Associations of quantitative contrast sensitivity with wide-field swept-source optical coherence tomography angiography in retinal vein occlusion.

PURPOSE: To investigate associations between contrast sensitivity (CS) and vascular metrics on wide-field swept-source optical coherence tomography angiography (WF-SS-OCTA) in patients with retinal vein occlusion (RVO). METHODS: This prospectively recruited, cross-sectional observational study included RVO patients who underwent quantitative CS function (qCSF) testing and WF-SS-OCTA using 3 × 3, 6 × 6, and 12 × 12 mm angiograms on the same day. The study measured several qCSF outcomes and WF-SS-OCTA vascular metrics, including vessel density (VD), vessel skeletonized density (VSD), and foveal avascular zone (FAZ). The data were analyzed using multivariable regression analysis controlling for age and central subfield thickness (CST). RESULTS: A total of 43 RVO eyes of 43 patients and 30 fellow eyes were included. In RVO eyes, multiple vascular metrics were associated with CS outcomes but not visual acuity (VA). On 12 × 12 images, CS thresholds at 1 cpd, 1.5 cpd, and 3 cpd were significantly associated with VD and VSD, but VA was not. When comparing standardized regression coefficients, we found that vascular metrics had a larger effect size on CS than on VA. For instance, the standardized beta coefficient for FAZ area and CS at 6 cpd (ß* = - 0.46, p = 0.007) was larger than logMAR VA (ß* = 0.40, p = 0.011). CONCLUSION: Microvascular changes on WF-SS-OCTA in RVO had a larger effect size on CS than VA. This suggests CS may better reflect the microvascular changes of RVO compared to VA. qCSF-measured CS might be a valuable adjunct functional metric in evaluating RVO patients.

Structure-function association between contrast sensitivity and retinal thickness (total, regional, and individual retinal layer) in patients with idiopathic epiretinal membrane.

PURPOSE: To investigate structure-function associations between retinal thickness, visual acuity (VA), and contrast sensitivity (CS), using the quantitative contrast sensitivity function (qCSF) method in patients with idiopathic epiretinal membrane (ERM). METHODS: Retrospective, cross-sectional observational study. Patients with a diagnosis of idiopathic ERM were included. Patients underwent complete ophthalmic examination, spectral-domain optical coherence tomography imaging (SD-OCT) (SPECTRALIS® Heidelberg), and CS testing using the qCSF method. Outcomes included area under the log CSF (AULCSF), contrast acuity (CA), and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). RESULTS: A total of 102 eyes of 79 patients were included. Comparing standardized regression coefficients, retinal thickness in most ETDRS sectors was associated with larger reductions in AULCSF, CA, and CS thresholds at 3 and 6 cpd than those in logMAR VA. These differences in effect on VA and CS metrics were more pronounced in the central subfield and inner ETDRS sectors. Among the retinal layers, increased INL thickness had the most detrimental effect on visual function, being significantly associated with reductions in logMAR VA, AULCSF, CA, and CS thresholds at 3 and 6 cpd (all p < .01), as well as at 1.5 and 12 cpd (p < .05). CONCLUSION: Retinal thickness seems to be associated with larger reductions in contrast sensitivity than VA in patients with ERM. Measured with the qCSF method, contrast sensitivity may serve as a valuable adjunct visual function metric for patients with ERM.

A novel quick contrast sensitivity function test in Chinese adults with myopia and its related parameters.

