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Background/AimThis study aimed to compare central visual sensitivity under monocular and binocular conditions in patients with glaucoma using the new imo static perimetry.MethodsFifty-one consecutive eyes of 51 patients with open-angle glaucoma who were affected with at least one significant point in the central 10° were examined in this cross-sectional study. Monocular and binocular random single-eye tests were performed using the imo perimeter and the Humphrey field analyser (HFA) 24-2 and 10-2 tests. The eyes were assigned to ‘better’ and ‘worse’ categories based on the visual acuity and central visual thresholding. Central visual sensitivity results obtained by monocular, binocular random single-eye tests and binocular simultaneous both eye test were compared.ResultsThe average mean deviation with the HFA 24-2 was −5.5 (–1.5, –14.6) dB (median, (IQR)) in the better eyes and −18.0 (–12.9, –23.8) dB in the worse eyes. The mean sensitivity in the central 4 points of the visual field (VF) of the worse eyes was lower when measured under the binocular eye condition than under the monocular condition. Conversely, this value of the better eyes was greater when measured under the binocular eye condition than under the monocular condition.ConclusionsThe central sensitivity of the better eyes was better and that of the worse eyes poorer with binocular testing than with monocular testing in patients with glaucoma. Although monocular VF testing is still the most straightforward means to monocularly monitor glaucoma at clinical settings, binocular testing, such as provided with imo perimetry, may be a useful clinical tool to predict the effect of VF impairments on a patient’s quality of visual life.

Purpose: The present study aimed to assess the ability of en face slab images of maculae to detect residual nerve fiber bundles in eyes with advanced glaucoma. Methods: This study included 36 eyes with diffuse thinning of the ganglion cell and inner plexiform layers (GCL+IPL). Inclusion criterion was GCL+IPL thickness of

Objective: Microperimetry (MP) is used to assess visual sensitivity mediated by the central retina. As such, MP performance is a candidate outcome measure for gene therapy trials. Herein, we review MP results in three inherited retinal disorders for which gene therapy trials have been initiated-choroideremia, Stargardt disease, and X-linked juvenile retinoschisis. Each of these disorders typically presents in childhood and each has distinct effects on the central retina. Outcomes and Results: Our review indicates that microperimetry is feasible in each of these conditions. The MP sensitivity maps vary among conditions consistent with known effects of each of the three conditions. There is, however, within each of the three disorders considerable variability in fixation stability and in the pattern of sensitivity loss. Conclusions: Microperimetry is a valuable tool for monitoring functional aspects of central retina in an individual patient, especially in combination with other modalities such as OCT, autofluorescence, and acuity and thus may contribute to evaluating the efficacy of gene treatments. Variability of the MP parameters raises some cautions in application of MP as an outcome measure in treatment trials that may have small sample sizes. Nonetheless, we suspect that MP will continue to have a rightful place in future gene therapy trials.

PURPOSE To determine whether there are significant correlations between the focal photopic negative response (PhNR), the focal visual sensitivity and the ganglion cell complex (GCC) thickness in glaucomatous eyes. STUDY DESIGN Single-center observational study. METHODS Fifty-two eyes of 52 patients (71.4 ± 9.42 years) with clinically diagnosed open angle glaucoma were studied. Thirty-six age-matched normal subjects served as controls. The focal PhNR of the focal macular electroretinograms (fmERGs) were elicited by a 15° circular, a superior semicircular or an inferior semicircular stimulus centered on the fovea. The thickness of the GCC was measured in the corresponding retinal areas in the spectral-domain optical coherence tomographic images. The visual sensitivities (dB) were measured by microperimetry at the retinal area where the fmERGs were elicited and were converted to liner values (1/Lambert). RESULTS The focal PhNR amplitudes were significantly correlated with the visual sensitivities of the full-circle (R = 0.532), the superior (R = 0.530) and inferior (R = 0.526) semicircular responses (P

People can perceive 3D information from contour drawings and some types of configurations of contours in such drawings are important for 3D perception. We know that our visual system is sensitive to these configurations. Koshmanova & Sawada (2019, Vision Research, 154, 97–104) showed that the sensitivity is higher to a parallel configuration of contours than to a perpendicular configuration of contours. In this study, two psychophysical experiments were conducted that compared the sensitivity to a parallel configuration to two different configurations. In Experiment 1, orientation thresholds were measured with parallel and converging configurations composed of three contours. In Experiment 2, orientation thresholds of configurations composed of two contours were measured with parallel, collinear, and perpendicular configurations. The results of Experiment 1 showed that the visual system is more sensitive to parallel configurations than to converging configurations. The results of Experiment 2 showed that the sensitivity to the parallel configuration is analogous to the sensitivity to the collinear configuration, and it is higher than the sensitivity to the perpendicular configuration. The role that the parallel configuration plays in the 3D perception of contour-drawings is discussed.

