Medicine › Ophthalmology

Ocular and Laser Science Research

Works Count: 38248

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Description

This cluster of papers focuses on the effects of laser radiation on ocular health, including retinal damage, macular injury, thermal damage thresholds, and the hazards associated with laser pointers. It also discusses guidelines for exposure limits, choroidal neovascularization, and the impact of infrared and visible radiation on the eyes.

Keywords

Laser Eye Injuries; Retinal Damage; Ocular Radiation Exposure; ICNIRP Guidelines; Macular Injury; Thermal Damage Thresholds; Laser Pointer Hazards; Choroidal Neovascularization; Infrared and Visible Radiation; Photothermal Damage

Ocular effects of ultraviolet radiation from 295 to 365 nm.

1977-10-01

Donald G. Pitts , Anthony P. Cullen , PIERRETTE D. HACKER

A 5,000 watt Xe-Hg source and a double monochromator were used to produce 6.6 nm. full band-pass ultraviolet (UV) radiation. Pigmented rabbit eyes were exposed to the 6.6 nm. band-pass … A 5,000 watt Xe-Hg source and a double monochromator were used to produce 6.6 nm. full band-pass ultraviolet (UV) radiation. Pigmented rabbit eyes were exposed to the 6.6 nm. band-pass UV radiant energy in 5 nm. steps from 295 to 320 nm. and at random intervals above 320 nm. Corneal and lenticular damage was assessed and classified with a biomicroscope. Corneal threshold radiant exposure (Hc) rose very rapidly from 0.022 Jcm.-2 at 300 nm. to 10.99 Jcm.-2 at 335 nm. Radiant exposures exceeding 2 x Hc resulted in irreversible corneal damage. Lenticular damage was limited to wavebands above 295 nm. The action spectrum for the lens began at 295 nm. and extended to about 315 nm. Permanent lenticular damage occurred at radiant exposure levels approximately twice the threshold for lenticular radiant exposure. The importance in establishing both corneal and lenticular damage criteria is emphasized.

Berechnung der nat�rlichen Linienbreite auf Grund der Diracschen Lichttheorie

1930-01-01

V. F. Weisskopf , E. P. Wigner

Diabetic Maculopathy

1983-11-01

George H. Bresnick

THE RESPONSE OF SINGLE OPTIC NERVE FIBERS OF THE VERTEBRATE EYE TO ILLUMINATION OF THE RETINA

1938-01-31

H. K. Hartline

ANALYSIS OF RECEPTIVE FIELDS OF CAT RETINAL GANGLION CELLS

1965-09-01

R.W. Rodieck , Jonathan Stone

Improved electrode for electroretinography.

1979-09-01

William W. Dawson , G L Trick , C A Litzkow

Corneal electrodes useful for clinical electroretinography require topical anesthesia, interfere with vision, can abrade, and are not well accepted by most children and many adults. A low mass conductive thread, … Corneal electrodes useful for clinical electroretinography require topical anesthesia, interfere with vision, can abrade, and are not well accepted by most children and many adults. A low mass conductive thread, corneal (DTL) electrode is described and comparatively tested against the Burian-Allen electrode. The DTL electrode was found to have few of the limitations of the hard contact lens electrode. Furthermore, the DTL electrode signal quality was comparable to that of the Burian-Allen electrode and provided less between-patient variability.

Understanding the performance of free-space optics [Invited]

2003-06-06

Scott Bloom , Eric J. Korevaar , John J. Schuster +1 more

Given the relative newness of free-space optics (FSO) technology in commercial applications, few standardized metrics exist for comparing the performance of different systems. Our goal here is to explain some … Given the relative newness of free-space optics (FSO) technology in commercial applications, few standardized metrics exist for comparing the performance of different systems. Our goal here is to explain some of the design issues surrounding FSO systems and to provide sufficient information to allow potential users to evaluate the suitability of a specific FSO system for a particular application. In addition, we attempt to define the realistic performance limitations of FSO on the basis of existing technology and also to set reasonable expectations with regard to atmospheric conditions.

ENERGY, QUANTA, AND VISION

1942-07-20

Selig Hecht , Simon Shlaer , M. H. Pirenne

1. Direct measurements of the minimum energy required for threshold vision under optimal physiological conditions yield values between 2.1 and 5.7 x 10(-10) ergs at the cornea, which correspond to … 1. Direct measurements of the minimum energy required for threshold vision under optimal physiological conditions yield values between 2.1 and 5.7 x 10(-10) ergs at the cornea, which correspond to between 54 and 148 quanta of blue-green light. 2. These values are at the cornea. To yield physiologically significant data they must be corrected for corneal reflection, which is 4 per cent; for ocular media absorption, which is almost precisely 50 per cent; and for retinal transmission, which is at least 80 per cent. Retinal transmission is derived from previous direct measurements and from new comparisons between the percentage absorption spectrum of visual purple with the dim-vision luminosity function. With these three corrections, the range of 54 to 148 quanta at the cornea becomes as an upper limit 5 to 14 quanta actually absorbed by the retinal rods. 3. This small number of quanta, in comparison with the large number of rods (500) involved, precludes any significant two quantum absorptions per rod, and means that in order to produce a visual effect, one quantum must be absorbed by each of 5 to 14 rods in the retina. 4. Because this number of individual events is so small, it may be derived from an independent statistical study of the relation between the intensity of a light flash and the frequency with which it is seen. Such experiments give values of 5 to 8 for the number of critical events involved at the threshold of vision. Biological variation does not alter these numbers essentially, and the agreement between the values measured directly and those derived from statistical considerations is therefore significant. 5. The results clarify the nature of the fluctuations shown by an organism in response to a stimulus. The general assumption has been that the stimulus is constant and the organism variable. The present considerations show, however, that at the threshold it is the stimulus which is variable, and that the properties of its variation determine the fluctuations found between response and stimulus.

