, key corneal features that are strongly correlated with the target diagnosis are identified. These features are the keratometry of the steepest anterior point, surface variance index, vertical asymmetry index, height decentration index, and height asymmetry index. A novel stacking ensemble model is developed using the selected features to improve corneal classification into NKC, SCKC, and CKC by integrating top tree-based classifiers (random forest, gradient boosting, decision trees) with a support vector machine meta-classifier. Results The pre-processing and feature selection techniques reduced the model's parameters to just 6.33% of the original dataset, improving classification performance, and cutting over 85% of the training time. The performance of the developed model was validated and tested on unseen data. Experimental results showed that the model outperforms existing studies, achieving 99.72% accuracy, precision, sensitivity, F1, and F2 scores, with a Matthews correlation coefficient of 0.995. It accurately classified all NKC and CKC cases, with just one misclassification involving an SCKC case. The model also demonstrated consistent performance on 100 additional unseen test cases, underscoring its generalizability and robustness in KC screening. Conclusions By combining the strengths of diverse base models and key Pentacam indices, the stacking ensemble approach ensures reliable, accurate KC screening, providing clinicians with an automated tool for early detection and better patient management.

Investigation of corneal hydration and the impact of cross-linking therapy on water retention using Brillouin spectroscopy, Raman spectroscopy and polarization-sensitive optical coherence tomography

2025-06-24

Jan Rix , Svea Steuer , Jonas Golde +7 more | Frontiers in Bioengineering and Biotechnology

Recently, Brillouin spectroscopy has been proposed as a promising non-invasive tool to evaluate corneal biomechanics, e.g., during corneal cross-linking (CXL) treatment. However, the impact of corneal hydration on the Brillouin … Recently, Brillouin spectroscopy has been proposed as a promising non-invasive tool to evaluate corneal biomechanics, e.g., during corneal cross-linking (CXL) treatment. However, the impact of corneal hydration on the Brillouin shift hampers straightforward interpretation of the measurements, especially when judging on the success of the CXL procedure. Therefore, in this work, we first quantify the effect of corneal (de)hydration on the Brillouin shift revealing that reliable measurements are only possible under constant hydration conditions, which was subsequently achieved by immersing porcine eyes in solution and waiting until an equilibrium state was reached. Investigations showed that Brillouin spectroscopy evaluates the CXL effect mainly indirectly via reduced water uptake, while polarization-sensitive optical coherence tomography evaluates the CXL effect directly via changes in collagen fiber alignment and is therefore insensitive to corneal hydration. Raman spectroscopy is not indicating any alterations in the molecular structure revealing that new cross-links are not created due to the CXL procedure. Compared to large water retention in balanced salt solution, the missing water uptake in dextran-based (16%) solution hampers the evaluation of the CXL effect by Brillouin spectroscopy.

Keratoconus Following Cataract Extraction: A Patient-Centered Perspective

2025-06-23

Firdhaus Zainudin , Yuen Keat Gan , Haireen Kamaruddin +1 more | Cureus

Descemet Membrane Detachment Assessed by Anterior Segment-Optical Coherence Tomography and Managed With Descemetopexy and Corneal Venting Incision: A Case Series

2025-06-23

Shimpa Kundan , Pramod K. Sahu , Akshita Sharma +2 more | Cureus

Advances in Intracorneal Ring Segment (ICRS) Implantation for Keratoconus: A Comprehensive Literature Review, Clinical Insights, and Future Prospects

2025-06-23

Pablo Franquelo Morales , Juan A. Durán | Journal of Clinical Medicine

Keratoconus is a progressive corneal disorder that causes thinning and irregular astigmatism, often leading to significant visual impairment. In the advanced stages, surgical interventions are necessary to restore corneal shape, … Keratoconus is a progressive corneal disorder that causes thinning and irregular astigmatism, often leading to significant visual impairment. In the advanced stages, surgical interventions are necessary to restore corneal shape, improve vision, and enhance contact lens tolerance. Intracorneal ring segments (ICRSs) have emerged as a well-established, minimally invasive option that not only improves vision but also has the potential to delay or prevent the need for corneal transplantation in advanced cases. Recent advancements in the ICRS implantation techniques, patient selection, and femtosecond laser technology have significantly improved the precision and safety of these procedures, reducing complications. The ability to customize the ring parameters—such as thickness, arc length, and positioning—enables a more individualized approach, particularly for patients with irregular astigmatism. Artificial intelligence (AI) is also emerging as a promising tool for optimizing ICRS planning and improving patient outcomes. Although still in the early stages, AI algorithms may refine the treatment strategies by analyzing large datasets, improving the patient selection, and predicting long-term outcomes. Corneal Allogenic Intrastromal Ring Segments (CAIRSs) offer a novel alternative to synthetic ICRSs, with advantages like improved biocompatibility and reduced extrusion risk. However, CAIRSs remain an evolving technique that requires further refinement and long-term evaluation to determine the tissue integration, the durability of the refractive outcomes, and the potential for late-onset complications. In conclusion, ICRSs continue to be a safe and effective option for managing advanced keratoconus. Ongoing refinement of the surgical approaches—combined with advancements such as femtosecond laser technology and the integration of AI—will ensure that both ICRSs and CAIRSs remain key components in the therapeutic arsenal for keratoconus, offering sustained visual improvements and the potential to delay or avoid corneal transplantation.

Mouse Model of Sutured Endothelial Keratoplasty Technique

2025-06-23

Junki Kurita , Takahiko Hayashi , Chihiro Sunouchi +5 more | Journal of Clinical Medicine

Background/Objectives: In this study, a mouse model of sutured endothelial keratoplasty was established and compared with a traditional penetrating keratoplasty (PKP) model in both syngeneic (BALB/c) and allogeneic (C57/BL6) patterns. … Background/Objectives: In this study, a mouse model of sutured endothelial keratoplasty was established and compared with a traditional penetrating keratoplasty (PKP) model in both syngeneic (BALB/c) and allogeneic (C57/BL6) patterns. Methods: For the endothelial keratoplasty (EK) model, chimeric donor tissues consisting of BALB/c epithelium-stroma combined with either syngeneic (BALB/c) or allogeneic (C57/BL6) stroma-endothelium were transplanted into BALB/c mice. Graft transparency, gene expression, and mRNA levels in the transplanted tissues were assessed using polymerase chain reaction (PCR) and quantitative real-time reverse transcription PCR (qRT-PCR) to evaluate inflammatory status. Results: Allogeneic PKP had a higher opacity score than syngeneic PKP. In contrast, syngeneic EK mice had similar opacity scores to those of allogeneic EK mice. Upregulation of CXCR3, the receptor for CXCL10, was demonstrated by qRT-PCR in allogeneic PKP mice but not in allogeneic EK mice. Conclusions: Comparison between the syngeneic and allogeneic PKP groups revealed differences in CXCR3 mRNA expression, suggesting that CXCR3 could be a potential biomarker for rejection in the PKP mouse model. Additionally, the EK model did not show CXCR3 upregulation despite the opaque cornea due to nonspecific inflammation. Therefore, our mouse model was considered to be a successfully established EK model.

