Peripheral Contrast Sensitivity Research Articles

Contrast Sensitivity Is Impaired in Suspected Primary Open-Angle Glaucoma Patients.

To assess spatial contrast sensitivity (CS) in suspected primary open-angle glaucoma (POAG) patients. CS was measured using sinusoidal gratings of 4 cycles/degree. First, foveal and peripheral CS were assessed in 34 suspected POAG patients and compared with 71 and 28 age-matched healthy individuals for foveal and peripheral conditions, respectively. Second, foveal CS was assessed in 34 early POAG patients age-matched with suspected POAG patients. Analyses were performed considering two age ranges: Under and Over 50 y.o. Correlations were evaluated between CS and clinical parameters. Diagnostic accuracy was also analyzed. Peripheral CS was lower in older suspected POAG patients (23.4 ± 16.1) than the control group (39.1 ± 28.2) (p = 0.040). Foveal CS was reduced in suspected POAG participants (Under 50: 146.8 ± 63.3; p = 0.004. Over 50: 110.5 ± 65.0; p = 0.044) and in early POAG patients (Under 50: 141.2 ± 72.6; p = 0.002. Over 50: 80.2 ± 54.5 p < 0.001), both compared to the control group (Under 50: 213.5 ± 66.2. Over 50: 138.6 ± 71.7). CS was lower in early POAG than in POAG suspected in older patients (p = 0.042). Foveal CS was correlated with age (Early: p = 0.001. Suspect: p = 0.002) and with the cup-disc ratio only in early POAG patients (p < 0.001). Foveal CS had fair (AUC = 0.74) diagnostic accuracy for early POAG patients. CS in suspected POAG patients is lower than in healthy individuals. Our findings evidence the spatial vision loss before the onset of POAG.

Update on Clinical Trial Endpoints in Gene Therapy Trials for Inherited Retinal Diseases.

Inherited retinal diseases (IRDs) encompass a wide spectrum of rare conditions characterized by diverse phenotypes associated with hundreds of genetic variations, often leading to progressive visual impairment and profound vision loss. Multiple natural history studies and clinical trials exploring gene therapy for various IRDs are ongoing. Outcomes for ophthalmic trials measure visual changes in three main categories-structural, functional, and patient-focused outcomes. Since IRDs may range from congenital with poor central vision from birth to affecting the peripheral retina initially and progressing insidiously with visual acuity affected late in the disease course, typical outcome measures such as central visual acuity and ocular coherence tomography (OCT) imaging of the macula may not provide adequate representation of therapeutic outcomes including alterations in disease course. Thus, alternative unique outcome measures are necessary to assess loss of peripheral vision, color vision, night vision, and contrast sensitivity in IRDs. These differences have complicated the assessment of clinical outcomes for IRD therapies, and the clinical trials for IRDs have had to design novel specialized endpoints to demonstrate treatment efficacy. As genetic engineering and gene therapy techniques continue to advance with growing investment from industry and accelerated approval tracks for orphan conditions, the clinical trials must continue to improve their assessments to demonstrate safety and efficacy of new gene therapies that aim to come to market. Here, we will provide an overview of the current gene therapy approaches, review various endpoints for measuring visual function, highlight those that are utilized in recent gene therapy trials, and provide an overview of stage 2 and 3 IRD trials through the second quarter of 2024.

Central and peripheral contrast sensitivity in thyroid eye disease.

Assessment of central and peripheral contrast sensitivity (CS) in thyroid eye disease (TED) with and without dysthyroid optic neuropathy (DON). This cross-sectional study enrolled 33 eyes of 18 treatment-naïve TED patients and 18 age- and sex-matched healthy controls for comparative analysis. A detailed ophthalmic examination included visual acuity (VA), intraocular pressure measurement, slit-lamp biomicroscopy, and CS testing (central and four peripheral regions) using Spaeth-Richman Contrast Sensitivity test was done. The average age of TED patients was 47.17 ± 13.99 years and a female preponderance was noted (66.66%, n = 12). Twenty-five eyes (75.8%) were diagnosed as TED without DON, while eight eyes (24.2%) had DON. Nine eyes (27.2%) were in the active stage of disease and 29 eyes (87.8%) had proptosis. The difference in mean logMAR visual acuities between TED patients and controls was statistically insignificant ( P = 0.189), but a significant difference was noted in central and total CS score ( P < 0.001, Wilcoxon-Mann-Whitney test). On CS comparison between DON and non-DON eyes, a significant difference in average scores was noted in central and all peripheral areas ( P < 0.05, Wilcoxon-Mann-Whitney test). With increasing clinical activity score, a statistically significant reduction was noted in CS in three out of four peripheral regions (Spearman correlation, P < 0.05). Visual function compromise can be detected in TED in the presence of intact VA, by testing CS. Peripheral CS deteriorates with increasing inflammation and in DON. Serial monitoring of both central and peripheral CS may help in diagnosing DON early.