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Confocal scanning laser ophthalmoscope

1987-04-15

Robert H. Webb , George W. Hughes , François C. Delori

A confocal scanning imager moves an illumination spot over the object and a (virtual) detector synchronously over the image. In the confocal scanning laser ophthalmoscope this is accomplished by reusing … A confocal scanning imager moves an illumination spot over the object and a (virtual) detector synchronously over the image. In the confocal scanning laser ophthalmoscope this is accomplished by reusing the source optics for detection. The common optical elements are all mirrors-either flat or spherical-and the scanners are positioned to compensate astigmatism due to mirror tilt. The source beam aperture at the horizontal scanner is small. Light returning from the eye is processed by the same elements, but now the polygon's facet is overfilled. A solid-state detector may be at either a pupillary or retinal conjugate plane in the descanned beam and still have proper throughput matching. Our 1-mm avalanche photodiode at a pupillary plane is preceded by interchangeable stops at an image (retinal) plane. Not only can we reject scattered light to a degree unusual for viewing the retina, but we choose selectively among direct and scattered components of the light returning from the eye. One (of many) consequences is that this ophthalmoscope gives crisp and complete retinal images in He-Ne light without dilation of the pupil.

The luminous efficiency of rays entering the eye pupil at different points

1933-03-02

Walter Stiles , B. H. Crawford

The effect to be described in this paper was discovered in attempting to develop an apparatus for measuring the area of the eye pupil, using a photometric principle. The idea … The effect to be described in this paper was discovered in attempting to develop an apparatus for measuring the area of the eye pupil, using a photometric principle. The idea involved is made clear by the diagram fig. 1. The subject applies his eye to the eye-ring E and fixes his eye on the aperture in the diaphragm D. He then sees a photometric field divided into two parts. The lower half is illuminated by light diffused from the opal O, which itself receives light from the lamp S. The rays from this half of the field form a diverging beam which completely fills the pupil of the subject’s eye. The upper half of the field is illuminated by the method of Maxwellian view. An image of the small aperture P is focussed by the lens L on to the middle point of the eye-ring E. This image is only about 1.5 mm. in diameter and all the light is collected by the subject’s eye, provided the pupil of the latter is concentric with the eye-ring and has a diameter exceeding 1.5 mm. A variable graduated neutral wedge W is inserted at the aperture P and this enables the two halves of the photometric field to be adjusted to equality of brightness by the subject.

Retinal Noise and Absolute Threshold

1956-08-01

H. B. Barlow

It is shown that the absorption of one quantum can excite a rod in the human retina, but that at least two, and probably many more, excited rods are needed … It is shown that the absorption of one quantum can excite a rod in the human retina, but that at least two, and probably many more, excited rods are needed to give a sensation of light. It is suggested that noise in the optic pathway limits its sensitivity, and this idea is subjected to an experimental test. The hypothesis is then formulated quantitatively, and shown to be able to account for the above experiment, and also the disagreement in the literature between those who believe that the absorption of two quanta can cause a sensation, and those who believe that 5 or more are required. The formulation of the hypothesis is used to calculate the maximum allowable noise (expressed as a number x of random, independent events confusable with the absorption of a quantum of light) in the optic pathway for the absorption of various fractions of the total number of quanta incident at the cornea.

The Ferrier Lecture, 1962 Visual adaptation

1965-03-16

W. A. H. Rushton

You will need no words of mine to convince you how precious are your eyes, for besides your experience of the incomparable richness that vision brings to human life, you … You will need no words of mine to convince you how precious are your eyes, for besides your experience of the incomparable richness that vision brings to human life, you will reflect that animal life, though clothed in bodies of fantastic diversity can seldom afford to be without sight of a sort, and generally possesses some good visual discrimination. The function of the eye and its nerves is roughly this: to collect light from various places in order to obtain information about rather distant surroundings, to discriminate the patterns of form and movement, and to initiate appropriate reactions. The vertebrate eye, like a photographic camera, collects light with a lens so that a replica of the outside world is formed as an image upon the retina. Here the pattern of light energy is transformed into a pattern of chemical change by the photosensitive pigments of the retinal film. But in the eye (unlike the camera) it is not sufficient for the picture to be ‘taken’ ; it may not lie dormant until it is convenient to develop and appreciate it, for the transmission of information to the brain is often a matter of the greatest urgency. Thus the visual pigment lies not spread in a structureless film but enclosed in a mosaic of active cells, the rods and cones, which constitute the ‘grain’ of the retinal image. Each of these cells can respond to light and give rise to a message that passes towards the brain. By the time the message is taken up by the fibres of the optic nerve we know that it is in the familiar pattern of impulses similar to those in all other long nerves. But we do not know the nature of the complex message transmitted from the rods to the optic nerves.

Laser ablation of human atherosclerotic plaque without adjacent tissue injury

1985-04-01

Warren S. Grundfest , Frank Litvack , James S. Forrester +7 more

Ultrashort Laser Pulse Phenomena

2006-01-01

Jean‐Claude Diels

Laser-based displays: a review

2010-08-04

Kishore V. Chellappan , Erdem Erden , Hakan Ürey

After the invention of lasers, in the past 50 years progress made in laser-based display technology has been very promising, with commercial products awaiting release to the mass market. Compact … After the invention of lasers, in the past 50 years progress made in laser-based display technology has been very promising, with commercial products awaiting release to the mass market. Compact laser systems, such as edge-emitting diodes, vertical-cavity surface-emitting lasers, and optically pumped semiconductor lasers, are suitable candidates for laser-based displays. Laser speckle is an important concern, as it degrades image quality. Typically, one or multiple speckle reduction techniques are employed in laser displays to reduce speckle contrast. Likewise, laser safety issues need to be carefully evaluated in designing laser displays under different usage scenarios. Laser beam shaping using refractive and diffractive components is an integral part of laser displays, and the requirements depend on the source specifications, modulation technique, and the scanning method being employed in the display. A variety of laser-based displays have been reported, and many products such as pico projectors and laser televisions are commercially available already.