Evaluating the Rate and Causes of Non-candidacy After Laser-Assisted in Situ Keratomileusis (LASIK) Screening

2025-06-23

Muhammed Jaafar , Kenneth D Han , Mina M. Sitto +7 more | Cureus

An Open-Source Generalizable Deep Learning Framework for Automated Corneal Segmentation in Anterior Segment Optical Coherence Tomography Imaging

2025-06-20

Lynn Kandakji , Siyin Liu , Shafi Balal +5 more | medRxiv (Cold Spring Harbor Laboratory)

Purpose To develop a deep learning model - Cornea nnU-Net Extractor (CUNEX) - for full-thickness corneal segmentation of anterior segment optical coherence tomography (AS-OCT) images and evaluate its utility in … Purpose To develop a deep learning model - Cornea nnU-Net Extractor (CUNEX) - for full-thickness corneal segmentation of anterior segment optical coherence tomography (AS-OCT) images and evaluate its utility in artificial intelligence (AI) research. Methods We trained and evaluated CUNEX using nnU-Net on 600 AS-OCT images (CSO MS-39) from 300 patients: 100 normal, 100 keratoconus (KC), and 100 Fuchs endothelial corneal dystrophy (FECD) eyes. To assess generalizability, we externally validated CUNEX on 1,168 AS-OCT images from an infectious keratitis dataset of a different device (Casia SS-1000). We benchmarked CUNEX against two recent models, CorneaNet and ScLNet. We then applied CUNEX to our dataset of 194,599 scans from 37,499 patients as preprocessing for a classification model evaluating whether segmentation improves AI prediction, including age, sex, and disease staging (KC and FECD). Results CUNEX achieved Dice similarity coefficient (DSC) and intersection over union (IoU) scores ranging from 94-95% and 90-99%, respectively, across healthy, KC, and FECD eyes. This was similar to ScLNet (within 3%) but better than CorneaNet (8-35% lower). On external validation, CUNEX maintained high performance (DSC 83%; IoU 71%) while ScLNet (DSC 14%; IoU 8%) and CorneaNet (DSC 16%; IoU 9%) failed to generalize. Unexpectedly, segmentation minimally impacted classification accuracy except for sex prediction, where accuracy dropped from 81 to 68%, suggesting sex-related features may lie outside the cornea. Conclusion CUNEX delivers the first open-source generalizable corneal segmentation model using the latest framework, supporting its use in clinical analysis and AI workflows across diseases and imaging platforms. It is available at https://github.com/lkandakji/CUNEX.

Fibrin glue sealing for repeat Descemet’s membrane detachment after deep anterior lamellar keratoplasty: case reports

2025-06-20

Xiong Gong , Jinyu Zhang , Chunxiao Wang +1 more | International Journal of Ophthalmology

Correlation between corneal biomechanical and tomographic parameters in cataract patients

2025-06-20

J H Li , Y. C. Liu , Zi-yuan Liu +1 more | International Journal of Ophthalmology

AIM: To investigate the relationship between preoperative corneal biomechanical properties and corneal tomographic properties in cataract patients. METHODS: The study consisted of 59 eyes of 30 participants who were diagnosed … AIM: To investigate the relationship between preoperative corneal biomechanical properties and corneal tomographic properties in cataract patients. METHODS: The study consisted of 59 eyes of 30 participants who were diagnosed as cataract in Peking University Third Hospital between September 2019 and November 2019. Stepwise multivariable linear regression analysis was calculated to determine the relationship between corneal biomechanical parameters and tomographic parameters. The patients were classified into three groups of with the rule (WTR) astigmatism, against the rule astigmatism and oblique astigmatism. And the differences in corneal parameters among different groups were compared. RESULTS: There were significant differences in the first applanation time (A1T), the first applanation length (A1L), corneal velocity during the first applanation (Vin), the second applanation time (A2T), highest concavity (HC) radius, displacement amount (DA), DA ratio, stiffness parameter A1 (SPA1) and integrated radius (IR) between oblique astigmatism patients and the other two groups. Total corneal steep meridian (K2) was negatively associated with A1L, A1T and corneal velocity during the second applanation (Vout). Patients with higher anterior corneal curvature had lower HC radius and central corneal thickness (CCT; P=0.001 and 0.006, respectively), while the Ambrosio relational thickness to the horizontal profile (ARTh) was higher than those with lower anterior corneal curvature (P=0.009). CONCLUSION: The study reveals that the elasticity of corneal collagen fibers is greater, but the viscoelasticity of cornea is smaller in patients with oblique astigmatism. There is no significant difference in ARTh between patients with different types of astigmatism, that is, the corneal biomechanical specificity of oblique astigmatism group is probably not caused by corneal thickness. Moreover, we find patients with higher anterior corneal curvature has lower HC radius and CCT but higher ARTh than those with lower anterior corneal curvature.

Corneal higher-order aberrations following small incision lenticule extraction for high myopic astigmatism correction