PURPOSE: This study is to investigate the contrast sensitivity function (CSF) using the quick CSF (qCSF) test in Chinese adults with myopia. METHODS: This case series study included 320 myopic eyes of 160 patients (mean age 27.75 ± 5.99 years) who underwent a qCSF test for acuity, area under log CSF (AULCSF), and mean contrast sensitivity (CS) at 1.0, 1.5, 3.0, 6.0, 12.0, and 18.0 cycle per degree (cpd). Spherical equivalent, corrected-distant visual acuity (CDVA), and pupil size were recorded. RESULTS: The spherical equivalent, CDVA (LogMAR), spherical refraction, cylindrical refraction, and the scotopic pupil size of the included eyes were - 6.30 ± 2.27 D (- 14.25 to - 0.88 D), 0 ± 0.02, - 5.74 ± 2.18 D, - 1.11 ± 0.86 D, and 6.77 ± 0.73 mm, respectively. The AULCSF and CSF acuity were 1.01 ± 0.21 and 18.45 ± 5.39 cpd, respectively. The mean CS (log units) at six different spatial frequencies were 1.25 ± 0.14, 1.29 ± 0.14, 1.25 ± 0.14, 0.98 ± 0.26, 0.45 ± 0.28, and 0.13 ± 0.17, respectively. A mixed effect model showed significant correlations between age and acuity, AULCSF, and CSF at 1.0, 12.0, and 18.0 cpd. Interocular CSF differences were correlated with the interocular difference of spherical equivalent, spherical refraction (at 1.0 cpd, 1.5 cpd), and cylindrical refraction (at 12.0 cpd, 18.0 cpd). The lower cylindrical refraction eye had higher CSF compared with the higher cylindrical refraction eye (0.48 ± 0.29 vs. 0.42 ± 0.27 at 12.0 cpd and 0.15 ± 0.19 vs. 0.12 ± 0.15 at 18.0 cpd). CONCLUSIONS: The age-related decrease in contrast sensitivity is at low and high spatial frequencies. Higher-degree myopia may show a decrease in CSF acuity. Low astigmatism was noted to affect the contrast sensitivity significantly.

Second-order visual sensitivity in the aging population.

Most visual and cognitive functions are affected by aging over the lifespan. In this study, our aim was to investigate the loss in sensitivity to different classes of second-order stimuli-a class of stimuli supposed to be mainly processed in extrastriate cortex-in the aging population. These stimuli will then allow one to identify specific cortical deficit independently of visibility losses in upstream parts of the visual pathway. For this purpose, we measured the sensitivity to first-order stimuli and second-order stimuli: orientation-modulated, motion-modulated or contrast-modulated as a function of spatial frequency in 50 aged participants. Overall, we observed a sensitivity loss for all classes of stimuli, but this loss differentially affects the three classes of second-order stimuli tested. It involves all modulation spatial frequencies in the case of motion modulation, but just high modulation spatial frequencies in the case of contrast- and orientation modulations. These observations imply that aging selectively affects the sensitivity to second-order stimuli depending on their type. Since there is evidence that these different second-order stimuli are processed in different regions of extrastriate cortex, this result may suggest that some visual cortical areas are more susceptible to aging effects than others.

Quick contrast sensitivity measurements in the periphery.

Measuring the contrast sensitivity function (CSF) in the periphery of the eye is complicated. The lengthy measurement time precludes all but the most determined subjects. The aim of this study was to implement and evaluate a faster routine based on the quick CSF method (qCSF) but adapted to work in the periphery. Additionally, normative data is presented on neurally limited peripheral CSFs. A peripheral qCSF measurement using 100 trials can be performed in 3 min. The precision and accuracy were tested for three subjects under different conditions (number of trials, peripheral angles, and optical corrections). The precision for estimates of contrast sensitivity at individual spatial frequencies was 0.07 log units when three qCSF measurements of 100 trials each were averaged. Accuracy was estimated by comparing the qCSF results with a more traditional measure of CSF. Average accuracy was 0.08 log units with no systematic error. In the second part of the study, we collected three CSFs of 100 trials for six persons in the 20° nasal, temporal, inferior, and superior visual fields. The measurements were performed in an adaptive optics system running in a continuous closed loop. The Tukey HSD test showed significant differences (p < 0.05) between all fields except between the nasal and the temporal fields. Contrast sensitivity was higher in the horizontal fields, and the inferior field was better than the superior. This modified qCSF method decreases the measurement time significantly and allows otherwise unfeasible studies of the peripheral CSF.