Maximum permissible exposures for ocular safety (ANSI 2000), with emphasis on ophthalmic devices

2007-04-11

François C. Delori , Robert H. Webb , David H. Sliney

After discussing the rationale and assumptions of the ANSI Z136.1-2000 Standard for protection of the human eye from laser exposure, we present the concise formulation of the exposure limits expressed … After discussing the rationale and assumptions of the ANSI Z136.1-2000 Standard for protection of the human eye from laser exposure, we present the concise formulation of the exposure limits expressed as maximum permissible radiant exposure (in J/cm2) for light overfilling the pupil. We then translate the Standard to a form that is more practical for typical ophthalmic devices or in vision research situations, implementing the special qualifications of the Standard. The safety limits are then expressed as radiant power (watts) entering the pupil of the eye. Exposure by repetitive pulses is also addressed, as this is frequently employed in ophthalmic applications. Examples are given that will familiarize potential users with this format.

Optical quality of the human eye

1966-10-01

F. W. Campbell , R. W. Gubisch

1. Optical quality of the eye was measured at eight pupil sizes between 1·5 and 6·6 mm diameter by recording the faint light emerging from the eye; this light was … 1. Optical quality of the eye was measured at eight pupil sizes between 1·5 and 6·6 mm diameter by recording the faint light emerging from the eye; this light was reflected from the bright image of a thin line on the fundus. 2. The nature of the fundus reflexion was examined; it was found that the fundus acts very much like a perfect diffuser while retaining polarization. 3. Using the result that the fundus acts like a diffuser, the recorded line images were Fourier analysed to provide modulation transfer functions. These functions indicate an optical quality considerably higher than that found in previous physical studies. 4. Linespread profiles were then derived from the modulation transfer functions. These profiles are 40% narrower than those of previous physical studies for a 3·0 mm pupil. The narrowest profile occurred with a 2·4 mm pupil. 5. Our results demonstrate that physical and psychophysical studies can yield similar estimates of optical quality. The influence of optical factors not common to both techniques is discussed. Evidence for the existence of neural ‘image sharpening’ mechanisms is reviewed.

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The colorimetric properties of the spectrum

1931-09-17

J Guild

Those properties of the eye which determine its behaviour in the measurement of luminous intensity and colour are completely defined by two sets of numerical data which express, as functions … Those properties of the eye which determine its behaviour in the measurement of luminous intensity and colour are completely defined by two sets of numerical data which express, as functions of wave-length, its behaviour to monochromatic radiation throughout the visible spectrum in respect of these two aspects of the visual effect of a stimulus. The first of these functions is embodied in the “ Relative Visibility ”* curve of the spectrum, and the second is embodied in a curve showing the locus of the spectrum on the “ colour triangle ” of some trichromatic system. These two functions may be combined to give the “ mixture curves ” of the spectrum, by means of which we can calculate both the photometric and colorimetric values of any stimulus from its spectral energy distribution. The nature and significance of these various functions are sufficiently well understood to need no explanation here.

Effects of carbon dioxide, Nd-YAG, and argon laser radiation on coronary atheromatous plaques

1982-12-01

George S. Abela , Sigurd J. Normann , Donald M. Cohen +3 more

Perception of Another Person's Looking Behavior

1963-09-01

James J. Gibson , Anne D. Pick

The classical senses in normal use require not only receptors but also muscles for adjusting them. Touching, sniffing and tasting, listening, and above all, looking, involve some degree of motor … The classical senses in normal use require not only receptors but also muscles for adjusting them. Touching, sniffing and tasting, listening, and above all, looking, involve some degree of motor activity. These responses have no effect on the environment, it is true, but they do have an effect on the stimulation which controls behavior. In different ways, they explore the possibilities of stimulation, maximizing, refining, and sharpening its content of information. Focused, stabilized, and appropriately centered retinal images, for instance, are the product of a whole complex of ocular responses which have been recorded and are fairly well understood. The sense-organ adjustments, in short, are a form of observable behavior. The act of visual attention in another person can be perceived simply by watching his face, and we do in fact notice where a person is looking. The act of looking can be treated as a source of stimulation as well as a type of response. The eyes not only look, but are looked at. The direction of a person's gaze usually indicates what object he is interested in or what person he is responding to in the sphere of the environment, and a shift of his fixation may indicate what he is going to do next, as the boxer and the fencer know. The fact of being looked at, that is, a line of gaze fixed on the body of the observer himself, is especially significant.

Ablative photodecomposition: action of far-ultraviolet (193 nm) laser radiation on poly(ethylene terephthalate) films

1982-12-01

R. Srinivasan , William J. Leigh

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAblative photodecomposition: action of far-ultraviolet (193 nm) laser radiation on poly(ethylene terephthalate) filmsR. Srinivasan and W. J. LeighCite this: J. Am. Chem. Soc. 1982, 104, 24, 6784–6785Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAblative photodecomposition: action of far-ultraviolet (193 nm) laser radiation on poly(ethylene terephthalate) filmsR. Srinivasan and W. J. LeighCite this: J. Am. Chem. Soc. 1982, 104, 24, 6784–6785Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https://pubs.acs.org/doi/10.1021/ja00388a052https://doi.org/10.1021/ja00388a052research-articleACS PublicationsRequest reuse permissionsArticle Views620Altmetric-Citations320LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Pulsed CO2 laser tissue ablation: Effect of tissue type and pulse duration on thermal damage

1988-01-01

Joseph T. Walsh , Thomas J. Flotte , R. Rox Anderson +1 more

Abstract Tissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and … Abstract Tissue removal by infrared lasers is accompanied by thermal damage to nonablated tissue. The extent of thermal damage can be controlled by a choice of laser wavelength, irradiance, and exposure duration. The effect of exposure duration has been studied in vivo by using CO 2 lasers with pulse widths that vary from 2 μsec to 50 msec. Pulse widths of 50 msec, typical of a shuttered, continuous‐wave CO 2 laser, produce damage regions 750 μm wide in normal guinea pig skin; the use of a 2‐μseclong pulse reduced this damage zone to as little as 50 μm. Using 2‐μseclong pulses, in vitro studies showed that the minimum zone of thermal damage varied significantly with tissue type. The thermal denaturation of these tissues has been studied and correlated with damage. The effect of denaturation temperature and pulse duration on the width of the damage zone is explained by a simple model.

