bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Lenslet Arrays for Pattern Recognition with Polychromatic Light.
Authors: Katzir Yigal , Glaser I. , Menaker Mina
Published: February 2023

Nature, when looking for an 'optimal' imaging system, could not find a single, good for everything, solution. Both single aperture (like the human eye) and multiple aperture (like the eyes of insects) systems are widely used by nature. Originally, the compound eye of insects was thought to be an array of collimators, each being composed of one lenslet and one detector/nerve-ending. As each "collimator" points at slightly different direction, the complete array samples the visual field and forms its image. More recently it was found that, at least for some insects, there is more than one detector per lenslet. This multiple detector/lenslet structure with its nerve network is now believed to provide some image pre-processing at the sensor level of some insects visual system [1]. Man made devices that provide very compact structure with relatively large image were demonstrated [2], [3]. The real potential of multiple aperture optical systems, however, is in providing optical pre-processing, relieving the electronic processor of image processing systems from the computation-intensive part of its work.
Real-Time Extended Range Interferometry
Authors: Strand Timothy C. , Mueller Ernst
Published: February 2023

Although interferometry is an essential tool for measuring distances or phase differences on the order of a wavelength or less, it is hampered in its applicability by a limited measurement range. This range is typically limited to λ/2 where λ is the center wavelength of the illumination source. There are many applications such as profilometry, displacement measurement and wavefront sensing, where measurements must be made over a range of many wavelengths. In these cases, the interferometer output must be processed in order to obtain the required range. However, the required processing is generally time consuming, precluding real-time measurements. We propose a new technique which allows real-time, unambiguous measurement over a range of many wavelengths.
Speckle interferometry techniques for motion sensing
Authors: Creath Katherine
Published: February 2023

Digital speckle pattern interferometry (DSPI) is a means of nondestructively testing mechanical parts. This technique is very versatile, and may be used in many different ways. Applications of this testing technique include the observation and detection of object defects due to stress or strain in the part, out-of-plane object displacement, observation of resonant vibrations, and the quantitative phase mapping of object defects. Comparisons between a master part and a test part can also be performed to determine if it meets specifications. The measurement range of this technique is limited by the wavelength of light used and the number of resolution elements across the object. The limit to the range of motion measureable by DSPI is fifty waves in optical path or twenty-five waves in object movement when using a 100 x 100 element detector array. Larger departures can be measured by processing data from either two-wavelength or two-angle measurements. These last two techniques may also be used for contouring optically deep objects.
Extraction of Polygonal faces in Range Images
Authors: Groshong Bennett , Snyder Wesley
Published: February 2023

A project has been underway for several months at North Carolina State University concerning the identification of objects in range images. A range image is a two dimensional array of numbers in which each number represents, not the brightness at a point, but rather the distance to that point. From such an image, the three dimensional position of each visible surface point may be computed.
A Robot Eye with a Large Holographic Memory
Authors: Liu H. K.
Published: February 2023

It is well-known that advanced automation systems can handle many sophisticated, dangerous, and beyond-the-reach-of-human jobs in the fields of industry, agriculture, deep ocean, outer space, and national defense. For example, in the Mars sample return (MSR) mission1 of the Planetary Spacecraft System Technology of NASA, a high degree of automation is demanded. In addition to artificial intelligence, guidance, control, and aerodynamic technologies in the MSR mission, advance sensors are required for the automated rendezvous and docking system as well as the Mars Rover.
Future Directions in Machine Vision
Authors: Rosenfeld Azriel
Published: February 2023

This paper will give some important examples of recent and anticipated progress in computer vision, including low-level (two-dimensional), intermediate-level (2½- and 3-dimensional), and high-level (goal-directed) techniques.
Silhouette Recognition with Local Constraints
Authors: Van Hove Patrick
Published: February 2023

In this paper, an experimental model-based vision system recognizing silhouettes of 3-D objects is described. The system uses local constraints to prune a tree of pairings between image features and model features, then performs a complete verification for each remaining hypothesis. Recognition based on local constraints has been reported by Grimson and Lozano-Perez for matching 2-D measurements to 2-D models, and for matching 3-D measurements to 3-D models [1]. The system described in this paper matches 2-D silhouette measurements to 3-D object models.
Correspondence from Correspondence
Authors: Aloimonos John (Yian-nis) , Kamgar-Parsi Behrooz
Published: February 2023

Image matching (or registration) is, in general terms, aligning two identical or similar images or parts of images, and it is basic to a number of vision problems. These include optical navigation (also known as motion analysis), stereo image interpretation, object analysis, change detection and others. The difficult part of all these problems, is the matching problem, i.e. the computation of the correspondence of elements in the different views. The computation of correspondence, in both the stereo and the motion problem, is impossible without the use of some assumptions about the visual world and various researchers have proposed several theories for the computation of visual correspondence that worked well for the domains that fitted their assumptions. In this paper we study the problem of the computation of visual correspondence, under the assumption that some values of the correspondence function are already known and we develop the mathematical constraints that are needed for growing a solution for the correspondence function from points where its value is known. In other words, since the problem of determining visual correspondence has proven to be very difficult, we attempt to solve a simplified version of it, i.e. the case where we already know the values of the correspondence for some points. This assumption is not very restrictive, since in several practical situations prominent features could be used to easily find the correspondence of some points.
Laser requirements on active tracking
Authors: Riker Jim F. , Merritt Paul , Roark J.T.
Published: February 2023