A normative framework for the study of second-order sensitivity in vision.

While the contrast sensitivity approach has been successful in evaluating the processing of first-order stimuli, there is a need to develop comparable ways of assessing second-order vision. Our purpose here is to establish normative data on second-order contrast-, orientation-, and motion-modulation sensitivity in humans. We propose a unified framework, applying the quick contrast sensitivity function (qCSF) method, which was recently developed for the rapid measurement of contrast sensitivity across the full spatial-frequency range (Lesmes, Lu, Baek, & Albright, 2010), to measure both first- and second-order sensitivity functions. We first show that the qCSF methodology can be successfully adapted to different kinds of first- and second-order measurements. We provide a normative dataset for both first- and second-order sensitivity, and we show that the sensitivity to all these stimuli is equal in the two eyes. Our results confirm some strong differences between first- and second-order processing, in accordance with the classical filter-rectify-filter model. They suggest a common contrast detection mechanism but different second-order mechanisms.

Decreased Macular Choriocapillaris Perfusion Correlates with Contrast Sensitivity Function in Dry Age-Related Macular Degeneration.

PURPOSE: To investigate the relationships between contrast sensitivity (CS), choriocapillaris perfusion, and other structural OCT biomarkers in dry age-related macular degeneration (AMD). DESIGN: Cross-sectional, observational study. PARTICIPANTS: One hundred AMD eyes (22 early, 52 intermediate, and 26 late) from 74 patients and 45 control eyes from 37 age-similar subjects. METHODS: All participants had visual acuity (VA) assessment, quantitative CS function (qCSF) testing, macular OCT, and 6 × 6-mm swept-source OCT angiography scans on the same day. OCT volumes were analyzed for subretinal drusenoid deposits and hyporeflective drusen cores, and to measure thickness of the outer nuclear layer. OCT angiography scans were utilized to calculate drusen volume and inner choroid flow deficit percentage (IC-FD%), and to measure the area of choroidal hypertransmission defects (HTDs). Inner choroid flow deficit percentage was measured from a 16-µm thick choriocapillaris slab after compensation and binarization with Phansalkar's method. Generalized linear mixed-effects models were used to evaluate the associations between functional and structural variables. MAIN OUTCOME MEASURES: To explore the associations between qCSF-measured CS, IC-FD%, and various AMD imaging biomarkers. RESULTS: Age-related macular degeneration exhibited significantly reduced qCSF metrics eyes across all stages compared with controls. Univariate analysis revealed significant associations between various imaging biomarkers, reduced qCSF metrics, and VA in both groups. Multivariate analysis confirmed that higher IC-FD% in the central 5 mm was significantly associated with decreases in all qCSF metrics in AMD eyes (ß = -0.74 to -0.25, all P < 0.05), but not with VA (P > 0.05). Outer nuclear layer thickness in the central 3 mm correlated with both VA (ß = 2.85, P < 0.001) and several qCSF metrics (ß = 0.01-0.90, all P < 0.05), especially in AMD eyes. Further, larger HTD areas were associated with decreased VA (ß = -0.89, P < 0.001) and reduced CS at low-intermediate frequencies across AMD stages (ß = -0.30 to -0.29, P < 0.001). CONCLUSIONS: The significant association between IC-FD% in the central 5 mm and qCSF-measured CS reinforces the hypothesis that decreased macular choriocapillaris perfusion contributes to visual function changes in AMD, which are more pronounced in CS than in VA. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Active Learning to Characterize the Full Contrast Sensitivity Function in Cataracts.