Visual Pigments in Single Rods and Cones of the Human Retina

1964-04-03

Paul K. Brown , George Wald

Difference spectra of the visual pigments have been measured in single rods and cones of a parafoveal region of the human retina. Rods display an absorption maximum (λ max ) … Difference spectra of the visual pigments have been measured in single rods and cones of a parafoveal region of the human retina. Rods display an absorption maximum (λ max ) at about 505 mμ, associated with rhodopsin. Three kinds of cones were measured: a blue-sensitive cone with λ max about 450 mμ; two green-sensitive cones with λ max about 525 mμ; and a red-sensitive cone with λ max about 555 mμ. These are presumably samples of the three types of cone responsible for human color vision.

Vision with a Stabilized Retinal Image

1952-07-01

R. W. Ditchburn , B. L. Ginsborg

Retinal sensitivity to damage from short wavelength light

1976-03-11

William T. Ham , Harold A. Mueller , David H. Sliney

The directional sensitivity of the retina and the spectral sensitivities of the rods and cones

1939-03-10

Walter Stiles

It is now well established that light rays of the same spectral character and physical intensity entering the eye through different points of the pupil may produce visual impressions which … It is now well established that light rays of the same spectral character and physical intensity entering the eye through different points of the pupil may produce visual impressions which differ in brightness and colour even though the patch of retina stimulated (the fovea) is kept the same. Rays entering the eye through different points of the pupil and terminating on the same point of the retina are incident on the retina in different directions. Also, they have traversed different paths in the refractive media of the eye and may have suffered different losses by absorption, scattering or reflexion. It has been shown, however, that differences in the light losses in the refractive media do not account for the observed variations in visual response, which must therefore be attributed to variations in the reaction of the retina to light incident on it in different directions or, briefly, to a directional sensitivity of the retina. Further evidence that this is so is given later in the paper (p. 81).

�ber die Streuung von Licht an Licht nach der Diracschen Theorie

1935-04-01

H. Euler , B. Kockel

The Sensitivity Performance of the Human Eye on an Absolute Scale*

1948-02-01

Albert Rose

An absolute scale of performance is set up in terms of the performance of an ideal picture pickup device, that is, one limited only by random fluctuations in the primary … An absolute scale of performance is set up in terms of the performance of an ideal picture pickup device, that is, one limited only by random fluctuations in the primary photo process. Only one parameter, the quantum efficiency of the primary photo process, locates position on this scale. The characteristic equation for the performance of an ideal device has the form BC2α2=constantwhere B is the luminance of the scene, and C and α are respectively the threshold contrast and angular size of a test object in the scene. This ideal type of performance is shown to be satisfied by a simple experimental television pickup arrangement. By means of the arrangement, two parameters, storage time of the eye and threshold signal-to-noise ratio are determined to be 0.2 seconds and five respectively. Published data on the performance of the eye are compared with ideal performance. In the ranges of B(10−6 to 102 footlamberts), C(2 to 100 percent) and α(2′ to 100′), the performance of the eye may be matched by an ideal device having a quantum efficiency of 5 percent at low lights and 0.5 percent at high lights. This is of considerable technical importance in simplifying the analysis of problems involving comparisons of the performance of the eye and man-made devices. To the extent that independent measurements of the quantum efficiency of the eye confirm the values (0.5 percent to 5.0 percent), the performance of the eye is limited by fluctuations in the primary photo process. To the same extent, other mechanisms for describing the eye that do not take these fluctuations into account are ruled out. It is argued that the phenomenon of dark adaptation can be ascribed only in small part to the primary photo-process and must be mainly controlled by a variable gain mechanism located between the primary photo-process and the nerve fibers carrying pulses to the brain.

The thermal response of laser irradiated tissue

1984-12-01

A. Welch

The extent of thermal destruction of tissue by visible and near-infrared lasers is governed by heat deposition in the tissue, heat transfer, and temperature-dependent rate reactions. Often the thermal response … The extent of thermal destruction of tissue by visible and near-infrared lasers is governed by heat deposition in the tissue, heat transfer, and temperature-dependent rate reactions. Often the thermal response has been analyzed by linear models with constant coefficients that presume exponential absorption of the laser irradiation with depth. However, for weakly absorbing tissues, light scattering dominates the optical properties. These properties may be altered by thermal damage of the tissue. Also, thermal properties for tissue vary with temperature and water content. Typical therapeutic laser irradiations vaporize water in the tissue causing sharp increases in temperature beyond 100°C, and continued irradiation causes ablation of the tissue. Models for all these events are discussed.

Beiträge zur Theorie des statischen und des dynamischen Lichtbogens

1943-12-01

Otto Mayr

A first-order model for computation of laser-induced breakdown thresholds in ocular and aqueous media. I. Theory

1995-01-01

Paul K. Kennedy

An analytic, first-order model has been developed to calculate irradiance thresholds for laser-induced breakdown (LIB) in condensed media, including ocular and aqueous media. The model is derived from the simple … An analytic, first-order model has been developed to calculate irradiance thresholds for laser-induced breakdown (LIB) in condensed media, including ocular and aqueous media. The model is derived from the simple rate equation formalism of Shen for cascade breakdown in solids and from the theory of multiphoton ionization in condensed media developed by Keldysh. Analytic expressions have been obtained for the irradiance thresholds corresponding to multiphoton breakdown, to cascade breakdown, and to initiation of cascade breakdown by multiphoton ionization of seed electrons (multiphoton initiation threshold). The model has been incorporated into a computer code and code results compared to experimentally measured irradiance thresholds for breakdown of ocular and aqueous media by nanosecond, picosecond, and femtosecond laser pulses in the visible and near-infrared. The code and comparison of code results to experiment have been documented in part II.