Peripheral spatial contrast sensitivity of the eyes

AIM: To develop a method for evaluating peripheral spatial contrast sensitivity and to use it in comparative studies of peripheral spatial contrast sensitivity in children with myopia under correction conditions with glasses with a highly aspherical lenslet (HAL) and single vision lenses (SVL).&#x0D; MATERIAL AND METHODS: A method for evaluating peripheral spatial contrast sensitivity was developed, in which visual control was carried out with the patients gaze fixed in the forward direction using a remote binocular autorefractometer, and the test image was sent to the selected area of the retina periphery. The SVL values were evaluated in three ranges of spatial frequencies, namely, low (0.52.0 cycle/deg), medium (4.0 to 8.0 cycle/deg), and high (11.3116.0 cycle/deg). Peripheral spatial contrast sensitivity was examined descriptively in 20 patients with low and moderate myopia. The age of the patients ranged from 8 to 13 (average, 11.41.5) years, and the degree of myopia ranged from 1.0 to 3.75 (average, 2.661.5 D). The patients were examined in glasses with HAL and in a trial frame with SVL correction.&#x0D; RESULTS. In HAL, which induces volumetric myopic defocus on the periphery of the retina, the peripheral spatial contrast sensitivity was lower than that in the SVL. This decrease was most pronounced at medium and high spatial frequencies, where it reached 3050%. The revealed differences in the peripheral spatial contrast sensitivity at high frequencies (8; 11.31 and 16 cycles/deg) were statistically significant: 7.5 and 10.8 at the frequency of 8 cycles/deg, 5.8 and 9.05 at the frequency of 11.31 cycles/deg, and 4.4 and 9.2 at the frequency of 16 cycles/deg, respectively.&#x0D; CONCLUSION: The peripheral spatial contrast sensitivity in glasses with rings of HAL, compared with the peripheral spatial contrast sensitivity in SVL, is significantly reduced at high spatial frequencies.

Assessing the contrast sensitivity function in myopic parafovea: A quick contrast sensitivity functions study.

PurposeCompare peripheral contrast sensitivity functions (CSF) between myopes and emmetropes to reveal potential myogenic risks during emmetropization.Materials and methodsThis observational, cross-sectional, non-consecutive case study included data from 19 myopes (23.42 ± 4.03 years old) and 12 emmetropes (22.93 ± 2.91 years old) who underwent central and peripheral quick CSF (qCSF) measurements. Summary CSF metrics including the cut-off spatial frequency (cut-off SF), area under log CSF (AULCSF), low-, intermediate-, and high-spatial-frequency AULCSFs (l-, i-, and h-SF AULCSFs), and log CS at 19 SFs in the fovea and 15 peripheral locations (superior, inferior, temporal, and nasal quadrants at 6, 12, 18, and 24° eccentricities, excluding the physiological scotoma at 18°) were analyzed with 3-way and 4-way between-subjects analysis of variance (ANOVA) (α = 0.05).ResultsThree-way ANOVA showed that myopes had significantly increased AULCSF at 6° (mean difference, 0.08; 95% CI, 0.02–0.13; P = 0.007) and 12° (mean difference, 0.09; 95% CI, 0.03–0.14; P = 0.003). Log CS at all 19 SFs were higher in the myopia group compared to the normal group (mean differencesuperior, 0.02; 95% CI, 0.01–0.20; P = 0.02 and mean differenceinferior, 0.11; 95% CI, 0.02–0.21; P = 0.01) at 12°. The h-SF AULCSF at 6° (mean differenceinferior, 1.27; 95% CI, 0.32–2.22; P = 0.009) and i-SF AULCSF at 12° (mean differencesuperior, 5.31; 95% CI, 4.35–6.27; P < 0.001; mean differenceinferior, 1.14; 95% CI, 0.19–2.10; P = 0.02) were higher in myopia vs. normal group.ConclusionWe found myopia increased contrast sensitivity in superior and inferior visual field locations at 6° parafoveal and 12° perifoveal regions of the retina. The observation of increased contrast sensitivities within the macula visual field in myopia might provide important insights for myopia control during emmetropization.