The two- and one-photon visual sensitivities (2phS and 1phS) of cataract patients were tested before and after IOL surgery. Mean change in 2phS was twice smaller than 1phS indicating that 2phS is less affected by cataract.

Purpose Many people experience unilateral degraded vision, usually owing to a developmental or age-related disorder. There are unresolved questions regarding the extent to which such unilateral visual deficits impact on sensorimotor performance; an important issue as sensorimotor limitations can constrain quality of life by restricting ‘activities of daily living’. Examination of the relationship between visual deficit and sensorimotor performance is essential for determining the functional implications of ophthalmic conditions. This study attempts to explore the effect of unilaterally degraded vision on sensorimotor performance. Methods In Experiment 1 we simulated visual deficits in 30 participants using unilateral and bilateral Bangerter filters to explore whether motor performance was affected in water pouring, peg placing, and aiming tasks. Experiment 2 (n = 74) tested the hypothesis that kinematic measures are associated with visuomotor deficits by measuring the impact of small visual sensitivity decrements created by monocular viewing on sensorimotor interactions with targets presented on a planar surface in aiming, tracking and steering tasks. Results In Experiment 1, the filters caused decreased task performance—confirming that unilateral (and bilateral) visual loss has functional implications. In Experiment 2, kinematic measures were affected by monocular viewing in two of three tasks requiring rapid online visual feedback (aiming and steering). Conclusions Unilateral visual loss has a measurable impact on sensorimotor performance. The benefits of binocular vision may be particularly important for some groups (e.g. older adults) where an inability to complete sensorimotor tasks may necessitate assisted living. There is an urgent need to develop rigorous kinematic approaches to the quantification of the functional impact of unilaterally degraded vision and of the benefits associated with treatments for unilateral ophthalmic conditions to enable informed decisions around treatment.

PurposeThe accuracy of conventional visual function tests, which emit visible light, decreases in patients with corneal scars, cataracts, and vitreous hemorrhages. In contrast, infrared (IR) light exhibits greater tissue penetrance than visible light and is less susceptible to optical opacities. We therefore compared conventional visual function tests against infrared 2-phton microperimetry (2PM-IR) in a subject with a brunescent nuclear sclerotic and posterior subcapsular cataract before and after cataract surgery.MethodsTesting using infrared light microperimetry from a novel device (2PM-IR), visible light microperimetry from a novel device (2PM-Vis), conventional microperimetry, and the cone contrast threshold (CCT) test were performed before and after cataract surgery.ResultsRetinal sensitivity assessed using 2PM-IR, 2PM-Vis, and cMP improved by 3.4dB, 17.4dB, and 18dB, respectively. Cone contrast threshold testing improved for the S-cone, M-cone, and l-cone by 111, 14, and 30.Conclusions and importance2PM-IR, unlike conventional visual function tests, showed minimal variability in retinal sensitivity before and after surgery. Thus, IR visual stimulation may provide a more accurate means of measuring neurosensory retinal function by circumventing optical media opacities, aiding in the diagnosis of early macular disease.

Saccadic eye movements are typically preceded by selective shifts of visual attention. Recent evidence, however, suggests that oculomotor selection can occur in the absence of attentional selection when saccades erroneously land in between nearby competing objects (saccade averaging). This study combined a saccade task with a visual discrimination task to investigate saccade target selection during episodes of competition between a saccade target and a nearby distractor. We manipulated the spatial predictability of target and distractor locations and asked participants to execute saccades upon variably delayed go-signals. This allowed us to systematically investigate the capacity to exert top-down eye movement control (as reflected in saccade endpoints) based on the spatiotemporal dynamics of visual attention during movement preparation (measured as visual sensitivity). Our data demonstrate that the predictability of target and distractor locations, despite not affecting the deployment of visual attention prior to movement preparation, largely improved the accuracy of short-latency saccades. Under spatial uncertainty, a short go-signal delay likewise enhanced saccade accuracy substantially, which was associated with a more selective deployment of attentional resources to the saccade target. Moreover, we observed a systematic relationship between the deployment of visual attention and saccade accuracy, with visual discrimination performance being significantly enhanced at the saccade target relative to the distractor only before the execution of saccades accurately landing at the saccade target. Our results provide novel insights linking top-down eye movement control to the operation of selective visual attention during movement preparation.

Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments.

Purpose:The purpose of this article was to evaluate the relationship between macular optical microangiography (OMAG), ganglion cell-inner plexiform layer (GCIPL) thickness, and visual sensitivity measurements of different macular sectors in primary open-angle glaucoma.Methods:In a cross-sectional study, 39 eyes of 26 primary open-angle glaucoma patients underwent optical coherence tomography imaging and 10-2 visual field examination of the macula in the same session. Linear regression models were used to evaluate the relationships between OMAG, GCIPL thickness, and visual sensitivity measurements in different macular sectors. Strength of relationship was reported as coefficient of determination (R-2).Results:R-2 values for the associations between OMAG and GCIPL thickness measurements ranged from 0.37 in the temporal sector to 0.56 in the inferior macular sector. R-2 values for the association between OMAG and visual sensitivity measurements ranged from 0.23 in the superior to 0.53 in the inferior macular sector. R-2 values for the association between GCIPL thickness and visual sensitivity measurements ranged from 0.15 in the superior to 0.62 in the temporal sector.Conclusions:The strongest associations between OMAG, GCIPL thickness, and visual sensitivity measurements were found in the inferior macular sector. The association of OMAG with GCIPL thickness measurements was as strong as the association between OMAG and visual sensitivity measurements in the inferior macular sector.

Visual features such as edges and corners are carried by high-order statistics. Previous analysis of discrimination of isodipole textures, which isolate specific high-order statistics, demonstrates visual sensitivity to these statistics but stops short of analyzing the underlying computations. Here we use a new texture centroid paradigm to probe these computations. We focus on two canonical isodipole textures, the even and odd textures: any 2 × 2 block of even (odd) texture contains an even (odd) number of black (and white) checks. Each stimulus comprised a spatially random array of black-and-white texture-disks (background = mean gray) that varied in their fourth-order statistics. In the Even (Odd) condition, disks varied along the continuum between random coinflip texture and pure (highly structured) even (odd) target texture. The task was to mouse-click the centroid of the disk array, weighting each disk location by the target structure level of the disk-texture (ranging from 0 for coinflip to 1 for even or odd). For each of block-sizes S = 2 × 2 , 2 × 3, 2 × 4 and 3 × 3, a linear model was used to estimate the weight exerted on the subject’s responses by the differently patterned blocks of size S. Only the results with 2 × 4 and 3 × 3 blocks were consistent with the data. In the Even condition, homogeneous blocks exerted the most weight; in the odd condition, block-pattern symmetry was important. These findings show that visual mechanisms sensitive to four-point correlations do not compute evenness or oddness per se, but rather are activated selectively by features whose frequency varies across isodipole textures.

Purpose To investigate the relationship between intereye visual field defect (VFD) asymmetry and subsequent VF progression in primary open-angle glaucoma (POAG). Methods Moderate-stage patients with POAG (226 eyes of 113 patients) with a single hemifield defect were followed for 8.7 years. Participants were categorized into three groups by initial VF pattern: (1) unilateral VFD, (2) bilateral VFD within same hemifield (superior–superior, inferior–inferior), (3) bilateral VFD within opposite hemifield (superior–inferior). The mean deviation (MD) difference between the intereye was defined as the intereye MD asymmetry index (iMAI). Intereye visual-sensitivity difference within the same hemifield was calculated as the intereye hemifield visual-sensitivity asymmetry index. Functional progression was detected by Glaucoma Progression Analysis. The overall rate of MD change and the association between new indices were evaluated by linear regression. A Kaplan-Meier survival analysis was performed and the factors associated with glaucoma progression were evaluated by Cox proportional hazard modeling. Results Unilateral VFD eyes and bilateral VFD eyes within opposite VF hemifield showed significant progression and faster rate of MD change compared with bilateral VFD eyes within same VF hemifield (71.1% vs. 45.9% vs. 21.1% [P = 0.001]; –1.27 dB/y vs. −0.64 dB/y vs. −0.32 dB/y [P = 0.001]). Unilateral VFD eyes showed the fastest time to VF progression compared with other groups (P = 0.002). A faster rate of MD change was associated with greater intereye MD asymmetry index (P = 0.001) and greater intereye hemifield visual-sensitivity asymmetric index (P = 0.031), which were significant risk factors for glaucoma progression (all P < 0.001). Conclusions Among POAG eyes with comparable hemifield VFDs, eyes without a corresponding hemifield defect in the fellow eye showed faster rates of progression compared with those with a corresponding hemifield defect.