Contrast Thresholds of the Human Eye

1946-11-01

H. Richard Blackwell

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text H. … Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text H. Richard Blackwell, "Contrast Thresholds of the Human Eye," J. Opt. Soc. Am. 36, 624-643 (1946) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Laser speckle and related phenomena

1984-12-01

B. Roy Frieden

Visual acuity in the presence of retinal-image motion*

1975-07-01

Gerald Westheimer , Suzanne P. McKee

Resolution thresholds for Landolt C's and for vernier targets remain the same whether the target is stationary or moving with horizontal or vertical velocities of up to 2.5°/s for foveal … Resolution thresholds for Landolt C's and for vernier targets remain the same whether the target is stationary or moving with horizontal or vertical velocities of up to 2.5°/s for foveal presentations lasting 0.1 and 0.2 s. Oblique target motions are tolerated only up to 1°/s. Because visual pursuit is ruled out by randomization of direction of motion and by the short exposure, it is concluded that a stationary retinal image is not a prerequisite for good acuity.

Zum Einfluß der Spaltbreite auf die Intensitätsverteilung in Spektrallinien. II

1931-05-01

P. H. van Cittert

THE INTERPRETATION OF SPECTRAL SENSITIVITY CURVES

1953-01-01

H. J. A. Dartnall

Journal Article THE INTERPRETATION OF SPECTRAL SENSITIVITY CURVES Get access H. J. A. DARTNALL, B.Sc. Ph.D. F.R.I.C. H. J. A. DARTNALL, B.Sc. Ph.D. F.R.I.C. Medical Research Council Group for Research … Journal Article THE INTERPRETATION OF SPECTRAL SENSITIVITY CURVES Get access H. J. A. DARTNALL, B.Sc. Ph.D. F.R.I.C. H. J. A. DARTNALL, B.Sc. Ph.D. F.R.I.C. Medical Research Council Group for Research in the Physiology of Vision Institute of OphthalmologyLondon Search for other works by this author on: Oxford Academic PubMed Google Scholar British Medical Bulletin, Volume 9, Issue 1, 1953, Pages 24–30, https://doi.org/10.1093/oxfordjournals.bmb.a074302 Published: 01 January 1953

Safety with Lasers and Other Optical Sources

1980-01-01

David H. Sliney , Myron L. Wolbarsht

Laser light scattering: Basic principles and practice

1992-09-01

Raymond D. Mountain

American National Standard for the Safe Use of Lasers.

1975-01-01

Laser Light Scattering

1991-01-01

Laser Light Scattering

1970-10-01

Benjamin Chu

Laser Speckle and Related Phenomena

1975-01-01

John Christopher Dainty , Anthony Edward Ennos , Maurice Françon +3 more

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Vision and Visual Dysfunction

1991-01-01

J Cronly‐Dillon

This is an index covering all 16 volumes of an encyclopedia on vision covering all research aspects of this mutidisciplinary field by 300 contributors from around the world. Each volume … This is an index covering all 16 volumes of an encyclopedia on vision covering all research aspects of this mutidisciplinary field by 300 contributors from around the world. Each volume is extensively referenced, illustrated and indexed. The articles relate the current state of our knowledge and areas of continuing advancement and will be updated in additional volumes every five years. It is aimed at libraries in all universities, relevant departments and other insitutions conducting research into vision, medical schools and relevant major industrial concerns such as pharmaceutical, optics and robotics companies.

Effects of High-Power Laser Radiation

1971-01-01

John F. Ready

A real world attack model combining LED modulation and attention-superpixel guidance

2025-06-23

You Jiang , Yuqiao Luo , Junbin Fang +7 more | Expert Systems with Applications

Case of macular hole caused by intense pulsed light

2025-06-18

X. Wang , Wei-Jiang Xü , Fang Jia hao +1 more | Research Square (Research Square)

<title>Abstract</title> <bold>BACKGROUND: </bold>Intense pulsed light is widely used in cosmetic techniques. When IPL is flashed into people’s eyes, it can be dangerous and cause serious eye damage. <bold>Case presentation: </bold>A … <title>Abstract</title> <bold>BACKGROUND: </bold>Intense pulsed light is widely used in cosmetic techniques. When IPL is flashed into people’s eyes, it can be dangerous and cause serious eye damage. <bold>Case presentation: </bold>A 30-year-old male patient suffered an 808±10 nm IPL injury to his eye. One week after the injury, the patient’s peripheral residual best-corrected visual acuity in the right eye was 20/200 with a refractive power of −4.00/−0.25×20=0.1. Optical coherence tomography (OCT) showed a full macular tear. The patient underwent vitrectomy, inner border membrane stripping and sterile air injection 1 month after injury. OCT showed fissure closure 1 week after surgery. However, his best-corrected visual acuity did not improve at 1-month post-operative follow-up. <bold>CONCLUSION: </bold>This case report is comprehensive.