Background: To characterize contrast sensitivity function (CSF) in cataractous and pseudophakic eyes compared to healthy control eyes using a novel quantitative CSF test with active learning algorithms. Methods: This is a prospective observational study at an academic medical center. CSF was measured in eyes with visually significant cataract, at least 2+ nuclear sclerosis (NS) and visual acuity (VA) ≥ 20/50, in pseudophakic eyes and in healthy controls with no more than 1+ NS and no visual complaints, using the Manifold Contrast Vision Meter. Outcomes included Area under the Log CSF (AULCSF) and CS thresholds at 1, 1.5, 3, 6, 12, and 18 cycles per degree (cpd). A subgroup analysis as performed on cataract eyes with VA ≥ 20/25. Results: A total of 167 eyes were included, 58 eyes in the cataract group, 77 controls, and 32 pseudophakic eyes with respective median AULCSF of 1.053 (0.352) vs 1.228 (0.318) vs 1.256 (0.360). In our multivariate regression model, cataract was associated with significantly reduced AULCSF (P= 0.04, ß= -0.11) and contrast threshold at 6 cpd (P= 0.01, ß= -0.16) compared to controls. Contrast threshold at 6 cpd was significantly reduced even in the subgroup of cataractous eyes with VA ≥ 20/25 (P=0.02, ß=-0.16). Conclusion: The novel qCSF test detected disproportionate significant contrast deficits at 6 cpd in cataract eyes; this remained significant even in the cataractous eyes with VA ≥ 20/25. CSF testing may enhance cataract evaluation and surgical decision-making, particularly in patients with subjective visual complaints despite good VA.

Tolerance to lens tilt and decentration of two multifocal intraocular lenses: using the quick contrast sensitivity function method.

BACKGROUND: Quick contrast sensitivity function (qCSF) method is an advanced quick method for contrast sensitivity function (CSF) evaluation. This study evaluated the contrast sensitivity (CS) of eyes undergoing cataract surgery with multifocal intraocular lens (IOL) implantation and its tolerance to IOL tilt and IOL decentration using the qCSF method. METHODS: Patients undergoing uneventful phacoemulsification and a trifocal IOL (Zeiss AT LISA tri 839MP, Carl Zeiss, Germany) or an extended depth-of-focus (EDOF) IOL (Tecnis Symfony ZXR00, Johnson & Johnsons, USA) implantation were included. Monocular contrast sensitivity was measured using the qCSF method at one month post-surgery. IOL tilt and decentration were measured using an optical aberrometer (OPD-Scan III, NIDEK, Japan). RESULTS: Seventy-two patients/eyes with the 839MP IOL and 64 patients/eyes with the ZXR00 IOL were included. Area under the log CSF (AULCSF) and CS acuity did not differ significantly between the two groups. The ZXR00 IOL group showed better CS at 1 cpd (1.137 ± 0.164 vs. 1.030 ± 0.183 logCS) and 1.5 cpd (1.163 ± 0.163 vs. 1.071 ± 0.161 logCS), while the 839MP IOL group had better CS at 6 cpd (0.855 ± 0.187 vs. 0.735 ± 0.363 logCS). In the 839MP IOL group, all CSF metrics were negatively correlated with IOL tilt (all P < 0.05), while in the ZXR00 IOL group, the CS at 3 cpd had no significant correlation with IOL tilt (P > 0.05). Among myopic eyes, fewer CSF metrics were negatively correlated with IOL tilt in the ZXR00 IOL group than in the 839MP IOL group. No significant correlation was found between CSF metrics and IOL decentration. CONCLUSIONS: The ZXR00 and the 839MP IOL groups presented comparable CSF. CS was negatively correlated with IOL tilt, instead of decentration in multifocal IOLs, particularly among myopic eyes. The ZXR00 IOL had better tolerance to IOL tilt in myopic eyes.

Contrast Sensitivity Is Associated With Chorioretinal Thickness and Vascular Density of Eyes in Simple Early-Stage High Myopia.