Effect of peripheral refractive errors on driving performance.

The effect of peripheral refractive errors on driving while performing secondary tasks at 40° of eccentricity was studied in thirty-one young drivers. They drove a driving simulator under 7 different induced peripheral refractive errors (baseline (0D), spherical lenses of +/- 2D, +/- 4D and cylindrical lenses of +2D and +4D). Peripheral visual acuity and contrast sensitivity were also evaluated at 40°. Driving performance was significantly impaired by the addition of myopic defocus (4D) and astigmatism (4D). Worse driving significantly correlated with worse contrast sensitivity for the route in general, but also with worse visual acuity when participants interacted with the secondary task. Induced peripheral refractive errors may negatively impact driving when performing secondary tasks.

Modification and evaluation of the peripheral contrast sensitivity function models.

We propose a series of modifications to the Barten contrast sensitivity function model for peripheral vision based on anatomical and psychophysical studies. These modifications result in a luminance pattern detection model that could quantitatively describe the extent of veridical pattern resolution and the aliasing zone. We evaluated our model against psychophysical measurements in peripheral vision. Our numerical assessment shows that the modified Barten leads to lower estimate errors than its original version.

The Effect of Peripheral Contrast Sensitivity Functions on the Performance of the Foveated Wavelet Image Quality Index

The Contrast Sensitivity Function (CSF) is an integral part of objective foveated image/video quality assessment metrics. In this paper, we investigate the effect of a new eccentricity-dependent CSF model on the performance of the foveated wavelet image quality index (FWQI). Our results do not show a considerable change in FWQI performance when it is evaluated against the LIVE-FBT-FCVR 2D dataset. We argue that the resolution of the head-mounted display used in the subjective experiment limits our ability to reveal the anticipated effect of the new CSF on FWQI performance.

Reflexive Saccades Used for Objective and Automated Measurements of Contrast Sensitivity in Selected Areas of Visual Field

PurposeThis study proposes a novel approach for objective and automated peripheral contrast sensitivity (CS) testing using reflexive saccades. Here the CS was examined in various areas the of visual field (VF) using a live analysis of gaze data. For validation of the new test, we examined CS with an established procedure of identifying the orientation of a contrast stimulus.MethodsTo perform and validate the saccade-based testing, two separate measurement events were performed. In the first, participants were asked to execute a saccade toward a newly-appeared stimulus in their VF. After the saccade execution or stimulus expiry, reporting the target orientation was required in a four-alternatives forced choice (4AFC). Therefore the first measurement yields two outcomes (objective and subjective). In the second measurement, only the identification of the stimulus orientation was requested, while fixating a central mark. Stimulus contrast was controlled by an adaptive psychometric procedure in both measurements.ResultsThe study found strong correlations (all r ≥ 0.79) of CS values for all three possible testing methods (saccade-based responding in saccadic measurements, keyboard-based responding in saccadic measurements, keyboard-based responding in non-saccadic measurements), showing the feasibility of employment of reflexive saccades in such testing. Second, this study shows a significant influence of eccentricity and direction of the stimulus on the CS function.ConclusionsCS measured with reflexive saccades is comparable to other testing methods over several areas of the participant's VF. Hence, we propose it as a novel and objective testing procedure for CS measurements.Translational RelevanceAssessment of CS using reflexive saccades extends the portfolio of suggested eye movement-based tests, allowing objective examination across the VF, which might be helpful especially in the early detection of various eye diseases.

Comparison of Central and Peripheral Contrast Sensitivity Between Healthy and Refractive Surgery Patients Using the Spaeth/Richman Contrast Sensitivity (SPARCS) Test.