In this paper, we will review the requirements on laser power and beam quality for active tracking of missiles and satellites. We will compare the cases of solar illumination and laser illumination from a theoretical and also simulation standpoint, and we will show results obtained from Starfire Optical Range and White Sands Missile Range using active tracking lasers. The potential benefits for active tracking include full sky coverage for orbiting debris, laser ranging for ephemeris updating, and precision tracking for boosting missiles. Other aspects of the laser requirements will also be presented, including the impacts of speckle and jitter coupling.
Beam Profile Monitoring of Synchrotron Radiation by Adaptive Optics
Authors: Takeuchi N. , Mitsuhashi T. , Itoh M. , Yatagai T.
Published: February 2023

A beam profile monitor system for the synchrotron radiation was designed to evaluate distribution of cross section of the electron in high energy accelerator storage ring. The Shack-Hartmann wavefront sensor was designed and constructed for a measurement of wavefront error caused by a deformation of an extraction beryllium mirror for the visible synchrotron radiation. An adaptive optical system was designed for this monitor to correct wavefront distortion.
Laser ablative figuring of optics for phase control
Authors: Jitsuno Takahisa , Tokumura Keiu , Akashi Tomoyoshi , Nakatsuka Masahiro
Published: February 2023

In the fabrication procedure of precise optics, the control of the phase distribution of the optics was difficult task because the previous fabrication method was not suitable for the figuring of surface profile. Furthermore, since the previous fabrication was not made on the interferometer, the measurement of the phase distribution was made off-line scheme. We have proposed a novel method for figuring the surface profile of optical plastics and optical glass using very short wavelength excimer laser1). We used ArF laser (λ=193 nm) because the shorter wavelength laser light provides the smoother surface2). We have made some basic experiments on the measurement of the ablation rate of different kinds of optical plastics (PMMA) and optical glass (BK-7) in situ interferometric observation of the surface figure.
Adaptive Optics Using A Liquid Crystal Phase Modulator in Conjunction With a Shack-Hartmann Wave-Front Sensor
Authors: Dayton David , Browne Steve , Gonglewski John , Sandven Steve
Published: February 2023

Multi-segment spatial light modulators (SLM) have recently received much attention for use in adaptive optics applications.1 These devices have the advantage that they are compact, light weight, and less expensive than deformable mirrors. They can also be used in transmission. These attributes make them desirable for use in many applications including those not associated with astronomy. At present the devices are some what slow; however, it is envisioned that their speed will be increased considerably in the near future.
A Prototype - Stimulator for Localized Electroperimetry
Authors: Fonda S. , Baraldi P.
Published: February 2023

Neuro-ophthalmological diagnostics needs an objective methodology that perimits one to obtain information about the integrity of the peripheral nervous visual pathway. The recording of visual evoked response at retinal or cortical levels by localized stimuli on the retinal periphery has been performed for a long time1 but electrophysiological measurements using the visual evoked potentials (VEP) gives data up to 10° eccentricity only.2
Multi-Flash Campimetry as an Indicator of Visual Field Loss in Glaucoma
Authors: Brussell Edward M. , Overbury Olga , White Charles W. , Balazsi Gordon A.
Published: February 2023

Ocular hypertension (OHT), or elevated pressure in the ocular media, is a condition that is closely monitored by the ophthalmologist. The reason is that it can lead to irreversible visual field loss at which time the diagnosis is changed from OHT to glaucoma. Field losses that are observed are usually attributed to ischemia (1) and mechanical pressure (2, 3) at the optic disk. More recently, however, Regan and his colleagues have suggested that there may also be ganglion cell dendritic pathology associated with OHT that is accompanied by visual loss to which conventional perimetry is not sensitive (4,5). In particular, the dendritic pathology may affect temporal (i.e. , flicker) more than spatial aspects of vision.
Predicting Low-Vision Reading Rates from Measures of Contrast Sensitivity*
Authors: Rubin Gary S. , Legge Gordon E.
Published: February 2023

The National Society for the Prevention of Blindness has estimated that about two million Americans have severely impaired vision. Most of these individuals can read normal print if magnification and other viewing conditions are suitable. However, few general principles exist to guide the design or prescription of low-vision reading aids. This is because we don't know the stimulus conditions that are required for optimal reading by people having various types and degrees of vision loss, and we are unable to predict the best performance these people might achieve.
The Acuity Card Procedure: Rapid Clinical Assessment of Visual Acuity in Infants and Non-Verbal Patients
Authors: Preston Karen L. , Teller Davida Y.
Published: February 2023