Objective: To evaluate the contrast sensitivity function (CSF), chorioretinal thickness and vascular density as well as their relationships in subjects with simple early-stage high myopia. Methods: Eighty-one young subjects were enrolled in this study. They were categorized into the simple high myopia group (sHM, n = 51) and the low-moderate myopia group (control group, n = 30). Monocular CSF under best correction was measured with the qCSF method. Retinal superficial and deep vascular density, inner and outer retinal thickness and choroidal thickness were measured using optical coherence tomography angiography. Results: The area under log CSF (AULCSF) and cutoff spatial frequency (Cutoff SF) of the sHM group were significantly reduced compared to those of the control group (P = 0.003 and P < 0.001, respectively). The parafoveal and perifoveal retinal thickness, deep vascular density and choroidal thickness were also significantly reduced in the sHM group (all P < 0.05). Multiple regression analysis revealed that AULCSF was significantly correlated with retinal deep vascular density, outer retinal thickness in the parafoveal and perifoveal areas (all P < 0.05). Conclusion: Compared to low to moderate myopic eyes, patients with simple high myopia have thinner retinal and choroidal thickness, lower retinal vascular density, and reduced contrast sensitivity. Moreover, the CSF was correlated with the measures of chorioretinal structure and vasculature. The results suggest that the CSF is a sensitive functional endpoint in simple early-stage high myopia.

Contrast Sensitivity Deficits and Its Structural Correlates in Fuchs Uveitis Syndrome.

Purpose: To investigate the deficits in contrast sensitivity in patients with Fuchs uveitis syndrome (FUS) and to explore the potential relationship between contrast sensitivity and ocular structure. Methods: In this prospective study, 25 patients with FUS and 30 healthy volunteers were recruited. Eyes were divided into three groups: FUS-affected eyes (AE), fellow eyes (FE), and healthy eyes. The contrast sensitivity function (CSF) of all participants was evaluated using the quick CSF (qCSF) method. Fundus photographs were collected for the analysis of refractive media, and vascular density (VD) was assessed using optical coherence tomography angiography (OCTA). Data were analyzed and compared using the generalized estimating equation (GEE). Results: The CSF of AE was significantly lower than that of FE and controls, while no significant difference was observed between FE and controls. Contrast sensitivity was negatively correlated with the grade of haze. No significant correlation was found between visual function and VDs in FUS eyes. Conclusions: We found that the CSF of FUS-affected eyes was significantly reduced, and the visual impairment was predominantly caused by the refractive media turbidity.

Validation of Computer-Adaptive Contrast Sensitivity as a Tool to Assess Visual Impairment in Multiple Sclerosis Patients.

BACKGROUND: Impairment of visual function is one of the major symptoms of people with multiple sclerosis (pwMS). A multitude of disease effects including inflammation and neurodegeneration lead to structural impairment in the visual system. However, the gold standard of disability quantification, the expanded disability status scale (EDSS), relies on visual assessment charts. A more comprehensive assessment of visual function is the full contrast sensitivity function (CSF), but most tools are time consuming and not feasible in clinical routine. The quantitative CSF (qCSF) test is a computerized test to assess the full CSF. We have already shown a better correlation with visual quality of life (QoL) than for classical high and low contrast charts in multiple sclerosis (MS). OBJECTIVE: To study the precision, test duration, and repeatability of the qCSF in pwMS. In order to evaluate the discrimination ability, we compared the data of pwMS to healthy controls. METHODS: We recruited two independent cohorts of MS patients. Within the precision cohort (n = 54), we analyzed the benefit of running 50 instead of 25 qCSF trials. The repeatability cohort (n = 44) was assessed by high contrast vision charts and qCSF assessments twice and we computed repeatability metrics. For the discrimination ability we used the data from all pwMS without any previous optic neuritis and compared the area under the log CSF (AULCSF) to an age-matched healthy control data set. RESULTS: We identified 25 trials of the qCSF algorithm as a sufficient amount for a precise estimate of the CSF. The median test duration for one eye was 185 s (range 129-373 s). The AULCSF had better test-retest repeatability (Mean Average Precision, MAP) than visual acuity measured by standard high contrast visual acuity charts or CSF acuity measured with the qCSF (0.18 vs. 0.11 and 0.17, respectively). Even better repeatability (MAP = 0.19) was demonstrated by a CSF-derived feature that was inspired by low-contrast acuity charts, i.e., the highest spatial frequency at 25% contrast. When compared to healthy controls, the MS patients showed reduced CSF (average AULCSF 1.21 vs. 1.42, p < 0.01). CONCLUSION: High precision, usability, repeatability, and discrimination support the qCSF as a tool to assess contrast vision in pwMS.