2025-06-20

Yin Liu , Yu Zhou , Nian Xiang +2 more | International Journal of Ophthalmology

AIM: To compare the visual outcomes and corneal higher-order aberrations (HOAs) of patients with high or low myopic astigmatism after small incision lenticule extraction (SMILE). METHODS: A total of 157 … AIM: To compare the visual outcomes and corneal higher-order aberrations (HOAs) of patients with high or low myopic astigmatism after small incision lenticule extraction (SMILE). METHODS: A total of 157 eyes of 157 patients who underwent SMILE were included in this retrospective, nonrandomized, comparative study. All the eyes which were with the rule astigmatism were divided into high astigmatism group (HAG; astigmatism ≤-2.00 D, 73 eyes) and low astigmatism group (LAG; astigmatism ≥-1.00 D, 84 eyes). Visual and refractive examinations were performed, HOAs of the anterior surface, posterior surface, and total cornea of the eyes were evaluated preoperatively and 6mo postoperatively. RESULTS: At the postoperative 6-month follow-up, uncorrected distance visual acuity of 20/20 or better was achieved in 97% and 100% eyes in HAG and LAG respectively and 74% and 100% eyes were within -0.50 D. Vector analysis revealed no significant differences in the correction index (P=0.066), angle of error (P=0.091) or flattening index (P=0.987) between two groups. The magnitude of error was -0.37±0.31 D in HAG and -0.04±0.19 D in LAG (P&#x003C;0.001). Index of success (IOS) was 0.22±0.09 in the HAG and 0.50±0.46 in the LAG (P&#x003C;0.001). HOAs of most anterior, posterior and total cornea significantly increased after SMILE, especially the spherical aberration and coma. For HAG, the SMILE procedure induced significantly higher anterior, posterior and total cornea horizontal coma and total corneal total HOAs compared with LAG (P&#x003C;0.001) and these surgically induced HOAs predominantly originated from the anterior surface of the cornea. CONCLUSION: SMILE surgery induces more HOAs and a mild under-correction of astigmatism in eyes with high astigmatism. The increment in HOAs after SMILE is related to preoperative astigmatism.

Prediction of postoperative vault after implantable collamer lens implantation with deep learning

2025-06-20

Dongqing Yuan , Ying Wang , Hui Zhang +3 more | International Journal of Ophthalmology

AIM: To predict the post-operative vault and the suitable size of the implantable collamer lens (ICL) by comparing the performance of multiple artificial intelligence (AI) algorithms. METHODS: A retrospective analysis … AIM: To predict the post-operative vault and the suitable size of the implantable collamer lens (ICL) by comparing the performance of multiple artificial intelligence (AI) algorithms. METHODS: A retrospective analysis of 83 patients with 132 eyes was conducted from 2020 to 2023. All patients underwent implantation of EVO-V4C ICLs. ICLs were selected based on STAAR's recommended formula. Postoperative vault values were measured using anterior segment optical coherence tomography (ASOCT). First, feature selection was performed on patients' preoperative examination parameters to identify those most closely related to postoperative vault and incorporate them into the machine learning model. Subsequently, four regression models, namely MLP, XGBoost, RFR, and KNN, were employed to predict the vault, and their predictive performances were compared. The ICL size was set as the prediction target, with the vault and other input features serving as new inputs for predicting the ICL size. RESULTS: Among all preoperative parameters, 16 parameters were most closely related to postoperative vault and were included in the prediction model. In vault prediction, XGBoost performed the best in the regression model (R²=0.9999), followed by MLP (R²=0.9987) and RFR (R²=0.8982), while the KNN model had the lowest predictive performance (R²=0.3852). XGBoost achieved a prediction accuracy of 99.8%, MLP had a prediction accuracy of 98.9%, while RFR and KNN had accuracies of 87.1% and 57.4%, respectively. CONCLUSION: AI effectively predicts postoperative vault and determines ICL size. XGBoost outperforms other machine-learning algorithms tested. Its accurate predictions help ophthalmologists choose the right ICL size, ensuring proper vaulting.

Infectious Keratitis After Corneal Cross-Linking: A Retrospective Case Series

2025-06-20

Bjarne Løberg Thorbjørnsen , Marthe Andrea Velle-Skretteberg , Andreas Thorsrud +4 more | Cornea

Purpose: To evaluate the risk of infectious keratitis after corneal cross-linking (CXL) in eyes with corneal ectasia. Methods: In this retrospective case series, we reviewed the medical records of patients … Purpose: To evaluate the risk of infectious keratitis after corneal cross-linking (CXL) in eyes with corneal ectasia. Methods: In this retrospective case series, we reviewed the medical records of patients with a diagnosis code for keratitis over a 6-month period after all CXLs performed in the Department of Ophthalmology at Oslo University Hospital from 2007 to 2020. To compare our results with existing literature, we reviewed studies evaluating the risk of keratitis after CXL. Results: A total of 1809 CXLs were performed in our department during the study period. The annual number of CXLs increased from 3 in 2007 to 219 in 2020. We identified 11 (0.6%) cases registered with a keratitis code within 6 months after CXL, of which the physician considered 5 (0.3%, 95% confidence interval, 0.1%–0.6%) to be procedure-related infectious keratitis. The microbiological agents were Staphylococcus aureus (n = 3), Acanthamoeba (n = 1), or unknown (n = 1). To our knowledge, this is the largest European study to report the risk of infectious keratitis after CXL. The literature review, including papers published up to October 2024, identified 23 relevant studies that reported infectious keratitis in 0% to 2.6% of eyes after CXL treatment. Conclusions: We found a low incidence of infectious keratitis after CXL. Our rate was comparable to that reported in the literature, indicating a low risk of this complication in eyes with corneal ectasia treated with CXL.

A novel metric to monitor early progression in keratoconus: epithelial backscatter

2025-06-20

İbrahim Toprak , Celal Emre Gunes , Cigdem Martin-Seker +1 more | International Ophthalmology

The Impact of Sex Hormones on Keratoconus

2025-06-19

Konstantinos Droutsas , Gunnar Schwarting , Irini Chatziralli +3 more | Journal of Clinical Medicine

Keratoconus (KC) is a progressive non-inflammatory disorder characterized by significant changes in the corneal structure, leading to severe vision loss. Risk factors include eye rubbing, a positive family history, and … Keratoconus (KC) is a progressive non-inflammatory disorder characterized by significant changes in the corneal structure, leading to severe vision loss. Risk factors include eye rubbing, a positive family history, and allergic reactions. There is growing evidence suggesting that sex hormones may influence the development and progression of KC, but the exact mechanisms and extent of their impact remain unclear and controversial. This review aims to examine the current literature on the association between KC and sex hormones and to evaluate the potential of these hormones as clinical markers for diagnosing, prognosticating, and managing KC.