The acuity card procedure1 is a recently developed variation of preferential looking (PL) for use in the behavioral assessment of the visual acuity of infants and young children. The procedure is suitable for use in clinical settings because it is fast, accurate, and may be used across a wide range of ages to assess the acuity of patients with diverse clinical disorders. The purpose of this paper is to introduce the acuity card procedure to clinical psychophysicists and invite discussion of the potential usefulness of the cards in routine clinical application.
Two-color increment thresholds in early age-related maculopathy
Authors: Haegerstrom-Portnoy G. , Brown B.
Published: February 2023

Age-related maculopathy (ARM) also referred to as senile macular degeneration (SMD) is one of the most common eye diseases in the western world, particularly among older persons. The clinical signs include reduced visual acuity, alterations in color vision and central visual field loss in the advanced stages of the disease. The most commonly reported color vision defect is a blue-yellow defect found on tests such as the AO HRR plate test, the D15 and the FM 100 Hue test (Campbell and Rittler, 1972; Francois and Verriest, 1968)
Full-field Cone ERGs and VERs recorded simultaneously
Authors: Gouras P. , MacKay C. , Brittis M.
Published: February 2023

The human electroretinogram (ERG) and visually evoked (cortical) response (VER) have been examined with full field spectrally selective (chromatic) flashes on a steady yellow adapting full-field. The flash frequency is 3 Hz and many responses to the same flash are averaged to enhance the signal to noise ratio. The ERG is detected with a bipolar contact lens, which contacts the cornea with one lead and the adjacent conjunctiva with the other. The VER is recorded between the center of the forehead and the inion. The latter lead also detects the ERG but at a lower amplitude than that detectable at the cornea.
In Vivo Measurements On Human Lens Using Quasi-Elastic Light Scattering
Authors: Magnante Peter C. , Benedek George B. , Libondi Teodosio , Chylack Leo T.
Published: February 2023

Quasi-elastic light scattering is a useful method to determine the size distribution of sub-micron particles in fluids. We have applied this technique to measure in vivo changes in the association of human lens protein constituents that occur with aging and cataractogenesis. The autocorrelation function of the scattered light has been analyzed by a two component exponential where each component is characterized by an intensity and decay rate. Each pair of parameters is associated with one of two major protein groups in the lens. These parameters have been determined as a function of age and position within normal, clear lenses.
The Use of Cross-Polarizing Filters for Threshold Central Visual Field Testing
Authors: Sadun Alfredo A. , Wall Michael , Borchert Mark , Johnson Betty
Published: February 2023

Amsler grid testing is commonly used for evaluating the central ten degrees of visual field (1). This test is particularly important for monitoring patients with senile macular degeneration for the earliest possible sign of neovascular growth. Patients viewing this grid may report abnormalities representing metamorphopsia, scotomas, and depressions of the central field.
Normal Variation in the Stiles-Crawford Function Peak Location
Authors: Applegate Raymond A. , Meade Diana L. , Sorenson Christina M.
Published: February 2023

Properties of human photoreceptor alignment can be studied noninvasively by measuring the Stiles-Crawford effect (SCE), a psychophysical determination of the relative efficiency of light in eliciting a visual response as a function of pupil entry. Typical data are graphically displayed in Figure 1 as filled circles.
Visually Evoked Potentials to motion onset-offset: an alternative tool for clinical electrophysiology?
Authors: Dagnelie Gislin , Maier John
Published: February 2023

Visually Evoked Potentials can provide valuable information concerning pathology at various stages along the visual pathway, and have thus gained acceptance as diagnostic tools in ophthalmology and neurology. Unfortunately, their applicability has sometimes been questioned due to inconsistencies in results reported by various laboratories. Standardization of stimuli and of recording procedures have been instrumental in the reduction of such inconsistencies, but relatively large interindividual variations, even in normal observers, still occurs and remains a limiting factor for the diagnostic value of VEPs.
The Effect of Penetrating Keratoplasty on Contrast Sensitivity
Authors: Mannis Mark J. , Zadnik Karla , Johnson Chris , Adams Craig
Published: February 2023

Increasing numbers of corneal transplants for visual rehabilitation are being performed throughout the world. The adequacy of visual function in these patients has been assessed only in terms of visual acuity measurement, yet non-acuity parameters such as contrast sensitivity may be important indices of the adequacy of visual performance in these patients for a variety of real-world conditions. Contrast sensitivity may therefore provide a more sensitive clinical indicator of visual function of these patients within the limits of visual resolution.
Functional Perimetry and Visual Space
Authors: Arditi Aries , Faye Eleanor E.
Published: February 2023

Perimetry is a useful tool for monitoring the health and integrity of the retina and associated higher visual processes but as commonly used, is a rather poor predictor of visual function. Only a few efforts have been made at rectifying this shortcoming (Esterman, 1967, 1968, 1982). As we reported at ARVO this spring (Arditi and Faye, 1986), defining the functional field requires consideration of both the spatial consequences of having two monocular field maps with different but overlapping views of space and the demands on that binocular field of specific visual tasks. This paper discusses the geometric analysis of the normal and impaired visual fields and the consequences of retinal field defect location on space perception. We also present a method for functional analysis of visual fields using an automated perimeter and a microcomputer.
Clinical Use of the 100-Hue Test: Learning Artifact
Authors: Breton Michael E. , Fletcher Dorothy E. , Krupin Theodore
Published: February 2023