Measuring the Contrast Sensitivity Function in Non-Neovascular and Neovascular Age-Related Macular Degeneration: The Quantitative Contrast Sensitivity Function Test.

Age-related macular degeneration (AMD) affects various aspects of visual function compromising patients' functional vision and quality of life. Compared to visual acuity, contrast sensitivity correlates better with vision-related quality of life and subjectively perceived visual impairment. It may also be affected earlier in the course of AMD than visual acuity. However, lengthy testing times, coarse sampling and resolution, and poor test-retest reliability of the existing contrast testing methods have limited its widespread adoption into routine clinical practice. Using active learning principles, the qCSF can efficiently measure contrast sensitivity across multiple spatial frequencies with both high sensitivity in detecting subtle changes in visual function and robust test-retest reliability, emerging as a promising visual function endpoint in AMD both in clinical practice and future clinical trials.

Active Learning of Contrast Sensitivity to Assess Visual Function in Macula-off Retinal Detachment.

PURPOSE: To characterize the contrast sensitivity function (CSF) in patients with successful repair of macula-off rhegmatogenous retinal detachment (RD) using an adaptive computerized contrast testing device. METHODS: CSF was prospectively measured in macula-off RD patients following successful repair and age-matched controls at W. K. Kellogg Eye Center and Massachusetts Eye and Ear, employing the active learning device Manifold Contrast Vision Meter (Adaptive Sensory Technology, San Diego, CA). Outcome measures included average area under the CSF curve (AULCSF), CS thresholds at 1-18 cycles per degree (cpd) and best correctd visual acuity (BCVA) in RD eyes fellow eyes and controls. A sub-analysis was performed in eyes with BCVA of 20/30 or better. RESULTS: Twenty-three macula-off RD eyes status post repair, fellow healthy eyes and 45 age-matched control eyes underwent CSF testing. The mean BCVA of the 23 RD eyes was 0.250 logMAR, significantly reduced compared to fellow eyes 0.032 (p<0.001) and controls 0.026 (p< 0.00001). There was a statistically significant reduction in AULCSF in RD eyes compared to the fellow eyes (p<0.0001) and to age-matched controls (Z-score -0.90, p<0.0001) and CSF reduction across all spatial frequencies. In the 15 RD eyes with BCVA of 20/30 or better, the mean CSF was significantly reduced compared to fellow eyes (p=0.0158) and controls (p=0.0453). CONCLUSIONS: CSF in macula-off RD eyes following repair was significantly reduced compared to fellow eyes and age-matched controls. CSF seems to be a promising visual function endpoint with potential applications in the clinical practice and future clinical trials.

Interocular suppressive interactions in amblyopia depend on spatial frequency.