Deciphering the performance of different surface models for corneal topography

2025-06-19

Achim Langenbucher , Nóra Szentmáry , Alan Cayless +2 more | Ophthalmic and Physiological Optics

Abstract Purpose To study the performance of different corneal surface models to be used for ray tracing. Models based on geometric surfaces and polynomial fits were compared and the differences … Abstract Purpose To study the performance of different corneal surface models to be used for ray tracing. Models based on geometric surfaces and polynomial fits were compared and the differences discussed. Methods For this simulation study, five characteristic generic surface configurations were generated: (A) perfect biconic, (B) decentred biconic with white noise, (C) biconic with paracentral hollow simulating the situation after myopic LASIK, (D) biconic with random dot irregularities and (E) rotationally symmetric conic with mid‐peripheral bump simulating the situation of corneal ectasia. A floating best fit sphere (BFS), conic (BFC), biconic (BFBC), fringe Zernike on top of a BFS (BFSZ), fringe Zernike (BFZ) and Gaussian process surface model (BFGP) were fitted and the root‐mean‐squared fit error was analysed. Results Surfaces A and B were well described by BFBC, BFSZ, BFZ and BFGP, but not by BFS and BFC. Surface C was not well represented by BFS, BFC and BFBC, but reasonably with BFSZ and BFZ and quite well with BFGP. Surfaces D and E were poorly represented, especially with BFS, BFC and BFBC, but also with BFSZ and BFZ and quite well with BFGP. There was no systematic difference between the two Zernike representations BFSZ and BFZ, even for surface B. Conclusions Representing corneal point cloud data with a closed surface model plays a key role in ray tracing. Simple surface models such as BFS, BFC or BFBC are easy to handle but do not fully represent clinical situations with local irregularities after corneal refractive surgery or with ectasia.

Reduced quality of life in corneal dystrophy – a prospective case control study

2025-06-19

Carolin Elhardt , Ahmad Zia Aamoon , Lennart Maximilian Hartmann +3 more | BMC Ophthalmology

Abstract Background Corneal dystrophies are a group of rare eye diseases that can cause visual impairment and affect social well-being, independence, and active participation in society. This study presents data … Abstract Background Corneal dystrophies are a group of rare eye diseases that can cause visual impairment and affect social well-being, independence, and active participation in society. This study presents data on the impact of corneal dystrophies on quality of life compared to a healthy control group. Methods This prospective case control study was conducted at the Department of Ophthalmology at the University Hospital Ulm in Germany. The study included 45 patients with corneal dystrophy (excluding Fuchs endothelial dystrophy) between 2021 and 2024, and a control group of 45 healthy patients. All patients completed two questionnaires on quality of life (NEI-VFQ and VF-14). The quality of life was correlated with visual acuity and Scheimpflug imaging parameters, such as higher order aberrations as well as corneal astigmatism, densitometry and pachymetry. Results Thirteen different corneal dystrophies were included; genetic testing confirmed the dystrophies in thirteen patients (13/36 tested; 13/45 total). Mean age was 57 ± 16 years, 60% were female. Compared to the control group, patients with corneal dystrophies reported a significantly worse overall quality of life in the VF-14 ( p < 0.001) and in all categories of the NEI-VFQ ( p < 0.02). There was a high correlation of the quality of life in patients with corneal dystrophy with visual acuity, higher order aberrations and corneal astigmatism, and no correlation with corneal densitometry and pachymetry. Conclusions Our data indicate that corneal dystrophies have a significant impact on an individual's quality of life in many ways. These findings highlight the importance of identifying and treating these diseases to enhance overall well-being and active participation in daily life.

Femtosecond Laser-Assisted Donor and Recipient Preparation for Bowman Layer Transplantation

2025-06-19

Rosemarie Schlosser , Annekatrin Rickmann , Peter Szurman +6 more | Journal of Clinical Medicine

Objectives: A Ziemer LDV Z8 femtosecond laser (FSL) was used to obtain optimal cutting parameters with precise settings for donor and recipient preparations for Bowman layer transplantation. Methods: Of 48 … Objectives: A Ziemer LDV Z8 femtosecond laser (FSL) was used to obtain optimal cutting parameters with precise settings for donor and recipient preparations for Bowman layer transplantation. Methods: Of 48 human research corneas examined, 32 were used for Bowman layer preparation (donor) and 16 for pocket preparation (recipient) using the LDV Z8 FSL. The cutting thickness of the Bowman layer, pocket depth, and corresponding laser settings were varied. The quality of sections was evaluated based on the occurrence of adhesions, bridges, or perforations. Histological specimens were prepared and analyzed. Results: Preparation of the Bowman layer and recipient pocket was possible using all selected settings. The thinner the Bowman layer and the more superficial the pocket preparation, the higher the risk of perforation was. Considering the fact that the Bowman layer was cut as thinly as possible, a Bowman layer thickness of 30 µm showed a 100% success rate. Bowman layers cut at 25 µm had a lower success rate (50%). The pocket depth of 150 µm showed a 100% success rate in the preparation. Histological processing revealed smooth, precisely cut edges of Bowman layers and pockets. Implantation into the pocket was successful in all cases. Conclusions: Both Bowman layer and pocket preparation were technically and surgically feasible using the LDV Z8 FSL, and the prepared Bowman layers were thinner than those reported in previous studies. The optimal Bowman layer thickness was 30 µm, and a resection depth of 150 µm was used to prepare the pockets safely.

Impact of Counseling on the Hospital Cornea Retrieval Programme: A Prospective Study

2025-06-19

Anil Thakur , Aditi Dubey , Kavita Kumar | Cureus

Combination therapy in the patient with glaucoma and endothelial corneal dystrophy treatment: clinical case

2025-06-19

Г. Ш. Аржиматова , I. B. Alekseev , A. I. Ibraimov +1 more | Journal of clinical practice

Background. Penetrating keratoplasty improves visual acuity in patients with various corneal conditions. However, like any form of surgery it can lead to complications and there are number of contraindications. Uncompensated … Background. Penetrating keratoplasty improves visual acuity in patients with various corneal conditions. However, like any form of surgery it can lead to complications and there are number of contraindications. Uncompensated glaucoma is one of the poor prognostic factors for penetrating keratoplasty. Penetrating keratoplasty can result in postoperative reactive hypertension, although it is not a common condition. This complication is associated with glaucoma patients whereas patients who has not been previously diagnosed with glaucoma suffer from postoperative reactive hypertension much less. Increased intraocular pressure in glaucoma patients can lead to disease progression and graft failure. Clinical case description. This clinical case presents a juvenile glaucoma patient, who underwent surgery for glaucoma several times and after that underwent the EX-PRESS glaucoma filtration device implantation. The EX-PRESS device contacted with the posterior surface of the cornea that resulted in endothelial corneal dystrophy development with corneal opacities and pain. The EX-PRESS device was removed and penetrating keratoplasty was performed, since critical flicker frequency was high (30 Hz), so that a sufficiently good visual outcome was expected. However, despite the maximum medical therapy in glaucoma, intraocular pressure remained high, so transscleral diode laser cyclophotocoagulation had been applied. Conclusion. The clinical case demonstrates the effectiveness of transscleral diode laser cyclophotocoagulation in the patient with repeatedly operated refractory glaucoma before penetrating keratoplasty. Key words: clinical case, transscleral diode laser cyclophotocoagulation, refractory glaucoma, juvenile glaucoma, intraocular pressure, penetrating keratoplasty. For citation: Arzhimatova GSh, Alekseev IB, Ibraimov AI, Popova LA. Combination therapy in the patient with glaucoma and endothelial corneal dystrophy treatment: clinical case. Journal of Clinical Practice . 2024;00(0):0–00. doi:

Short-term digital ocular massage may weaken corneal biomechanics

2025-06-18

Andrew Lam , Sang-Ho Lee , Mason W. S. Mui +1 more | Frontiers in Bioengineering and Biotechnology

Purpose Digital ocular massage has been demonstrated to reduce intraocular pressure (IOP). However, its influence on corneal biomechanics remains unclear. In this study, a device employing Corneal Visualization Scheimpflug Technology … Purpose Digital ocular massage has been demonstrated to reduce intraocular pressure (IOP). However, its influence on corneal biomechanics remains unclear. In this study, a device employing Corneal Visualization Scheimpflug Technology (Corvis ST) was used to monitor changes in IOP and corneal biomechanics following short-term digital ocular massage in low and high myopes. Methods In total, 29 low myopes and 29 high myopes participated in this study. The right eyes (treatment eyes) underwent digital ocular massage for 5 min, whereas the left eyes (control eyes) remained closed during the procedure. Biomechanically-corrected IOP (bIOP) was measured in both eyes by using Corvis ST at three time points: before the ocular massage, immediately after the ocular massage, and 15 min post-massage. Dynamic corneal response (DCR) parameters were also monitored, namely, peak distance (PeakDist), highest concavity time (HCT), deformation amplitude (DA), deflection amplitude (DefleA), stress-strain index (SSI), time taken to reach the second applanation (A2T), and velocity required to reach the second applanation (A2V). Results At baseline, the participants exhibited comparable bIOP in both eyes. A significant reduction in bIOP was observed in the treatment eyes immediately after ocular massage (low myopes: 16.15 ± 2.79 vs. 14.82 ± 3.20 mmHg, p &lt; 0.05; high myopes: 16.81 ± 1.51 vs. 15.39 ± 1.70 mmHg, p &lt; 0.05). Corneal biomechanics at baseline were comparable between the treatment and control eyes. High myopes exhibited more deformable corneas, characterized by a shorter HCT (treatment eyes: 17.30 ± 0.41 vs. 17.72 ± 0.30 msec, p &lt; 0.001; control eyes: 17.33 ± 0.32 vs. 17.55 ± 0.44 msec, p = 0.023), and lower SSI (treatment eyes: 0.739 ± 0.100 vs. 0.848 ± 0.114, p &lt; 0.001; control eyes: 0.741 ± 0.103 vs. 0.858 ± 0.112, p &lt; 0.001) than low myopes at baseline. Immediately after ocular massage, the treatment eyes in both groups exhibited shorter A2T, higher A2V, larger PeakDist, and higher DA and DefleA. Corneal biomechanics in the control eyes remained stable throughout. All DCR parameters returned to baseline levels 15 min after the ocular massage. Conclusion Short-term digital ocular massage results in a temporary reduction in bIOP. The observed changes, including shorter A2T, higher A2V, larger PeakDist, and greater DA and DefleA indicated a greater corneal deformability after ocular massage. These findings support the potential association between eye rubbing and the etiology or progression of keratoconus.

New augmented reality application for improving clinical education and patient-doctor interaction in remotely-assisted ophthalmology consultations

2025-06-18

José S. Velázquez , Eduardo Paños , José González-Cabrero +2 more | Virtual Reality

Abstract Effectively explaining keratoconus patients their condition and how it can be treated, or teaching new doctors the particularities of this disease, is always a difficult task, but it becomes … Abstract Effectively explaining keratoconus patients their condition and how it can be treated, or teaching new doctors the particularities of this disease, is always a difficult task, but it becomes even more difficult in a framework of remotely assisted consultation. This paper introduces KERATOCONUS AR, an application for mobile devices that utilizes marker-based augmented reality (AR) to provide clear and precise visualization of three-dimensional (3D) models of corneas affected by different degrees of keratoconus, as well as corneas treated with different healing approaches. The KERATOCONUS AR application has been specifically designed to offer an overview of keratoconus, along with access to two significant classification systems: the Amsler-Krumeich scale and the RETICS scale. Furthermore, the application incorporates AR models of typical corneas, both complete and cross-sectioned, representing each grade from the aforementioned scales. It also provides information on potential treatments for keratoconus, including intra-stromal rings, collagen cross-linking, and penetrating keratoplasty, accompanied by concise descriptions. The application enables patients to better understand their pathology and treatment options, particularly when used in face-to-face clinical consultations. However, its true potential is realized when employed with patients in remote locations or under circumstances of movement restrictions, such as those experienced during the COVID-19 pandemic. ERATOCONUS AR offers an innovative approach to enhance patient and future doctors understanding of keratoconus by providing interactive and immersive experience through marker-based AR technology. By visualizing 3D models and offering comprehensive information on classification systems and treatment options, the application bridges the gap in patient education and improves communication between healthcare providers and patients. The utilization of KERATOCONUS AR has the potential to transform the patient experience, facilitating better-informed decision-making and optimizing the management of keratoconus.

Posterior dislocation and early retrieval of a Descemet stripping automated endothelial keratoplasty graft

2025-06-18

Philip Francis Stanley , Tun Hang Yeo , Jenny Chen Jue | Research Square (Research Square)

<title>Abstract</title> Purpose: This case report seeks to document an rare case of posterior dislocation of Descemet stripping automated endothelial keratoplasty (DSAEK) graft in a patient with subluxed intraocular lens one … <title>Abstract</title> Purpose: This case report seeks to document an rare case of posterior dislocation of Descemet stripping automated endothelial keratoplasty (DSAEK) graft in a patient with subluxed intraocular lens one day post operation. Observations: A 70-year-old man with a background of subluxed intraocular lens in a non-vitrectomized eye with pseudophakic bullous keratopathy underwent DSAEK. Review on post operative day one noted a posteriorly dislocated graft. Graft repositioning was done on the same day without complications. Conclusions and Importance: This case report shows the possibility of DSAEK graft dislocation post operation in a non-vitrectomized eye but with compromised barrier between anterior and posterior chambers of the eye.