Discomfort provoked by normally innocuous visual stimuli has been reported by people with chronic pain. Visual discomfort may be higher in pain conditions in which central sensitization is implicated, such as Complex Regional Pain Syndrome (CRPS) and fibromyalgia. In an online study, we validated the Leiden Visual Sensitivity Scale (L-VISS) and Visual Discomfort Scale (VDS) in people with CRPS ( n = 57), fibromyalgia ( n = 75), and general chronic pain ( n = 53); investigated whether these groups and pain-free controls ( n = 125) differed in visual discomfort; and evaluated the effect of age. The L-VISS and VDS had good internal consistency. Both scales were positively related with experimentally induced visual distortions for mid-spatial frequency striped patterns, suggesting good construct validity. The scales were positively related with each other, and dissociated between the pain and pain-free groups in similar ways, suggesting good construct validity. There was no relationship between age and L-VISS scores and a small negative relationship between age and VDS scores. Visual discomfort was highest in the fibromyalgia group, followed by the CRPS group. This research confirms the utility of the L-VISS and VDS for measuring visual sensitivity in chronic pain and adds to evidence that central sensitization is an important mechanism of visual discomfort.

A central question in vision is whether spatial attention is represented in an eye-centered (retinotopic) or world-centered (spatiotopic) reference-frame. Most previous studies on this question focused on how coordinates are modulated across saccades. In the present study, we investigated the reference-frame of attention across smooth pursuit eye-movements using a goal-directed saccade task. In two experiments, participants were asked to pursue a moving target while attending to one or two grating stimuli. On each trial, one stimulus was constant in its retinal position and the other was constant in its spatial position. Upon detection of a slight change in stimulus orientation, participants were asked to stop pursuing and perform a fast saccade toward the modified stimulus. In the focused attention condition, they attended one, predefined, stimulus, and in the divided attention condition they attended both. In Experiment 1 the angle of the orientation change marking the target event was constant across participants and conditions. In Experiment 2, the angle was individually adapted to equate performance across participants and conditions. Findings of the two experiments were consistent and showed that the enhancement of mean visual sensitivity in the focused relative to the divided attention condition was similar in magnitude for both retinotopic and spatiotopic targets. This indicates that during smooth pursuit, endogenous attention was proportionally divided between targets in retinotopic and spatiotopic frames of reference.

Purpose: The recovery of visual sensitivity after a photobleach in early AMD is slowed in rods but cones also may be abnormal. The purpose of this article was to test different stimulus locations to investigate cone function and its relation to rod abnormalities.Methods: Stimuli were presented at two locations, 3.0° and 5.5°, in the inferior visual field. Post photobleach dark adaptation (DA) curves from 50 early-AMD patients were compared with those from 15 healthy controls of similar age. Curves were characterized in terms of four parameters: ct, cone threshold; α, the transition point from cone to rod function; S2, the slope of the second rod-mediated component; and β, the transition from the second to the third rod-mediated component.Results: There were strong location effects for the healthy group and the AMD group. Cone threshold was higher for the outer compared with the inner stimulus (P = 0.001), S2 was steeper for outer compared with inner (P < 0.001), α was shorter for outer (P = 0.004), and β was shorter for outer than inner (P = 0.002). The high variance in the patient data, particularly for α and β, explained the absence of a group*location interaction in the statistics.Conclusions: The data provide a novel perspective on abnormal cone- and rod-sensitivity recovery in early dry AMD. The comparison of pairs of DA curves from different locations highlights the involvement of cones in the underlying pathology of AMD. Dynamic measures of visual function are particularly sensitive to early AMD.

This research was funded by BBSRC grants BB/M001660/1 (JH), BB/M002543/1 (AW), and BB/M001210/1 (MB). Motion-in-depth can be detected by using two different types of binocular cues: change of disparity (CD) and inter-ocular velocity differences (IOVD). To investigate the underlying detection mechanisms, stimuli can be constructed that isolate these cues or contain both (FULL cue). Two different methods to isolate the IOVD cue can be employed: anti-correlated (aIOVD) and de-correlated (dIOVD) motion signals. While both types of stimuli have been used in studies investigating the perception of motion-in-depth, for the first time, we explore whether both stimuli isolate the same mechanism and how they differ in their relative efficacy. Here, we set out to directly compare aIOVD and dIOVD sensitivity by measuring motion coherence thresholds. In accordance with previous results [1], we found that motion coherence thresholds were similar for aIOVD and FULL cue stimuli for most participants. Thresholds for dIOVD stimuli, however, differed consistently from thresholds for the two other cues, suggesting that aIOVD and dIOVD stimuli could be driving different visual mechanisms. Publisher PDF