Recognizing red flags in children

2025-06-18

Cayetano García-Castrillón Armengou | Routledge eBooks

Continuous flashing suppression of V1 responses and the perceptual consequences revealed via two-photon calcium imaging and transformer modeling

2025-06-14

Cai-Xia Chen , Xin Wang , Dan-Qing Jiang +2 more | bioRxiv (Cold Spring Harbor Laboratory)

Continuous flash suppression (CFS), where a dynamic masker presented to one eye suppresses the conscious perception of a stimulus shown to the other eye, has been extensively used to study … Continuous flash suppression (CFS), where a dynamic masker presented to one eye suppresses the conscious perception of a stimulus shown to the other eye, has been extensively used to study visual consciousness. Various studies reported high-level visual and cognitive functions under CFS, which, however, has more recently been questioned and at least partially attributed to low-level stimulus. A key but unsettled issue is the extent to which the responses of V1 neurons, where inputs from two eyes first merge, are affected, as severely suppressed V1 responses would not sustain high-level processing. Here, we used two-photon calcium imaging to record the responses of V1 neurons to a grating stimulus under CFS in awake, fixating macaques. The results revealed that CFS substantially suppressed V1 orientation responses. Ocularity-wise, it nearly completely eliminated the orientation responses of V1 neurons preferring the masker eye or both eyes, while also significantly suppressing the responses of those preferring the grating eye. Modeling analyses suggest that, under CFS, the brain retains the ability of classifying coarse orientations, but may become less capable of reconstructing the grating stimulus. Consequently, while CFS-suppressed orientation information still supports low-level orientation discrimination, it may not suffice for high-level visual and cognitive processing.

Laser safety in dental practice in the United Kingdom

2025-06-13

Steven Parker , Mark Cronshaw | BDJ

Asymmetric and Eccentric Laser Pointer Maculopathy in a Teenager

2025-06-13

Maria Krisch , Jordan A. Ueberroth , Mark P. Breazzano | Journal of Ophthalmic and Vision Research

This is a Photo Essay and does not have an abstract. Please download the PDF or view the article in HTML. This is a Photo Essay and does not have an abstract. Please download the PDF or view the article in HTML.

CRR visuell

2025-06-05

| Schäffer-Poeschel eBooks

Die mehr als 500 Artikel umfassende CRR-Verordnung umfasst insbesondere Regelungen zu den Bestandteilen der Eigenmittel, Eigenmittelanforderungen, Großkrediten, Berichterstattung zur Liquidität, Verschuldung und Offenlegung. Die grafische Darstellung ermöglicht einen schnellen Zugang … Die mehr als 500 Artikel umfassende CRR-Verordnung umfasst insbesondere Regelungen zu den Bestandteilen der Eigenmittel, Eigenmittelanforderungen, Großkrediten, Berichterstattung zur Liquidität, Verschuldung und Offenlegung. Die grafische Darstellung ermöglicht einen schnellen Zugang zu dem komplexen Regelwerk. Darüber hinaus sind diejenigen Änderungen besonders hervorgehoben, die sich auf die nationalen Bestimmungen beziehen, im Wesentlichen das KWG, die SolvV sowie die GroMiKV. Mit Einführung in jeden Themenbereich und hilfreichen Anhängen, wie z.B. einer Übersicht über die Begriffsbestimmungen der CRR und einer Übersicht der an die EBA gerichteten Arbeitsaufträge. Die 4. Auflage berücksichtigt die neuen Regelungen der CRR III, welche zum 1.1.2025 zur Anwendung kommen.

A swept-source optical coherence tomography study of the spectrum of laser pointer maculopathy

2025-06-05

Magdy Moussa , M. Leila , Mohammed Elashri +1 more | International Journal of Retina and Vitreous

Abstract Background To evaluate the efficacy of swept-source optical coherence tomography (SS-OCT) in detecting the clinical spectrum of macular microstructure changes secondary to laser pointer injury (LPI), including their response … Abstract Background To evaluate the efficacy of swept-source optical coherence tomography (SS-OCT) in detecting the clinical spectrum of macular microstructure changes secondary to laser pointer injury (LPI), including their response to therapeutic intervention. Methods: A retrospective study, including consecutive patients with LPI. Inclusion criteria were visual symptoms and biomicroscopic, OCT, and fundus fluorescein angiography (FFA) features of LPI. We used the SS-OCT for imaging and the swept-source optical coherence tomography angiography (SS-OCTA) to confirm or exclude the diagnosis of a choroidal neovascular membrane (CNV). We used FFA to confirm the diagnosis of a CNV whenever SS-OCT and SS-OCTA images were insufficient to establish its presence. The outcome measures were the morphological features in the macula secondary to LPI and the response of CNV to aflibercept. Results: The study included 31 eyes of 22 patients. Ten patients (45%) were ≤ 15 years old. Laser pointer maculopathy (LPM) was bilateral in 9 patients (41%). The mode of injury was self-inflicted in 14 patients (64%). Central scotoma was the most common symptom reported by the patients. The mean baseline best-corrected visual acuity (BCVA) was 20/50. The mean follow-up period was 9.6 months. The mean final BCVA was 20/40. Acute stages of LPM were characterized by focal or diffuse disruption of the outer retinal layers, subretinal hyperreflective mound, anvil-shaped lesion, or the angular sign of Henle fiber layer hyperreflectivity (ASHH). The features of chronic stages included secondary CNV or macular holes. CNV and macular hole were common features in both acute and chronic stages. The most common LPI-induced macular lesion was retinal pigment epithelium (RPE) changes. Type II CNV developed in three eyes (10%). Conclusion: SS-OCT depicted a characteristic morphological profile of LPM in the acute and chronic stages. SS-OCTA is a non-invasive and reproducible complementary tool in detecting secondary CNV and monitoring its response to therapy.