A Hybrid Transformers-based Convolutional Neural Network Model for Keratoconus Detection in Scheimpflug-based Dynamic Corneal Deformation Videos

2025-06-18

Hazem Abdelmotaal , Rossen Hazarbasanov , Ramin Salouti +6 more | Journal of Ophthalmic and Vision Research

Purpose: To assess the performance of a hybrid Transformer-based convolutional neural network (CNN) model for automated detection of keratoconus in stand-alone Scheimpflug-based dynamic corneal deformation videos (DCDVs). Methods: We used … Purpose: To assess the performance of a hybrid Transformer-based convolutional neural network (CNN) model for automated detection of keratoconus in stand-alone Scheimpflug-based dynamic corneal deformation videos (DCDVs). Methods: We used transfer learning for feature extraction from DCDVs. These feature maps were augmented by self-attention to model long-range dependencies before classification to identify keratoconus directly. Model performance was evaluated by objective accuracy metrics based on DCDVs from two independent cohorts with 275 and 546 subjects. Results: The model’s sensitivity and specificity in detecting keratoconus were 93% and 84%, respectively. The AUC of the keratoconus probability score based on the external validation database was 0.97. Conclusion: The hybrid Transformer-based model was highly sensitive and specific in discriminating normal from keratoconic eyes using DCDV(s) at levels that may prove useful in clinical practice.

Protocol for immunofluorescent staining, high-resolution imaging, and spatial projection of Schlemm’s canal in mouse whole-mount corneal limbus tissue

2025-06-18

Weifa Wang , Peiyao Peng , Wenbin Hu +4 more | STAR Protocols

The Evolution of Endothelial Therapeutics

2025-06-17

Greg Moloney , Antoine Sylvestre-Bouchard , Michael J. Holdsworth | Canadian Eye Care Today

Corneal endothelial diseases comprise a spectrum of conditions that critically affect the health and transparency of the cornea, posing unique challenges for ophthalmologists. The most prevalent among these is Fuchs’ … Corneal endothelial diseases comprise a spectrum of conditions that critically affect the health and transparency of the cornea, posing unique challenges for ophthalmologists. The most prevalent among these is Fuchs’ endothelial corneal dystrophy (FECD), which accounts for approximately 39% of all corneal transplants globally. Bullous keratopathy (BK) can affect the entire cornea, leading to painful blisters that may become infected. Other rarer pathologies, such as iridocorneal endothelial syndrome, posterior polymorphous corneal dystrophy, and congenital hereditary endothelial dystrophy, present unique diagnostic and therapeutic challenges. Additionally, graft failure remains a notable indication for treatment. High-risk cases experience failure rates exceeding 35% within 3 years, with endothelial rejection accounting for half of the cases. Corneal transplants have been considered the gold standard for decades, with advancements in surgical techniques leading to shorter operating times, faster visual recovery, and improved outcomes. However, the growing global shortage of transplant-grade donor tissue further complicates treatment, underscoring the urgent need for innovative approaches such as genetic and cell-based therapies.

Etiology of Iridocorneal Endothelial Syndrome: Viral Infection and Immune Suppression

2025-06-17

Jiaxin Zhang , Bowei Yuan , Rongmei Peng +7 more | Cornea

Purpose: Iridocorneal endothelial (ICE) syndrome is a rare ocular disease affecting the anterior segment, leading to cornea edema and glaucoma. Its unclear etiology limits clinical management to symptomatic interventions. This … Purpose: Iridocorneal endothelial (ICE) syndrome is a rare ocular disease affecting the anterior segment, leading to cornea edema and glaucoma. Its unclear etiology limits clinical management to symptomatic interventions. This study uses diverse methodologies to explore potential viral sequences in patients’ samples and to elucidate the transcriptomic profiles of ICE cells. Methods: We used a convenience sampling method, including all eligible patients for analysis. We reviewed polymerase chain reaction (PCR) results for herpes viruses across all samples obtained from ICE syndrome patients at our institution. To further delve into potential pathogenic involvement, we used metagenomic sequencing and whole-genome sequencing techniques on samples. We used smart-seq2 RNA sequencing to explore the transcriptomic features of ICE cells compared with normal cells. Results: In our PCR tests involving 141 samples, only two positive results were detected in the aqueous humor. Furthermore, the application of metagenomic sequencing on three aqueous humor samples and three corneal endothelium samples, along with whole-genome sequencing on one corneal endothelium sample, yielded no evidence of viral sequences. RNA sequencing revealed upregulated cell growth and neuronal death in ICE cells, alongside downregulated expression in extracellular matrix composition, cell adhesion, and immune response functions. Conclusions: Our findings from multiple sequencing assays consistently indicate the absence of compelling evidence supporting viral infection in patients with ICE syndrome. Furthermore, the transcriptional analysis of ICE cells reveals a distinct profile characterized by upregulated cell growth and suppressed immune response. Future studies are necessary to validate these findings and improve the generalizability of the results.

Six-month Performance and Safety of an Iris-Fixated Multifocal Intraocular Lens for Presbyopia Correction in Phakic Eyes

2025-06-17

Joukje C. Wanten , Julián Cezón , Rudy M.M.A. Nuijts +7 more | Journal of Cataract & Refractive Surgery

Purpose: To evaluate the six-month effectiveness and safety of a novel foldable multifocal iris-fixated phakic IOL (pIOL) for presbyopia correction. Setting: Multicenter study at 7 sites. Design: Nonrandomized prospective clinical … Purpose: To evaluate the six-month effectiveness and safety of a novel foldable multifocal iris-fixated phakic IOL (pIOL) for presbyopia correction. Setting: Multicenter study at 7 sites. Design: Nonrandomized prospective clinical trial. Methods: Presbyopic patients without cataracts undergoing bilateral multifocal pIOL implantation (Ophtec ArtiPlus) were studied. The primary outcome for efficacy was the visual acuity at distance, intermediate, and near. Secondary outcomes included endothelial cell density (ECD), postoperative refraction, binocular defocus curve, vision quality, spectacle independence, and patient satisfaction. Results: A total of 49 subjects (98 eyes) were included. At six months, the mean binocular uncorrected distance intermediate, and near visual acuity were -0.05±0.09, -0.02±0.07, and 0.02±0.08 logMAR, respectively. The ECD remained stable with a mean value of 2771±289 cells/mm 2 at six months postoperatively. The mean spherical equivalent was -0.42±0.33 diopters (D), with 95% eyes having a prediction error within ±1.0D and 77% within ±0.5D. The binocular distance-corrected defocus curve showed a visual acuity of 0.20 logMAR or better over a range of +1.0D to -3.5D. Patient satisfaction was high, with a mean score of 3.5 on a 4-point scale, and 83% of the patients reported spectacle independence. 47%, 35%, and 96% of patients reported experiencing glare, halos, and starbursts at well-tolerated levels, respectively. Notably, only 2% of patients found halos and starbursts to be very bothersome. Conclusion: Bilateral ArtiPlus multifocal pIOL implantation demonstrated good visual acuity from distant to near and maintained stable ECD over six months. Patients reported high levels of satisfaction and spectacle independence, despite some optical disturbances.