The Farnsworth-Munsell 100-Hue color test has been used extensively in studying the effects of many types of ocular pathology on the performance of the color mediating mechanisms. Many recent reports show that color discrimination performance as measured by the 100-Hue test is affected early in primary open angle glaucoma (POAG) as well as other optic nerve and retinal disorders. These studies typically demonstrate statistical significance of the effect of the disease process on color vision for pooled data from well defined patient and normal control groups. However, clinical usefulness of color test procedures depends upon the successful application on a prognostic basis of the group results to individual patients at risk. In this context we have identified a learning artifact associated with current routine use of the 100-Hue test which complicates the interpretation of repeat tests in following disease progression and which interferes with test protocols that require repetitive testing at one or more sessions such as occurs with the measurement of intensity-response functions.
Reading Performance with Peripheral Viewing Using Rapid Serial Visual Presentation
Authors: Turano Kathleen , Rubin Gary S.
Published: February 2023

People with central field loss (CFL) exhibit a substantial deficit in reading performance. Legge et al.1 have shown that the median reading rate of people with CFL was 25 words per minute when the character size was optimal. The median reading rate of low-vision observers with intact central fields was 130 words per minute. The cause of the decreased reading rate in people with CFL is not known. One hypothesis is that pattern analysis performance is limited in peripheral vision2 and therefore is not capable of mediating rapid reading. Even when the character size is scaled according to the cortical magnification factor, reading rates may not reach the same magnitude as found with foveal viewing.
Adaptation Dependent Sensitivity Losses: Implications for cone receptor involvement in RP
Authors: Greenstein Vivienne C. , Hood Donald C. , Siegel Irwin M. , Carr Ronald E.
Published: February 2023

The assessment of a sensitivity loss in patients with retinal disease is often performed in the presence of a background. Marré and Marré1, for example, have devised a technique based on Wald's version of Stiles' two-color threshold technique to measure the relative loss in three "basic cone mechanisms", each mechanism is isolated with a single chromatic background. Other investigators have argued for a selective sensitivity loss of a blue cone mechanism or a chromatic mechanism based upon data also collected at one or two adapting field intensities. The implicit assumption is that sensitivity loss of a particular cone mechanism is independent of the level of adaptation. This paper has two goals. First, we review evidence indicating that sensitivity loss is not independent of the level of adaptation in patients with RP, and we propose that models of sensitivity loss must incorporate a model of adaptation2. Second, we apply the model of adaptation proposed by Hood and Greenstein3 to assess whether the tvi data from RP patients support the hypothesis that RP primarily affects the receptors.
Clinical Assessment of Short-Wavelength-Sensitive Cone Acuity
Authors: Swanson William H.
Published: February 2023

Several studies have evaluated contrast sensitivity of the short-wavelength-sensitive (SWS) cones using chromatic adaptation to produce low contrasts for the middle-wavelength-sensitive (MWS) and long- wavelength-sensitive (LWS) cones, and large contrasts for the SWS cones.1-3 With sufficiently low MWS and LWS cone contrasts, spatial patterns can only be detected by the SWS cone pathway. These studies have indicated that the SWS cone pathway has poor spatial resolution, a finding which is consistent with histological data on SWS cone density in the primate retina4. Wilson, Blake and Pokorny3 recently presented a method for measuring acuity of the SWS cone pathway using black and white square-wave gratings produced on a Macintosh™ computer screen, passed through a blue filter, and optically superimposed on a uniform yellow field. They measured acuity as a function of intensity of the yellow field, and found that acuity decreased as luminance increased from 0 log td to 3.04 log td, then remained constant. Their interpretation of this finding was that for yellow field luminances above 3 log td, acuity is mediated by the SWS cone system. The purpose of the present study is to develop a short version of this method, to determine the variability of SWS cone acuity in normals, and to evaluate the usefulness of the method for detecting SWS cone loss in patients with retinitis pigmentosa and good Snellen acuity.
Pattern-ERG to alternating checks in cats: evidence of retinal spatial frequency tuning, and effect of optic nerve section.
Authors: Tobimatsu S. , Celesia G. G. , Cone S.
Published: February 2023

Pattern-ERG (P-ERG) is evoked by pattern-reversal stimuli, where the pattern alternates, while the mean luminance is kept constant. P-ERG evaluates primarily the function of the retina serving the central visual field and mostly the macular region (2,5,7,9,11-13,17). In 1981 Maffei and Fiorentini studied P-ERG in cats and demonstrated that the P-ERG disappeared after section of the optic nerve. They correlated the abolition of the P-ERG with retrograde degeneration of the ganglion cells. These and other studies (7,12-13) suggest that the P-ERG originates in ganglion cells. On the other hand, detailed physiological study of P-ERG in humans showed that P-ERG contains local luminance components and therefore may represent pre-ganglionic activity (1,11,15,17-18).
Laser Photocoagulation Dosimetry using Two Wavelength Fundus Reflectometry
Authors: Pflibsen Kent P. , Delori François C. , Pomerantzeff Oleg
Published: February 2023