Damage capability of laser system in ground-air defense environments

2025-06-01

Wei Liu , Lin Zhang , Wenfeng Wang +4 more | Chinese Journal of Aeronautics

Beyond The Laser

2025-05-31

| Machinery

Adam Ball, UK Operations Director at Lantek, discusses how sheet metal manufacturers are addressing the challenges of increased competition through extending their services and including advanced software systems Adam Ball, UK Operations Director at Lantek, discusses how sheet metal manufacturers are addressing the challenges of increased competition through extending their services and including advanced software systems

ECgo: All-Optical Induction of Single Endothelial Cell Injury and Capillary Occlusion in the Brain

2025-05-30

Jacqueline Condrau , Srinivasarao Allu , Tatiana V. Esipova +7 more | bioRxiv (Cold Spring Harbor Laboratory)

The ability to induce endothelial cell (EC) damage in the mouse brain with high spatial precision is invaluable for mechanistic studies of brain capillary injury and repair. Here, we introduce … The ability to induce endothelial cell (EC) damage in the mouse brain with high spatial precision is invaluable for mechanistic studies of brain capillary injury and repair. Here, we introduce an optical method, termed ECgo, that utilizes a new two-photon-excitable porphyrin-based photosensitizer (Ps2P) to selectively obliterate single ECs within the brain microvascular network. Using the developed approach, we were able to induce occlusions of single capillaries with high spatiotemporal control, while preserving the surrounding tissue. Combined with longitudinal two-photon imaging, ECgo enables studies of morphological and functional consequences of targeted single capillary EC injury in vivo under healthy and diseased conditions.

Pseudoexfoliative Deposits on an Implantable Collamer Lens

2025-05-30

Young Hoon Hwang | Korean Journal of Ophthalmology

Light after loss

2025-05-29

Katya Provornaya | Routledge eBooks

The Effects of Nonplanar Cloud Top on Lightning Optical Observations from Space-Based Instruments

2025-05-29

Bingzhe Dai , Qilin Zhang , Xiaole Pan | Atmosphere

Satellite optical observations of lightning are influenced by a variety of factors. Studying these factors can provide valuable reference information for applications such as lightning parameter inversion. However, due to … Satellite optical observations of lightning are influenced by a variety of factors. Studying these factors can provide valuable reference information for applications such as lightning parameter inversion. However, due to the variability of natural factors and the high cost of field observations, research requiring controlled variables often relies heavily on effective simulation models. To this end, we applied our developed optical transmission model for lightning, which can simultaneously account for the spatiotemporal characteristics of lightning sources and observation angles, as well as inhomogeneous and irregular cloud environments, to analyze an unexplained hypothesis from previous studies—that non-planar cloud tops may also be an influencing factor. Our analysis confirms that non-planar cloud tops are indeed an important factor that must be considered, especially under smaller or larger observation angles. In the simulation results, undulations caused an energy increase of up to 43.19% at a 0° observation angle, while at a 60° observation angle, the undulations resulted in an additional attenuation of approximately 17.5%.

Multimodal imaging of dark without pressure in high myopia reveals evidence that photoreceptor microscopic lesions may be reversible

2025-05-29

Qingge Guo , Xiuxiu Jin , Xiaoyu Xin +4 more | Scientific Reports

Dark without pressure (DWP) is the more darkly pigmented area of the retina in the fundus, typically exhibits relatively distinct boundaries, and varies in shape, size, and distribution across different … Dark without pressure (DWP) is the more darkly pigmented area of the retina in the fundus, typically exhibits relatively distinct boundaries, and varies in shape, size, and distribution across different individuals. Previous studies have concluded that DWP alone has no impact visual acuity, visual field, or other visual functions. This study aims to reveal the multimodal imaging manifestations of DWP in high myopia and to explore its impact on retinal function. This is a prospective study. Eleven high myopia patients with DWP were recruited. Detailed ophthalmological examinations, such as visual acuity, intraocular pressure, slit lamp microscope, and fundoscopy, were performed in all participants to exclude other ocular diseases or retinopathies. Multimodal imaging including swept source optical coherence tomography (SS-OCT), adaptive optics (AO) fundus imaging was applied to analyze morphologic manifestations of DWP. Retinal photosensitivity was detected by perimetry or microperimetry. Eight of the participants were followed for at least 5 months and up to 32 months. The DWP appeared as water trace pattern that was darker in color than the surrounding normal fundus. The punctate light reflectivity of the photoreceptor mosaic in AO fundus imaging was missing, and the light reflectivity in ellipsoid zone (EZ) of SS-OCT B scan was attenuated or even disappeared simultaneously. Perimetry revealed reduced retinal photosensitivity in the DWP lesions. At 5-month follow-up, the area of DWP lesions could appear to expand or shrink. Where the DWP faded away, the reflectivity of EZ on SS-OCT returned to normal hyperreflectivity, accompanied with a recovered retinal photosensitivity. The imaging basis for DWP in high myopia is the presence of microscopic lesions in the outer retina which could be shown morphologically with optical imaging and functionally with microperimetry. It is variable in size and may be reversible in function in the fundus.

Ocular cues to a larger picture!

2025-05-28

Aruja Gangwani , Meghna Ganesh , Vinod Kumar | Indian Journal of Ophthalmology

Bothersome hot flashes following relugolix and stereotactic body radiotherapy for localized prostate cancer.

2025-05-28

Sukhjeevan Nijhar , Sarthak Shah , Srinivas Sowmiyanarayanan +7 more | Journal of Clinical Oncology