EARLY DETECTION OF SUBCLINICAL KERATOCONUS USING OPTICAL COHERENCE TOMOGRAPHY (LITERATURE REVIEW)

2025-06-17

R.Kh. Rajabli | Azerbaijan Journal of Ophthalmology

The evaluation of final corneal epithelial thickness measurements, especially during preoperative screening for refractive surgery, has begun to receive special attention in both clinical and scientific research. Local or diffuse … The evaluation of final corneal epithelial thickness measurements, especially during preoperative screening for refractive surgery, has begun to receive special attention in both clinical and scientific research. Local or diffuse epithelial pachymetry topographic abnormalities can significantly affect the overall corneal refractive power and may mask some underlying stromal abnormalities. Therefore, separate analysis of the corneal epithelium and stroma may provide additional information for the diagnosis of keratoconus. Assessment of focal epithelial thickness variation using Anterior Segment High-Resolution Optical Coherence Tomography (AS-OCT) is considered a more sensitive method for the early detection of keratoconus in eyes with normal topography and clinical parameters. This is particularly important for the early diagnosis of the disease, especially in selecting appropriate strategies for the prevention and treatment of iatrogenic keratectasia. Corneal epithelial imaging is an important and must-have tool in the armamentarium of a refractive surgeon. Key words: subclinical keratoconus, optical coherence tomography, iatrogenic keratectasia, corneal epithelial thickness, medical diagnostic devices

Relationship between acceleration of axial elongation and ocular biometry in schoolchildren

2025-06-17

Takehiro Yamashita , Hiroto Terasaki , Takuto Hamada +4 more | Japanese Journal of Ophthalmology

Rock-Inhibitors eyedrops preventing cataract surgery induced corneal failure in Fuchs corneal dystrophy

2025-06-17

Daniele Gaudenzi , Chiara De Gregorio , Francesco Cutrupi +3 more | European Journal of Ophthalmology

Purpose To evaluate the safety and efficacy of prophylactic Ripasudil in maintaining corneal endothelial function and preventing corneal failure in patients with late-stage Fuchs corneal dystrophy (FCD) undergoing femtolaser-assisted cataract … Purpose To evaluate the safety and efficacy of prophylactic Ripasudil in maintaining corneal endothelial function and preventing corneal failure in patients with late-stage Fuchs corneal dystrophy (FCD) undergoing femtolaser-assisted cataract surgery. Major findings This prospective, randomized, open-label, controlled interventional study included 41 eyes from 27 patients, 27 eyes treated with Ripasudil and 14 with hyaluronic acid as a control. Treatment was administered from 1 month before cataract surgery through 2 months postoperatively. Primary outcomes included best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density and morphology, assessed at baseline, 3 months, and 9 months after surgery. Statistical analysis was performed using the unpaired t-test with Welch's correction and the Wilcoxon matched-pairs test, with a significance threshold of p < 0.05. The Ripasudil group showed a significant improvement in BCVA, from0.3 ± 0.3 to 0.2 ± 0.2 LogMAR ( p = 0.01), along with stable CCT (556.3 ± 76.4 μm at baseline vs. 563.3 ± 72.2 μm at post-operative month 3, p = 0.39). In contrast, the control group demonstrated no significant improvement in BCVA ( p = 0.13) and a significant increase in CCT (from 591.9 ± 59.3 μm to 658.4 ± 74.6 μm, p < 0.01). Endothelial cell density, polymegathism, and pleomorphism remained stable in both groups. At 9 months, Ripasudil-treated eyes continued to show stability in both BCVA and CCT, with no adverse events reported. Conclusion Ripasudil demonstrated a protective effect on the corneal endothelium during cataract surgery in late-stage FCD patients, with better visual outcomes and reduced postoperative corneal edema.

Outcomes of Photorefractive Keratectomy in First-Degree Relatives of Patients With Keratoconus

2025-06-17

Sepehr Feizi , Mohammad Ali Javadi , Kia Bayat +3 more | Cornea

Purpose: The aim of this study was to evaluate the safety and efficacy of photorefractive keratectomy (PRK) for treating myopic astigmatism in first-degree relatives of patients with keratoconus. Methods: This … Purpose: The aim of this study was to evaluate the safety and efficacy of photorefractive keratectomy (PRK) for treating myopic astigmatism in first-degree relatives of patients with keratoconus. Methods: This retrospective comparative interventional case series included 146 eyes of 73 consecutive first-degree relatives of patients with keratoconus (group 1). A control group consisted of 150 right eyes from 150 consecutive individuals with no family history of keratoconus (group 2). All eyes had normal clinical and topographic and tomographic examinations preoperatively and underwent PRK for myopic astigmatism. Postoperative visual acuity and refractive error were compared between the groups. Primary outcomes included efficacy, safety, and the occurrence of complications such as corneal ectasia. Results: The mean participant age was 27.0 ± 5.3 years in group 1 and 25.8 ± 4.9 years in group 2 ( P = 0.09), with follow-up periods of 65.2 ± 38.2 and 63.8 ± 46.8 months, respectively ( P = 0.81). The postoperative corrected distance visual acuity was 0.00 ± 0.02 and 0.01 ± 0.03 logarithm of the minimum angle of resolution in groups 1 and 2, respectively ( P = 0.26). The mean postoperative spherical equivalent refraction was −0.17 ± 0.37 diopters (D) in group 1 and -0.12 ± 0.33 D in group 2 ( P = 0.22), with a mean refractive astigmatism of −0.15 ± 0.28 D and −0.09 ± 0.31 D, respectively ( P = 0.11). The safety index was 1.01 ± 0.12 in group 1 and 1.00 ± 0.10 in group 2 ( P = 0.29) while the efficacy index was 0.94 ± 0.16 and 0.95 ± 0.16, respectively ( P = 0.98). No cases of corneal ectasia were observed in either group. Conclusions: PRK is a safe and effective treatment for myopic refractive error in first-degree relatives of patients with keratoconus who have normal preoperative clinical and topographic/tomographic findings.