The use of lasers in photocoagulating disease pathologies in the eye continues to expand as ever more ocular disorders yield to this treatment modality. While non-invasive surgery by lasers has proven advantageous there remains significant room for improving the efficacy of lasers in ocular photosurgery.
Measuring Visual Function in Infants and Young Children with Visual Impairment
Authors: Katsumi Osamu , Hirose Tatsuo , Mehta Mehul C.
Published: February 2023

For evaluating vision in infants and young children, optokinetic nystagmus (OKN), preferential looking (PL), and pattern reversal visual evoked response (PVER) are now available. Each method has its own advantages and disadvantages, as has been extensively reported elsewhere (1), and their use has resulted in a much clearer understanding of the overall pattern of visual development during childhood.
Evaluating the Photoreceptor/RPE Complex with an SLO
Authors: Eisner Ann E. , Burns Stephen A. , Hughes George W. , Webb Robert H.
Published: February 2023

New technology has allowed us to realize the potential of imaging reflectometry in the fundus, as well as better understand the optical factors contributing to measurements. We are mapping photopigment density of human retinas to investigate photoreceptor/retinal epithelial function. We compare maps obtained from reflectometry with results from psychophysical techniques that measure photopigment optical density and visual function. These comparisons can be made across retinal eccentricity and retinal illuminance in the same observer.
Cortical Potentials Evoked by Short Wavelength Patterned Light
Authors: Rabin Jeff , Adams Anthony J. , Switkes Gene , Schneck Marilyn , Huie Ken
Published: February 2023

The S cone visual pathway is characterized by poor spatial and temporal resolution, and relatively low sensitivity to light.1,3 In addition, S-pathway sensitivity loss occurs in a number of ocular diseases.4 While psychophysical techniques are typically used to specify this loss, direct measures of S-pathway integrity are lacking. Pattern-evoked cortical potentials (PECPs) may provide a sensitive, objective index of S-pathway function.5,6 This report describes spectral, spatial and temporal properties of the S-pathway PECP. Applications of this approach are considered.
Age-Related Differences in Early Dark Adaptation1
Authors: Sturr Joseph F. , Taub Harvey A. , Hall Benjamin A.
Published: February 2023

The rapid mechanisms of sensitivity regulation following light offset are distinct from the more commonly studied slower form of dark adaptation and are called early dark adaptation (EDA) (Baker, 1953, 1963; Rinalducci, 1967; Geisler, 1983). It is well established that EDA is determined by peripheral retinal mechanisms (Baker, 1973; Baker and Donovan, 1982; Geisler, 1983; Hayhoe, Benimoff, and Hood, 1987). Previous experiments from our laboratory have demonstrated significant alterations in early light adaptation as a function of age (Sturr, Kelly, Kobus and Taub, 1982; Sturr, Church, and Taub, 1985). However, EDA has not yet been investigated in the aging visual system. These early mechanisms of sensitivity regulation may be especially sensitive to age-related changes in vision which would not be revealed by more traditional measures of visual function such as visual acuity. Therefore, the current study evaluated EDA for both young and old observers.
Do The Spatial Abnormalities of Strabismic Amblyopic Eyes Explain their Reduced Acuity for Letters?
Authors: Flom Merton C. , Jiang Bai-Chuan , Bedell Harold E. , Simpson Trefford
Published: February 2023

Amblyopia, an anomaly of human vision defined as substandard visual acuity even though any refractive error has been optically neutralized and there is no ocular disease, develops mainly in children who have significant interocular difference in refractive error (anisometropia) or a manifest oculomotor deviation (strabismus). So much attention has been given to acuity issues in amblyopia, such as the acuity cutoff for diagnosis, appropriate acuity optotypes, and how much of the acuity chart to exposed, that it is common to think that acuity is the main, only, or even the fundamental defect in amblyopia.
Visual Information Sampling Efficiency in Low Vision Observers
Authors: Schuchard Ronald A.
Published: February 2023

Visual information sampling efficiency is defined as the average fraction of the total visual information utilized by the observer to perform signal detection tasks and is found by measuring the performance of signal detection as a function of added visual noise (signal-to-noise ratio). A sampling efficiency of 100% has been demonstrated for normally-sighted observers, that is, they sampled all available visual information in the image.1 Full efficiency was found over a variety of parameters; field of view, random versus regular dots distributions, varying luminance, and blurred dots. Low vision observers with either central or peripheral visual field loss would be suspected of reduced sampling efficiency. The visual field loss would force the observers to use a smaller region of visual field to sample the visual information. To the extent that an individual with visual field loss acquires less visual information in a single fixation (compared to the person with full visual fields), one would expect that more fixations are necessary to acquire all relevant information. As the number of required fixations increase, there would be a corresponding increase in the amount of information that must be committed to memory. These considerations led to the present study of whether observers with impaired information acquisition due to visual field loss are less efficient in sampling visual information than normally sighted people.
The Use of Functional Vision Assessment in Predicting Mobility Problems in Older Adults
Authors: Ball Karlene K. , Roenker Daniel L. , Bruni John R.
Published: February 2023