To assess contrast sensitivity of central and peripheral vision with a newly developed, internet-based Spaeth/Richman Contrast Sensitivity (SPARCS) test in patients who underwent myopic photorefractive keratectomy (PRK) or femtosecond laser-assisted laser in situ keratomileusis (FSLASIK) refractive surgery in comparison with controls. In a retrospective study, a total of 186 eyes from 93 patients were analyzed: 62 eyes from 31 patients for each of the three groups under comparison. Patients who underwent a refractive surgery procedure and controls were evaluated using the SPARCS test. SPARCS scores were obtained for central and four peripheral areas (right upper, right lower, left upper, and left lower quadrants). Total, central, and peripheral SPARCS scores in patients with refractive surgery were compared with controls, adjusting for possible confounders. Multivariate and mixed linear regression models were used. Patients who had PRK had a lower score in all categories compared with the control group: by 5.9 points (95% CI: -9 to -2.8) in the total score, by 1.6 points (95% CI: -3 to -0.3) in the central score, and by 5.5 points (95% CI: -9.4 to -1.6) in the peripheral score. Patients who had FS-LASIK had non-statistically significant lower scores than the control group. PRK causes a decrease in central and peripheral contrast sensitivity. [J Refract Surg. 2022;38(2):128-133.].

Change in contrast sensitivity and OCT parameters in idiopathic intracranial hypertension.

Background:Deterioration in peripheral contrast sensitivity (CS) can be an indicator to detect progressive deterioration of visual function in patients with idiopathic intracranial hypertension (IIH).Objectives:The aim of this study was to evaluate the changes in central and peripheral CS and optical coherence tomography (OCT) parameters and in patients with IIH.Design and Methods:In this pilot observational study, data of 20 eyes of 10 ‘treatment-naïve’ IIH patients were analyzed. Detailed ocular examination was performed including CS assessment using both Pelli–Robson (PR) test and Spaeth–Richman Contrast Sensitivity Test (SPARCS) along with the OCT for macular and optic nerve head (ONH) parameters. A comparative analysis was done for CS and OCT parameters from baseline to a follow-up visit > 12 months (range: 18–24 months).Results:The study population had a female preponderance (80%, n = 8), and mean age at diagnosis was 31.9 ± 10.3 years. Mean follow-up period was 21.2 months (range: 15–24 months). At presentation, 6/6 visual acuity was noted in 75% eyes (n = 15) while all eyes had 6/6 vision at the last follow-up. Average PR score increased from 1.96 ± 0.36 to 2.30 at the last visit (Wilcoxon test: V = 0.0, p ⩽ 0.001) while average SPARCS score (total) increased from 71.85 ± 9.10 to 77.55 ± 6.20 (Paired t-test: t = −2.3, p = 0.035). Change in SPARCS score was significant in average total score (p = 0.035), and quadrant-wise score in superonasal (p = 0.014), inferonasal (p = 0.001), and inferotemporal (p = 0.021) quadrants. Same trend in SPARCS scores was observed when eyes with and without recurrence were analyzed. Statistically significant difference in retinal nerve fiber layer (RNFL) thickness (p = 0.007) and macular thickness (MT) in nasal quadrant (p = 0.006) was seen between the eyes with recurrence and without recurrence.Conclusion:Peripheral CS showed significant difference in all eyes over time. It showed significant change in eyes with recurrence, even in the presence of intact visual acuity and preserved central CS. Changes in RNFL thickness and nasal MT could differentiate eyes which developed recurrence from normal eyes.

Effect of laser peripheral iridotomy on contrast sensitivity using Spaeth/Richman Contrast Sensitivity test.