Age, gender and regional/ethnic variations in emmetropic axial growth rate

2025-06-16

Thomas Naduvilath , Xiangui He , Kathryn J. Saunders +7 more | Ophthalmic and Physiological Optics

Abstract Aim To determine age‐specific axial growth rate in emmetropic eyes and investigate the effect of sex and region/ethnicity using population‐based data. Methods A retrospective analysis of five population‐based studies … Abstract Aim To determine age‐specific axial growth rate in emmetropic eyes and investigate the effect of sex and region/ethnicity using population‐based data. Methods A retrospective analysis of five population‐based studies conducted in the United Kingdom, Sweden and China. A total of 16,526 datapoints from 6753 participants, aged 6–16.9 years, with spherical equivalents (SE) from −0.49 to +1 D were analysed. Axial length was modelled using a Generalised Estimating Equation with region/ethnicity and sex included as fixed factors and age, SE and corneal radius of curvature as covariates. Model‐based estimates of axial length were used to derive age‐specific axial growth rates, maintaining SE at 0.00 D and constant corneal radius of curvature. Results Within this emmetropic population, axial length was weakly correlated with SE ( r = −0.24) but strongly associated with corneal curvature ( r = 0.76). Gender, region/ethnicity, SE, corneal curvature and inverse function of age were associated with axial length of emmetropic eyes. Axial length was longer in males than females by 0.55 mm (95% CI: 0.53–0.56 mm) in East‐Asian emmetropic eyes and by 0.50 mm (95% CI: 0.49–0.52 mm) in European eyes; however, axial growth rate was marginally greater in males by 7%. Axial length of East‐Asian eyes was significantly greater than Europeans by 0.14 mm (95% CI: 0.12–0.16 mm) in males and 0.12 mm (95% CI: 0.11–0.14 mm) in females, but axial growth rate was not significantly different between regions/ethnicities ( p = 0.06). Axial growth rate decreased non‐linearly from 0.17 to 0.03 mm/year in males and 0.16 to 0.02 mm/year in females between 6 and 16 years. Conclusions Emmetropic axial growth rate between 6 and 16 years is non‐uniform with greater growth rate at younger ages and in males. Growth rates estimated by maintaining constant SE and corneal curvature are lower or similar to previous estimates and may be used to set goals for myopia treatment.

Efficacy and safety of a new combined treatment method of ultraviolet corneal collagen crosslinking in combination with personalized transepithelial photorefractive keratectomy of keratoconus. Pirogovsky protocol

2025-06-14

A.A. Golyakov , R.R. Fayzrakhmanov , М. М. Шишкин +1 more | Russian Ophthalmological Journal

Purpose . To evaluate the efficacy and safety of our proposed method for treating keratoconus (Pirogov protocol), including patients with a corneal thickness of less than 450 mm, providing for … Purpose . To evaluate the efficacy and safety of our proposed method for treating keratoconus (Pirogov protocol), including patients with a corneal thickness of less than 450 mm, providing for corneal collagen UV crosslinking in combination with personalized transepithelial photorefractive keratectomy (PRK). Material and methods . Sixty patients (60 eyes) aged 30,6 ± 9,5 with progressive keratoconus stages I–II were divided into two groups: group 1 (30 patients, 30 eyes) received the standard Dresden UV crosslinking protocol, while group 2 (30 patients, 30 eyes) received the Pirogov protocol (one-time corneal UV crosslinking and personalized PRK on the Microscan Visum excimer laser). All patients underwent visometry, refractometry, keratometry, keratopachymetry, keratotopography and optical coherence tomography of the cornea before, immediately after treatment and after 1, 3, 6, 12 and 24 months. Results . In the group of patients operated on according to the Pirogov protocol, after 1 month there was a significant (p < 0.05) increase in uncorrected and best-corrected visual acuity relative to baseline values (before surgery 0.11±0.1 and 0.53 ± 0.22; after 1 month 0.48 ± 0.27 and 0.75 ± 0.2, respectively), improvement in refractive indices (spherical equivalent of refraction decreased from –5.08 ± 0.20 D to –1.04 ± 1.56 D) and keratotopographic corneal indices (KCI, KSI, ESI of the anterior corneal surface, SAI, SRI), the values of which remained stable during 2 years of observation. Similar parameters of the control group did not change significantly during the entire observation period. Conclusion . The developed Pirogov protocol for the treatment of progressive keratoconus stages I–II showed safety and high efficiency.

Ten-year outcomes of effective optical zone and decentration analysis after keratorefractive lenticule extraction for moderate and high myopia

2025-06-13

Tie Jun Cui , Yangyi Huang , Fei Xia +4 more | Lasers in Medical Science

Diagnóstico de Queratocono Pediátrico por Tomografía Corneal

2025-06-13

Alexia Carla Romanelli Zuazo | Highlights of ophthalmology.

Pediatric Keratoconus Diagnosis by Corneal Tomography

2025-06-13

Alexia Carla Romanelli Zuazo | Highlights of ophthalmology.

Median canaliform dystrophy of Heller

2025-06-13

Siqi Li , Yanhong Shou | QJM

Letter Regarding: Comment on “Descemet Membrane Endothelial Keratoplasty with and Without Graft Deswelling: A Prospective Clinical Study”

2025-06-12

Qinling Jiang , Lin Mou | Cornea

Transplantation eines kornealen allogenen intrastromalen Ringsegmentes (CAIRS) zur Behandlung von Keratektasien

2025-06-12

Hyeck-Soo Son , Victor A Augustin , Ramin Khoramnia +3 more | Deleted Journal

Corneal allogeneic intrastromal ring segments (CAIRS) were recently introduced as a novel treatment modality for corneal diseases, such as keratoconus or postoperative ectasia after laser-refractive surgery. Contrary to other conventional … Corneal allogeneic intrastromal ring segments (CAIRS) were recently introduced as a novel treatment modality for corneal diseases, such as keratoconus or postoperative ectasia after laser-refractive surgery. Contrary to other conventional surgical treatments for ectatic conditions, CAIRS is minimally invasive, freely adjustable in its size and length and has a short learning curve as well as a good safety profile. This article provides step-by-step instructions for the performance and integration of the CAIRS procedure into clinical practice.

STARGUS: a comparative study of a new swept-source biometer and B-mode ultrasound in dense cataracts

2025-06-12

Héloïse Torres-Villaros , M. Strého , Didier Hoa +1 more | Graefe s Archive for Clinical and Experimental Ophthalmology