Ophthalmolgists and optometrists are sometimes called upon to evaluate the functional status of the visual system in terms of what activities an individual may engage in, in addition to diagnosing the presence of pathology. This may prove a difficult task since there is often a mismatch between sensory loss and the ability to function in the world (i.e. some individuals with dramatic losses seem to function quite well while others, with only minor sensory loss, report great difficulty in visually guided activities). This difficulty may be exacerbated in the older population, where there is a marked increase in the range of functional abilities, and often no clear distinction between aging and early onset of disease.
ERG b-Wave Implicit Time and b/a Wave Ratio as a Function of Intensity in Central Retinal Vein Occlusion
Authors: Breton Michael E. , Schueller Albert , Montzka Dan
Published: February 2023

The effectiveness of the electroretinogram (ERG) as an indicator of the eventual development of neovascular complication in central retinal vein occlusion (CRVO) has been supported by several recent studies. Breton et al (1989) and Johnson et al (1988) report significant predictive power for the intensity-response curve fitting parameters Log K and Rmax, as well as for the b/a wave amplitude ratio and 30 Hz implicit time. Kaye and Harding (1988) found single flash b-wave implicit time to be the most predictive parameter of subsequent neovascular complication, but also found significant predictive power for b/a wave amplitude ratio and b-wave amplitude. Kaye and Harding further report that the predictive power of b-wave implicit time did not change with intensity at six stimulus intensity levels. Johnson et al also report that b-wave implicit time is an effective predictor of neovascular complication. The other two reports differ from that of Breton et al which did not find b-wave implicit time to have predictive power and deleted it from their analysis.
Kinetic Perimetry for Pediatric Populations: Humphrey and Goldmann Perimetry
Authors: Mayer D. Luisa , Brar Manu , Goldberg Melissa , Palafox German
Published: February 2023

The introduction of automated perimeters has enabled quantitative and standardized testing of the visual fields of patients. But the static perimetry employed in these instruments is too lengthy for young children. Kinetic perimetry is more successful: kinetic fields have been reported in children as young as 2 1/2 years using the Goldmann perimeter (1) and in infants using other kinetic methods (eg 2, 3). Recently, a modification became available for the Humphrey Visual Field Analyzer (Allergan-Humphrey) that enables kinetic perimetry. Potential advantages of the Humphrey kinetic program for pediatric populations are similar to those for adult patients, including minimal examiner skills, standardized kinetic scan parameters, and the possibility of combining kinetic and static testing.
A Method for Assessing Stereopsis and Positional Sensitivity in Normally-Sighted and Low Vision Observers
Authors: Raasch Thomas W.
Published: February 2023

Normal human observers have been shown to be acutely sensitive to the relative spatial position of visual features. The angular extent of just noticeable differences in position are much smaller than spatial resolution thresholds, and these very fine thresholds are called the hyperacuities (Westheimer, 1975). Examples of visual tasks that yield hyperacute thresholds are vernier alignment, bisection, stereoscopic depth, and relative motion detection.
The Pupil Grating Response and Visual Acuity
Authors: Cocker Kenneth D. , Moseley Merrick J.
Published: February 2023

The pupil responds to a wide range of physical, physiological and psychological stimuli. Changes in retinal illuminance provide the most immediate and perhaps best understood of the inputs to the pupillomotor system, however many elements of a visual stimulus can trigger a pupillary response. Recent studies using dynamic pupillometry have revealed a response to pattern stimulation which varies systematically with spatial frequency1-4. Several mechanisms underlying the pattern response have been proposed including changes in local luminance2,3 and accommodation3. Keenleyside5 found no evidence that either of these factors played any significant role in the generation of pupillary responses to sine-wave gratings. In 1985 Barbur and Forsyth6 suggested a central origin for the pupil grating response (PGR) and presented data from an individual with an accidentally severed left optic radiation in whom responses to both light and pattern were obtained in the subject's normal hemifield - however, within the blind hemifield, no response to pattern could be elicited despite the presence of a near normal light response.
New Views of the Retina/ RPE Complex: Quantifying Sub-retinal Pathology
Authors: Elsner Ann E. , Burns Stephen A. , Kreitz Mark R. , Weiter John J.
Published: February 2023

The early stages of sub-retinal pathology are often difficult to observe and quantify in vivo. One important example is age-related macular degeneration (AMD), which is one of the chief causes of visual loss in the United States. Histopathological studies of human eyes indicate that there is a deposition of material in the layers beneath the retina, particularly in Bruch’s membrane prior to clinical detection of the disease. (Fig 1, as in Ref 1). These changes are not visible clinically when the deposits are diffuse or small (e.g. <25 urn). We are currently attempting to determine if these earliest changes can be detected by non-invasive techniques.
Can Short Wavelength Sensitivity Losses Predict the Development of Glaucomatous Visual Field Defects?
Authors: Johnson Chris A. , Adams Anthony J. , Casson Evanne J. , Nelson-Quigg Jacqueline M.
Published: February 2023