Ethambutol is a common cause of drug-related optic neuropathy. Prediction of the onset of ethambutol-induced optic neuropathy and consequent drug withdrawal may be an effective method to stop visual loss. Previous studies have shown that structural injury to the optic nerve occurred earlier than the damage to visual function. Therefore, we decided to detect structural biomarkers marking visual field loss in early stage ethambutol-induced optic neuropathy. The thickness of peripapillary retinal nerve fiber layer, macular thickness and visual sensitivity loss would be observed in 11 ethambutol-induced optic neuropathy patients (22 eyes) using optical coherence tomography. Twenty-four healthy age- and sex-matched participants (48 eyes) were used as controls. Results demonstrated that the temporal peripapillary retinal nerve fiber layer thickness and average macular thickness were thinner in patients with ethambutol-induced optic neuropathy compared with healthy controls. The average macular thickness was strongly positively correlated with central visual sensitivity loss (r (2) =0.878, P=0.000). These findings suggest that optical coherence tomography can be used to efficiently screen patients. Macular thickness loss could be a potential factor for predicting the onset of ethambutol-induced optic neuropathy.

Purpose To investigate the changes in macular blood flow and the correlation between those changes and central visual function in patients with retinitis pigmentosa (RP). Methods The mean blur rate (MBR), a quantitative blurring index of the laser speckle pattern that represents retinal and choroidal blood flow, was measured by laser speckle flowgraphy. Mean blur rate values in the macular area were compared between 70 patients with RP and 28 control subjects. The relationships between MBR on the one hand and, on the other, visual acuity (VA), mean deviation (MD) and averaged macular sensitivity of static perimetry tests (Humphrey Filed Analyzer, the central 10-2 program) were analysed in patients with RP. Results Macular MBR was decreased to 75% in patients with RP compared with control subjects (p

PURPOSE To investigate the effect of axial length (AL) on the structure-function relationship between retinal nerve fiber layer (RNFL) thickness measurements and visual field (VF) sensitivity measured with Goldmann III and V. METHOD There were 85 eyes of 85 patients with primary open angle glaucoma included in the current study. Optical coherence tomography and VF (Humphrey Field Analyzer 24-2 or 30-2) measurements with Goldmann III and V targets were carried out in all patients. The optic disc and the VF were divided into six clusters and the relationship between circumpapillary RNFL (cpRNFL) thickness and VF sensitivity (with Goldmann III or V), age, and AL were investigated in each cluster. RESULT Visual sensitivity with Goldmann III (19.3 ± 11.7 dB, mean ± standard deviation) was significantly lower than that with Goldmann V (24.6 ± 11.0 dB, P < 0.001, linear mixed model). Visual sensitivities with both Goldmann III and V were significantly correlated with cpRNFL thickness in all clusters. Visual sensitivity decreased with increasing AL in the nasal retinal area for both targets, however, this phenomenon was only observed with the Goldmann V target in the temporal area. CONCLUSION Visual sensitivity measured with the size V target decreases with increasing AL in the temporal area, which corresponds to the papillomacular bundle. In the nasal retinal area, visual sensitivity decreases with the increase of AL for both Goldmann III and Goldmann V. TRANSLATIONAL RELEVANCE Careful consideration is needed when measuring visual sensitivity using Goldmann V target in glaucomatous eyes with increased AL.

The effects of bilateral removal of inferotemporal cortex or lateral striate cortex are compared. The former operation impairs visual pattern discrimination learning, without disturbing prompt detection and retrieval of food, visual acuity or visual fields. In contrast, animals in which the macular striate projection area has been removed are significantly superior in tests of visual pattern discrimination learning despite showing impairment of visually guided reaching, visual acuity, and visual fields. The results indicate that the inferotemporal defect is not caused by deficient visual sensitivity or acuity.

Purpose Various methods have been used for testing peripheral visual field disturbances such as defects caused by drug toxicity. Static threshold perimetry with Humphrey Field Analyzer (HFA) is widely available. The aim of this study was to better define the normal thresholds for peripheral visual field (PVF) sensitivity and to refine analysis strategies. Methods Automated PVF testing was performed with HFA 60–4 program in 33 normal subjects. Test locations were organized into inner, middle, and outer eccentricity rings and divided into 4 zones: nasal, temporal, superior, and inferior. The threshold visual sensitivity (TVS) in decibels was established for each point. Results The majority of points with the lowest TVS and highest between-subject variability were located within the nasal area of the outer ring. Points with the highest TVS and least variability were detected in the inner ring and in the temporal area of the middle and outer rings. Mean zone TVS decreased and variability increased with increasing eccentricity. Conclusions The areas that demonstrate the highest between-subject consistency and thus might best reveal peripheral visual abnormalities with HFA 60–4 are the inner ring, inferior and temporal zone of the middle ring, and temporal zone of the outer ring. These observations may be useful for developing strategies to detect peripheral field loss at an early stage when central vision is not yet affected.