e17087 Background: Androgen deprivation therapy (ADT) has been shown to improve cancer control when combined with radiation therapy. Relugolix is an oral GnRH receptor antagonist that achieves rapid profound testosterone … e17087 Background: Androgen deprivation therapy (ADT) has been shown to improve cancer control when combined with radiation therapy. Relugolix is an oral GnRH receptor antagonist that achieves rapid profound testosterone suppression. ADT cause several hormonally related symptoms that resolve with testosterone recovery. Hot flashes are particularly bothersome. This prospective study sought to evaluate the timeline of hot flashes following initiation of a short course of Relugolix and stereotactic body radiotherapy (SBRT) for unfavorable localized prostate cancer. Methods: Institutional IRB (IRB #12-1775) approval was obtained for retrospective review of prospectively collected data. Patients were treated at Georgetown between per an institutional protocol. Hot flashes were self-reported via question 13a of the Expanded Prostate Index Composite (EPIC)-26 prior to ADT initiation, the first day of SBRT, and at each follow-up (1-, 3-, 6-, 9-, and 12-months). The responses were grouped into three relevant categories (no problem, very small-small problem and moderate to big problem). Scores were transformed to a 0-100 scale with higher scores reflecting less bother. All patients were treated with the robotic SBRT (Accuray). Total Testosterone levels were measured at each follow-up. Items were evaluated for statistical significance (paired t-test, p <0.05) and clinical significance (minimally important difference (MID); 0.5 standard deviation from baseline). Results: 89 localized prostate cancer patients (20 intermediate risk, 63 high risk, and 6 recurrent) at a median age of 71.5 years (range 49-89 years) who were treated with prostate SBRT (35-36.35 Gy) and a course relugolix of average length of 6.25 months (range 3-29 months) from January 2021 to September 2023 at a single institution were included in this study. Thirty seven percent were non-white and 24% were obese. Patients initiated relugolix a median of 3 months (range, 0-11) prior to SBRT and completed relugolix a median of 2 months (range, 0-36 months) post-SBRT. Prior to relugolix initiation, 1.3% of men reported hot flashes that were a moderate to big problem. That proportion peaked at 1-month post-SBRT (46.2%) before returning to baseline at 9 months post-SBRT (0%) with a cumulative incidence of 57%. The median baseline EPIC-26 hot flash score of 98.7 declined to 49.0 at 1-month post-SBRT and returned to baseline by 9-months post-SBRT. These differences were statistically (P < 0.01) and clinically significant (MCID = 98.8 +/- 4.45). Testosterone recovery (> 230 ng/dL) occurred in 97% of patients 12 months post-SBRT. Conclusions: Bothersome hot flashes occur in greater than 50% of men treated with short course relugolix and SBRT. Resolution of hot flashes occurs in the majority of men by 9 months post SBRT. Hot flash resolution mirrored testosterone recovery. Reassurance of the temporary nature of hot flashes may reduce patient anxiety and limit associated bother.

Fabricating Polydimethylsiloxane (PDMS) Human Dermal Phantoms with Predominant Scattering and Tunable Properties Across 900 to 1350 nm

2025-05-27

Oluwadamilola Oke , Jason M. Zara

Perfil inflamatorio del humor acuoso tras tratamiento asistido por láser de femtosegundo en casos de catarata nuclear

2025-05-26

Claudia Palacio-Pastrana , Andric C. Perez‐Ortiz , Bani Antonio‐Aguirre +5 more

These contact lenses let humans see invisible infrared light

2025-05-23

Elizabeth Gibney , Shamini Bundell

A new perspective on the optical Vernier effect and its apparent sensitivity enhancement

2025-05-22

Paulo Robalinho , Vinícius Piaia , A. Ribeiro +2 more

Feature extraction of disturbance signal based on Hilbert-Huang transform for event recognition of Φ-OTDR

2025-05-22

Yi Huang , Ziyi Wei , Yi Zhang +7 more

Camera-based security system featured with laser detection and warning

2025-05-22

Do Tri Nhut , Tran Huu Duat

Recent advancements in camera-based technologies have heightened security demands across various sectors. Cameras now play a pivotal role in traffic management, disease screening, industrial automation, and facial recognition. Nonetheless, many … Recent advancements in camera-based technologies have heightened security demands across various sectors. Cameras now play a pivotal role in traffic management, disease screening, industrial automation, and facial recognition. Nonetheless, many existing solutions are prohibitively expensive and complex, limiting the accessibility for broader applications. This paper introduces an innovative, low-cost, and compact security system utilizing the ESP32-CAM kit, which integrates a microcontroller with a built-in camera and Wi-Fi . Our system is engineered to detect unauthorized individuals in residential settings and parking facilities, employing a laser sensor to trigger alerts via a buzzer and capture photographic evidence for subsequent analysis. Anomalies identified by the system are seamlessly transmitted to cloud storage over Wi-Fi, ensuring real-time monitoring and response. Designed for easy installation and affordability, our system holds significant promise for enhancing security in homes and public areas. Through comprehensive experiments and evaluations, we validate the system's feasibility and effectiveness, demonstrating its potential as a transformative solution in the security landscape.

These contact lenses give people infrared vision — even with their eyes shut

2025-05-22

Elizabeth Gibney

ISOSNet: A Unified Framework for Cone Photoreceptor Detection and Inner Segment and Outer Segment Length Measurement from AO-OCT B-scans

2025-05-22

Mengxi Zhou , Yue Zhang , Eli Kirkendall +7 more

Semiconductor Laser Power Supply Control System Based on Improved Algorithm

2025-05-21

Ze Gu , Ermei Yan , Zongyu Zhang

Data protection, quantum messaging, and optical networking all make use of chaos light, a type of technique that improves key transfer safety. Its growth is aided by renewable energy supplies … Data protection, quantum messaging, and optical networking all make use of chaos light, a type of technique that improves key transfer safety. Its growth is aided by renewable energy supplies like semiconductor lasers (SLs). To address the insufficient quality of chaos light generation in SL structures, this study developed a linear self-disturbance rejection control-based power regulation methodology. A novel multi-task nutcracker optimization (MTNO) strategy for chaotic optical efficiency improvement is proposed. These findings verified that the resonant converter’s reaction rate increased with the controller’s bandwidth, although its stability is inadequate. The controller strategy’s current ripple factor is reduced while the input voltage fluctuates suddenly. Although the directional selection technique provides helpful choices for sudden fluctuations in load, the suggested control technique guarantees steady voltage and current conditions. The suggested MTNO approach has some advantageous implications for privacy in communication and performs well when used to optimize chaotic optical efficiency.