Recently, several laboratories have introduced chromatic adaptation techniques to automated perimetry in an effort to isolate the activity of short-wavelength-sensitive (SWS) mechanisms. 1-6 In particular, short-wavelength sensitivity losses in the visual field have been reported to be more prevalent than deficits obtained with standard perimetry in ocular hypertensives and patients with early glaucomatous damage. 1-4 In addition, we have found that short wavelength sensitivity losses appear to have both diffuse and localized components, 1,3 that short wavelength sensitivity defects are generally larger in area than those found with standard automated perimetry,3 that there is partial but not complete overlap between short wavelength sensitivity losses and visual field defects with standard perimetry,3 and that short wavelength sensitivity losses in ocular hypertension and glaucoma display nerve fiber bundle patterns. 4 These results indicate that short wavelength sensitivity losses may be an early indicator of glaucomatous damage.
Photorefractive Evaluation of Infant Accommodation and Convergence
Authors: Riddell P. M. , Grose-Fifer J. , Hainline L. , Abramov I.
Published: February 2023

The need for early vision screening is widely acknowledged in the prevention of amblyopia. Paraxial photorefraction can be easily and rapidly used to assess accommodation and convergence in young infants. We have tested 818 infants aged between 15 days and 36 months, using paraxial photorefraction. The procedure was first described by Kaakinen (1979) and analyzed by Howland (1980; 1985) and Bobier and Braddick (1985). Our technique has the major advantage of being quick and totally non-invasive.
Monochromatic Wavefront Aberrations in Myopia
Authors: Applegate Raymond A.
Published: February 2023

While several investigators have quantified the eye's higher order aberrations using a variety of techniques, to our knowledge little or no work has been published on the influence of the magnitude of refractive error on the eye's higher order aberrations. In this paper we present evidence which suggests that the eye's monochromatic wavefront aberrations tend to increase as a function of increasing myopia.
Contrast Discrimination in Observers with Vision Loss
Authors: Schuchard Ronald A.
Published: February 2023

Many people with vision loss have difficulty identifying objects encountered in common daily experiences. The measurement of contrast thresholds over a range of spatial frequencies (contrast sensitivity function) has been investigated in low vision observers to explain these difficulties and to recommend techniques for better identification by compensating for reduced contrast sensitivity. However, objects encountered in common daily experiences are rarely viewed in low contrast environments. Although contrast discrimination functions have been shown to be similar in shape and superimposed when normalized by the contrast thresholds in normally sighted observers (e.g., Legge and Kersten, 1987), very little is known about the contrast discrimination function for observers with low vision. That is, while the entire contrast discrimination function can be specified by the contrast sensitivity function for a stimulus in normally sighted observers, it is not known whether this relationship is also true for observers with vision loss. Leat and Millodot (1990) report that contrast discrimination and contrast sensitivity are independent in observers with vision loss. Therefore, it is possible that identification of suprathreshold objects has no relationship to the contrast sensitivity function in observers with vision loss (e.g., Rubin and Schuchard, 1990). The characteristics of contrast discrimination functions in observers with vision loss were studied as they related to the contrast sensitivity functions.
Physiological statokinetic dissociation by automated perimetry
Authors: Hudson C. , Wild J. M. , Hussey M. K.
Published: February 2023

The term statokinetic dissociation (SKD) is used in clinical perimetry. It describes a greater sensitivity to a kinetic stimulus relative to an identical static stimulus. SKD was reported initially in patients with occipital lobe lesions1, and subsequently in patients with various other forms of neurological and ocular disease2-9.
Quantification of monocular motion asymmetries with counterphase gratings and motion nulling techniques
Authors: Teller Davida Y. , Succopl Annemarie , Hartmann E. Eugenie
Published: February 2023

Some adult patients with a history of strabismus, amblyopia, and/or related problems, when tested monocularly, show an asymmetry of optokinetic nystagmus (OKN). The asymmetry is such that patterns moving temporal-to-nasal (T-N) elicit OKN more readily than do nasal-to-temporal (N-T) patterns (Mohn, Sireteanu, and van Hof-van Duin, 1986). Similarly, some such patients exhibit asymmetries of smooth pursuit eye movements and perceived velocity (Tychsen and Lisberger, 1986).
The Classification of Amblyopia on the Basis of Visual and Oculomotor Performance
Authors: McKee Suzanne P. , Schor Clifton M. , Steinman Scott B. , Wilson Nance , Koch Gary G. , Davis Sonia K. , Hsu-Winges Charlene , Day Susan H. , Chan Christine L. , Movshon J. Anthony , Flom Merton C. , Lev Dennis M. , Flynn John T.
Published: February 2023