To investigate the relationship between anatomical changes and visual sensitivity in eyes with central serous chorioretinopathy (CSC).Twenty-one eyes with CSC were retrospectively studied using optical coherence tomography (OCT) retinal maps, line scan mode, and the Humphrey perimetry central 10-2 program.Total retinal thickness (TRT), including the neurosensory retina and subretinal fluid, correlated significantly with the sensitivity loss in the corresponding visual field in the central macula within a circle 6 mm in diameter. Differential analysis of the TRT, separating it into neurosensory retinal thickness (NRT) and subretinal thickness (SRT), revealed that only SRT correlated well with perimetric sensitivity at 1°, 3°, 5°, 7°, and 9° from the fovea along horizontal and vertical lines crossing at the fovea.Visual sensitivity measured with automated static perimetry is further attenuated by increasing distance between the photoreceptor and retinal pigment epithelium (RPE) in areas of serous retinal detachment in eyes with CSC.

Exposure to oriented luminance contrast patterns causes a reduction in visual sensitivity specifically for the adapter orientation. This orientation selectivity is probably the most studied aspect of contrast adaptation, but it has rarely been measured with steady-state visually evoked potentials (SSVEPs), despite their becoming one of the more popular methods of human neuroscience. Here, we measured orientation selective adaptation by presenting a plaid stimulus of which the horizontal and vertical grating reversed contrast at different temporal frequencies, while recording EEG signals from occipital visual areas. In three experiments, we compared SSVEP responses to the plaid before and after adaptation. All experiments showed a significant decrease in SSVEP response at the frequency of the adapter orientation, whereas such an effect was absent for the frequency of the orthogonal orientation. Adaptation also led to robust phase delays, selectively for the SSVEP frequency corresponding to the adapter orientation. These results demonstrate the efficiency of SSVEPs for measuring orientation selective adaptation; the method can measure changes in both amplitude and phase, simultaneously for two orientations.

Fifty-four normal tension glaucoma cases were studied to determine the value of several clinical tests for predicting the progression of the disease. Outflow facility, intraocular pressure (IOP) increase after water drinking, and diurnal changes in IOP were studied. Progression was determined on the basis of changes in visual sensitivity as measured on the Octopus 201. A minimum of four examinations of the central 30 degrees were conducted over a 3- to 7-year period. Progression of visual field defects was seen in 38.5% of eyes that had demonstrated some degree of abnormality in at least one of three clinical tests, while only 10.7% of those eyes that appeared normal on the basis of these tests showed such progression. The difference was significant (p

Purpose To compare the structure-function relationship between ganglion cell-inner plexiform layer (GCIPL) thickness measurements using spectral-domain optical coherence tomography (SDOCT) and visual sensitivities measured using standard automated perimetry (SAP) and microperimetry (MP) at the macula in glaucoma. Methods In a prospective study, 45 control eyes (29 subjects) and 60 glaucoma eyes (45 patients) underwent visual sensitivity estimation at the macula (central 10°) by SAP and MP, and GCIPL thickness measurement at the macula by SDOCT. Structure-function relationships between GCILP thickness and visual sensitivity loss with SAP and MP at various macular sectors were assessed using the Hood and Kardon model. To compare structure-function relationship with SAP and MP, we calculated the number of data points falling outside the 5th and the 95th percentile values of the Hood and Kardon model with each of the perimeters. Results The number of points falling outside the 5th and 95th percentile values of the Hood and Kardon model ranged from 28 (superior sector) to 48 (inferonasal sector) with SAP and 33 (superior sector) to 49 (inferonasal sector) with MP. The difference in the number of points falling outside the 5th and 95th percentile values with SAP and MP was statistically insignificant (P > 0.05, χ(2) test) for all the sectors. Conclusions Visual sensitivity measurements of both SAP and MP demonstrated a similar relationship with the GCIPL measurements of SDOCT at the macula in glaucoma.