In amblyopia, there is an interocular suppressive imbalance that results in the fixing eye dominating perception. In this study, we aimed to determine whether these suppressive interactions were narrowband and tuned for spatial frequency or broadband and independent of spatial frequency. We measured the contrast sensitivity and masking functions of fifteen amblyopic subjects and seventeen control subjects using the quick Contrast Sensitivity Function (qCSF) approach (Lesmes, Lu, Baek, & Albright, 2010). We first measured the monocular sensitivity functions of each participant and thereafter corrected for it. We then measured masking sensitivity functions for low, mid and high spatial frequency masks, normalized to their visibility. In the control group, we observed that the strength of dichoptic masking is equivalent between the two eyes. It is also tuned such that masking by low spatial frequencies in one eye mainly affects low spatial frequencies in the other eye and masking by high spatial frequencies mainly affects high spatial frequencies. In amblyopes, although the interocular masking is also tuned for spatial frequency, it is not equivalent between the two eyes: the masking effect from the amblyopic to fixing eye is weaker than the other way around. The asymmetry observed in the strength of masking between the two eyes in amblyopia is tuned for spatial frequency. It is not the consequence of the contrast sensitivity deficit of the amblyopic eye nor is it the consequence of abnormally strong masking from the fixing eye. Rather it is due to an abnormally weak masking strength by the amblyopic eye per se.

Measuring the Contrast Sensitivity Function Using the qCSF Method With 10 Digits.

PURPOSE: The Bayesian adaptive quick contrast sensitivity function (qCSF) method with a 10-letter identification task provides an efficient CSF assessment. However, large populations are unfamiliar with letters and cannot benefit from this test. To overcome the barrier, we conducted this study. METHOD: A new font for digits (0∼9) was created. The digits were then filtered with a raised cosine filter, rescaled to different sizes to cover spatial frequencies from 0.5 to 16 cycles per degree (cpd), and used as stimuli in a 10-alternative forced choice (10AFC) digit identification task. With the 10AFC digit identification task, the CSFs of five young and five old observers were measured using the qCSF and Psi methods. The estimates from the latter served as reference. RESULTS: The new digit font showed significantly improved similarity structure, Levene's test, F(1, 88) = 6.36, P = 0.014. With the 10-digit identification task, the CSFs obtained with the qCSF method matched well with those obtained with the Psi method (root mean square error [RMSE] = 0.053 log10 units). With approximately 30 trials, the precision of the qCSF method reached 0.1 log10 units. With approximately 75 trials, the precision of the CSFs obtained with the qCSF was comparable to that of the CSFs measured by the Psi method in 150 trials. CONCLUSIONS: The qCSF with the 10 digit identification task is validated for both young and old observers. TRANSLATIONAL RELEVANCE: The qCSF method with the 10-digit identification task provides an efficient and precise CSF test especially for people who are unfamiliar with letters.

The amblyopic deficit for 2nd order processing: Generality and laterality.

A number of previous reports have suggested that the processing of second-order stimuli by the amblyopic eye (AE) is defective and that the fellow non-amblyopic eye (NAE) also exhibits an anomaly. Second-order stimuli involve extra-striate as well as striate processing and provide a means of exploring the extent of the cortical anomaly in amblyopia using psychophysics. We use a range of different second-order stimuli to investigate how general the deficit is for detecting second-order stimuli in adult amblyopes. We compare these results to our previously published adult normative database using the same stimuli and approach to determine the extent to which the detection of these stimuli is defective for both amblyopic and non-amblyopic eye stimulation. The results suggest that the second-order deficit affects a wide range of second-order stimuli, and by implication a large area of extra-striate cortex, both dorsally and ventrally. The NAE is affected only in motion-defined form judgments, suggesting a difference in the degree to which ocular dominance is disrupted in dorsal and ventral extra-striate regions.

A normative dataset on human global stereopsis using the quick Disparity Sensitivity Function (qDSF).

Global stereopsis results from the lateral displacement of distributed textured elements between the eyes. In this study, we investigate how the key parameters of the disparity sensitivity function such as its peak sensitivity and spatial bandwidth are distributed across a pool of normal observers and how large the individual differences are. For this purpose, we adapted the quick Contrast Sensitivity Function (qCSF, Lesmes et al., 2010) to the quick Disparity Sensitivity Function (qDSF). We show that this new method is accurate and allows a rapid measurement of disparity sensitivity for a range of different disparity spatial frequencies. Our results confirm that there is a greater variability in human disparity sensitivity tuning compared to other common visual features, for example, 1st or 2nd order contrast sensitivity.