Amblyopia is most simply defined as a loss of visual acuity without an identified organic cause. Traditionally, the amblyope is roughly classified as strabismic, anisometropic, refractive or deprivational, according to the accompanying condition thought to be responsible for the acuity loss. Although it is widely recognized that these classes are neither particularly uniform nor discriminative, there is no established means of classifying amblyopes on the basis of visual function alone. Our primary objective is to create a classification system for amblyopia, based on a broad spectrum of clinical, psychophysical and oculomotor abnormalities -- a system that could supplement or supplant the traditional approach leading to better diagnosis and treatment. We here report the results from a pilot study showing that this objective is feasible. Two hundred and fifteen naive subjects, including eighty-two amblyopes, seventy-three recovered amblyopes, forty non-amblyopic strabismic or anisometropic ("at risk") subjects, and twenty normal subjects, participated in the study. The results from numerous psychophysical and oculomotor tests were analyzed statistically to determine if clusters of subjects with similar visual and oculomotor capabilities would emerge from the data base. Cluster analysis identified nine separate clusters. The laboratory measurements were sufficient to predict cluster membership and accounted for between-cluster variation, including whatever variation was due to Snellen acuity and clinical diagnosis.
Polaroid Photoscreening for Amblyogenic Factors in a Normal Population
Authors: Preston Karen L. , Morris Caroline , Morris Robert , Scott William , Cook-Buchenau Jo , Dungy Claibourne I.
Published: February 2023

Amblyopia is a leading cause of vision loss.1,2 Since early identification and treatment of amblyopia may lead to more favorable acuity outcomes, considerable attention has been paid to the development of amblyopia screening techniques.3,4 The direct measurement of visual acuity in very young and preverbal children can be time consuming in the context of mass screenings5-8, expensive9, and may tend to underestimate the incidence and magnitude of amblyopia.6 Therefore, most screening methodologies are based on the identification of amblyogenic factors (i.e., strabismus, refractive errors and media opacities).
Psychophysical Census of Foveal Cones in Macular Degeneration.
Authors: Geller Andrew M. , Sieving Paul A.
Published: February 2023

We have developed a method and models to quantify photoreceptor loss and physiological change in patients with macular degeneration. We initially considered a metric based on the correlation between acuity and photoreceptor sampling rate in foveal and near parafoveal vision of normal observers1. Ultimately, however, when comparing results of a task with simulated photoreceptor loss2 to those of a conventional acuity vs. eccentricity task3, we realized this metric was untenable. In the case of eccentric viewing, the sampling rate of the receptor array decreases together with mean photoreceptor density and visual acuity. In the case of receptor loss, however, the sampling rate is set by the original near-neighbor relationship of the sampling elements and loss merely introduces broad-band spatial noise. Sampling rate no longer corresponds with mean density. Thus a patient may maintain good visual acuity because his modal foveal sampling rate remains at the original sampling rate, yet because of this, an acuity task is inadequate to quantify photoreceptor loss.
Predicting Exudative Age-Related Maculopathy
Authors: Mayer Melanie J. , Ward Brian , Klein Ronald , Talcott Joel B. , Dougherty Robert F.
Published: February 2023

Exudative age-related maculopathy (ARM) is the leading cause of vision loss in the United States among the elderly.1,2 The goal of our research is to identify those most at risk for exudative ARM before the development of exudative and neovascular complications and before severe loss of acuity. Those identified as "Most At Risk" could monitor their vision carefully for visual distortion or loss or for further flicker sensitivity loss, allowing early clinical evaluation and possible treatment should exudative symptoms appear. Predictors of exudative ARM could also provide information about the progress and rate of development of pre-exudative stages of ARM and could help to evaluate proposed treatments for the earlier stages of ARM.
Chronic Effects of Intraocular Pressure in Normals as a Function of Retinal Location.
Authors: Tyler Christopher W. , Stamper Robert L. , Hawker Nina
Published: February 2023

Sensitivity to sinusoidal temporal modulation (flicker sensitivity) for a uniform stimulus field is proving to be a valuable tool for in ophthalmological diagnosis. Flicker sensitivity has been shown in a variety of diseases to provide earlier detection than previous available tests;1,2 to measure a reversible component of the visual susceptibility to disease;3 provide differential diagnosis among conditions which are similar according to other tests;4 to characterize the nature of the sensory deficit; 4,5 and to provide information as to which retinal mechanisms are affected by the disease.4-6
Visual Function Following Phototherapeutic Excimer Laser Keratectomy (PTK)
Authors: Adamsons Ingrid , Rubin Gary S. , Stark Walter J.
Published: February 2023

Excimer laser keratectomy ablates superficial corneal tissue and recontours the corneal surface with great precision. It is being evaluated for correction of myopia (photorefractive keratectomy, PRK), and for correction of astigmatism and removal of superficial corneal opacities (phototherapeutic keratectomy, PTK). Ongoing clinical trials for PRK report that laser treatment for simple myopia in otherwise normal eyes reduces refractive error and improves uncorrected visual acuity. However PRK has also been reported to increase glare disability.1,2 Its effect on contrast sensitivity is unclear.3,4 One study5 showed that PTK improved visual acuity in 21 of 27 eyes with corneal scarring. But contrast sensitivity and glare disability were not measured. The goal of this ongoing study is to evaluate the post-operative change in objective and subjective visual function in patients enrolled in a PTK clinical trial.