Conventional static automated perimetry provides important clinical information, but its utility is limited by considerable test–retest variability. Fixational eye movements during testing could contribute to variability. To assess this possibility, it is important to know how much sensitivity change would be caused by a given eye movement. To investigate this, we have evaluated the gradient, the rate at which sensitivity changes with location. We tested one eye each, twice within 3 weeks, of 29 patients with glaucoma, 17 young normal subjects and 13 older normal subjects. The 10-2 test pattern with the SITA Standard algorithm was used to assess sensitivity at locations with 2° spacing. Variability and gradient were calculated at individual test locations. Matrix correlations were determined between variability and gradient, and were substantial for the patients with glaucoma. The results were consistent with a substantial contribution to test–retest variability from small fixational eye movements interacting with visual field gradient. Successful characterization of the gradient of sensitivity appears to require sampling at relatively close spacing, as in the 10-2 test pattern.

Primate vision is continuously disrupted by saccadic eye movements, and yet this disruption goes unperceived. One mechanism thought to reduce perception of this self-generated movement is saccadic suppression, a global loss of visual sensitivity just before, during, and after saccadic eye movements. The frontal eye field (FEF) is a candidate source of neural correlates of saccadic suppression previously observed in visual cortex, because it contributes to the generation of visually guided saccades and modulates visual cortical responses. However, whether the FEF exhibits a perisaccadic reduction in visual sensitivity that could be transmitted to visual cortex is unknown. To determine whether the FEF exhibits a signature of saccadic suppression, we recorded the visual responses of FEF neurons to brief, full-field visual probe stimuli presented during fixation and before onset of saccades directed away from the receptive field in rhesus macaques ( Macaca mulatta). We measured visual sensitivity during both epochs and found that it declines before saccade onset. Visual sensitivity was significantly reduced in visual but not visuomotor neurons. This reduced sensitivity was also present in visual neurons with no movement-related modulation during visually guided saccades and thus occurred independently from movement-related activity. Across the population of visual neurons, sensitivity began declining ∼80 ms before saccade onset. We also observed a similar presaccadic reduction in sensitivity to isoluminant, chromatic stimuli. Our results demonstrate that the signaling of visual information by FEF neurons is reduced during saccade preparation, and thus these neurons exhibit a signature of saccadic suppression.

Although once doubted, a consensus has emerged from the literature that visual sensitivity can be heightened locally with an appropriate precue. Experiments with partially and totally valid precues suggest an increase in sensitivity of less than one-half log unit at the precued position, as compared with other positions. New experiments with non-informative precues demonstrate that most of this small enhancement is not due to focal attention. Sensitivity can be heightened at eight positions simultaneously, just as much as when a single position is precued. Sensitivities produced by single, totally valid precues and single, non-informative precues were similar. Thus there seems to be no capacity limit for the effect of precues on visual sensitivity.

With progressively brighter stimuli, the amplitude of the photopic b-wave first increases, briefly saturates and then decreases gradually to reach a plateau, where the amplitude of the b-wave equals that of the a-wave; a phenomenon previously presented as the photopic hill. The unique presentation of this luminance-response function seriously complicates its analysis with curve fitting equations such as that of Naka–Rushton used for scotopic electroretinogram. We report a method of analysis of the photopic hill based on easily identifiable and reproducible features of the ascending and descending limbs of this function. The clinical usefulness of these parameters is illustrated with selected cases of retinal disorders.

Our state of arousal fluctuates from moment to moment-fluctuations that can have profound impacts on behavior. Arousal has been proposed to play a powerful, widespread role in the brain, influencing processes as far ranging as perception, memory, learning, and decision making. Although arousal clearly plays a critical role in modulating behavior, the mechanisms underlying this modulation remain poorly understood. To address this knowledge gap, we examined the modulatory role of arousal on one of the cornerstones of visual perception: contrast perception. Using a reward-driven paradigm to manipulate arousal state, we discovered that elevated arousal state substantially enhances visual sensitivity, incurring a multiplicative modulation of contrast response. Contrast defines vision, determining whether objects appear visible or invisible to us, and these results indicate that one of the consequences of decreased arousal state is an impaired ability to visually process our environment.

The contrast sensitivity function (CSF), a measure of visual sensitivity to a wide range of spatial frequencies, has been widely used as the gain profile of the front-end filter of the visual system to predict how we perceive spatial patterns. However, the CSF itself is determined by the gain profile and other processing inefficiencies of the visual system; it may be problematic to use the CSF as the gain profile in observer models. Here, we applied the external noise paradigm and the perceptual template model (PTM) to characterize several major properties of the visual system. With the external noise normalized gain profile, nonlinearity, and internal additive and multiplicative noises, the PTM accounted for 92.8% of the variance in the experiment data measured in a wide range of conditions and revealed the major processing components that determine the CSF. Unlike the CSF, the external noise normalized gain profile of the visual system is relatively flat across a wide range of spatial frequencies. The results may have major implications for understanding normal and abnormal spatial vision.

PURPOSE To evaluate scotopic retinal organization in retinopathy of prematurity (ROP) through a study of spatial summation. METHODS Thresholds for a range of stimulus diameters (0.4°-10°) were measured using a two alternative, spatial, forced choice psychophysical procedure. The critical diameter (DCRIT) for complete summation was estimated in subjects with a history of severe ROP (N = 7) and mild ROP (N = 17). Subjects who were born preterm and never had ROP (N = 16) and term-born subjects (N = 7) were also tested. The subjects ranged in age from 9 to 17 (median 13.5) years. RESULTS Critical diameter for complete spatial summation was significantly larger in ROP subjects than in subjects who never had ROP and in term-born control subjects. Critical diameter varied significantly with severity of ROP. CONCLUSIONS The larger DCRIT values in ROP are consistent with altered organization of the post receptor retina. This may offer the ROP retina a strategy for achieving noise reduction and good dark-adapted visual sensitivity.

High intraocular pressure, or glaucoma suspicion in children, requires to perform an automated visual field examination and to examine the optic nerve. These examinations are often difficult to realize in children, particularly those less than 6 years of age. From 6.5-7 years of age, visual sensitivity threshold is only marginally lower than that of adults, however due to the lack of established normative values for children, reference has to be based on adult normative values. Non mydriatic photographies of optic disc are a key element for follow up. Imaging technique (optical coherence tomography) produce reliable information, but difficult to interpret due to the absence of normative values adapted to children population.

Background/Method: Several studies have been performed to determine the effectiveness of oculokinetic perimetry (OKP) as a glaucoma screening test. In a previous study, we noted that OKP sensitivity and specificity was lower in mildly defective fields compared with moderately or severely, defective fields. In this study, we looked at visual fields with ‘glaucomatous’ defects. The visual field was divided into zones and points. The frequency of glaucomatous defects and visual sensitivity levels in these areas was recorded. The sensitivity and specificity of OKP to detect these defects were analysed. Results: Ninety-six glaucomatous fields from 57 subjects were assessed. An OKP chart testing the 8 to 16 degrees of eccentricity, and an extended nasal region, would cover all the defective fields present in this study. The 12–16 degree eccentricity zone has the best sensitivity (75%) and specificity (65%). Points within the nasal, inferior temporal and 8–12 degree eccentricity might be less sensitive, but 11(11.5%) fields had defects only in these areas. Zonal and point sensitivities and specificities were very similar, suggesting that fewer points could be used in each zone with similar results. Many of the eyes with false-negative OKP results had Humphrey Field Analyser visual sensitivity levels in the 10–18 dB range (i.e. associated with a mild or moderate defect). Decreasing the target stimulus might increase the detection rate of these milder defects; however, it might also increase overall false-positive rates. Our proposed experimental chart consists of two to four test points in each quadrant within the 12–16 degree of eccentricity, five within the 8–12 degree zone and two in the nasal region, and a central 1 or 1.5 mm black target. Conclusion: Analysis of results with modifications of the testing device may permit the OKP chart to achieve its full potential.

We measured the detectability of a single line (target) flanked by high-contrast inward- or outward-pointing arrowheads (context). We show that as a function of target contrast, context angle, and context position there is a continuum of contextual modulations of target detectability that vary from strong inhibition (target detection is impaired) to strong excitation (target detection is facilitated), but target detection is not affected when the context is presented at low contrasts. The results show striking correlations with the perceived length distortions in the Müller–Lyer illusion, i.e. an inward-pointing arrowhead results in improved target detectability and increased perceived length of the bar, whereas an outward-pointing arrowhead results in diminished target detectability and decreased perceived length of the bar. Both suppressive and facilitatory effects diminish as target contrast, arrowhead angle, and line-arrowhead spatial disparity are increased. At larger distances between line and arrowhead the suppressive effects become facilitatory (the Müller–Lyer illusion reverses). When concurrent Müller–Lyer extent experiments are run, we found that the perceived length of the target stimulus is overestimated or underestimated as it is flanked by high-contrast inward or outward-pointing arrowheads, the magnitude of the length distortion effects diminishing as target contrast increases. To explain the nature of both context-induced suppression and facilitation in contrast detection we present a population model of orientation detectors in visual cortex that relies on short and long-range horizontal cortical connections, and suggest that that the same type of mechanism that accounts for contrast detection may account for perceived extent.