Background:Laser peripheral iridotomy (LPI) is the current standard of care for primary angle-closure glaucoma. The existing literature lacks evidence regarding the effects of LPI on contrast sensitivity (CS) after the procedure.Objective:This study evaluates central and peripheral CS in patients undergoing LPI using the computer-based, Spaeth/Richman Contrast Sensitivity (SPARCS) test.Methods:We performed a pilot, prospective, interventional cohort study including 30 patients of primary angle-closure suspect (PACS) or primary angle closure (PAC) in both eyes. LPI was performed after a detailed history and clinical examination using standard procedure in all eyes. Intraocular pressure (IOP) and CS testing using SPARCS was performed before, 2 weeks and 3 months after LPI.Results:Data analyses revealed female predominance (66.67%, 20/30); the mean age of enrolled patients was 49.93 ± 10.43 years, and presenting acuity was 0.02 ± 0.06 (Log of Minimum Angle of Resolution [LogMAR]). The mean vertical cup-to-disc ratio (VCDR), mean deviation (MD in dB) and pattern standard deviation (PSD in dB) were 0.34 ± 0.09, –2.36 ± 1.72 and 2.34 ± 0.81, respectively. There was a statistically significant decrease between the pre- (15.17 ± 3.83 mmHg) and 2 weeks post-LPI (11.70 ± 1.53 mmHg) IOP (p < 0.001). However, CS in the pre- (73.47 ± 9.88) and 3 months post-LPI (75.20 ± 11.98) SPARCS scores did not reveal any statistical difference. The group-wise analysis showed a similar trend between PAC and PACS patients.Conclusion:LPI does not affect central as well as peripheral CS assessment in patients with the primary angle-closure disease.

The impact of spectacle lenses for myopia control on visual functions.

PurposeSpectacle lenses containing multiple small peripheral elements have been developed for myopia control in children. It is important that their effect on vision be quantified by (i) fixation through the peripheral portion, thereby using foveal vision and (ii) by fixation through the central portion and presentation of peripheral targets.MethodsThe above approaches were used in five studies to evaluate two novel spectacle lens designs: spectacle lenses with Highly Aspherical Lenslets (HAL) and Slightly Aspherical Lenslets (SAL). A single vision lens served as a control. Visually normal adults participated in each study. The first two studies had subjects fixate through the periphery of the lenses. High and low (10%) contrast visual acuity was measured with the Freiburg Vision Test and reading speed for high and low contrast words measured with a sentence generator. The other three studies assessed peripheral vision while subjects fixated through the central portion of the lens. Peripheral contrast sensitivity was measured using two cycles per degree drifting Gabor stimuli. Peripheral motion perception was further evaluated using random dot stimuli. Finally, attention was measured using an established test of useful field of view with three levels of complexity.ResultsThe periphery of the HAL lens significantly reduced low contrast visual acuity, but not high contrast visual acuity, while the effect of the SAL lens was not significant for either. Neither test lens affected reading speed for high contrast words, but the HAL lens significantly affected performance for low contrast words. Neither test lens affected peripheral motion perception or useful field of view.ConclusionsLow contrast visual acuity and reading was slightly reduced while high contrast visual acuity was unaffected when fixating through the periphery of the novel lens designs. None of the peripheral measures of vision was affected by the novel lens designs.

Peripheral vision and hazard detection with average phakic and pseudophakic optical errors.

The impact of peripheral optical errors induced by intraocular lenses was evaluated by simulating the average phakic and pseudophakic image qualities. An adaptive optics system was used to simulate the optical errors in 20° nasal and inferior visual field in phakic subjects. Peripheral resolution acuity, contrast sensitivity and hazard detection were evaluated. Pseudophakic errors typical for monofocal designs had a negative effect on resolution acuity and contrast sensitivity and the hazard detection task also showed increased false positive and misses and a longer reaction time compared to phakic optical errors. The induced peripheral pseudophakic optical errors affect the peripheral visual performance and thereby impact functional vision.

Contrast sensitivity assessment for early detection of hydroxychloroquine toxicity.

Hydroxychloroquine (HCQ), is known to cause visual dysfunction during its prolonged course of administration. Optical Coherence Tomography (OCT) and field tests are the commonly used screening tests. Not much is known about the role of contrast sensitivity (CS) as method for early detection of HCQ toxicity. This pilot study was designed to study the change in central and peripheral contrast sensitivity for detecting early signs of HCQ toxicity. Prospective study conducted at Government Medical College & Hospital, Chandigarh, India. Twenty eyes of 10 treatment naïve, autoimmune patients. All patients underwent functional tests, contrast sensitivity tests: Pelli Robson and Spaeth Richman Contrast Sensitivity (SPARCS). Average and quadrant wise SPARCS score; Pelli Robson score and structural parameters viz., macular OCT parameters were compared at baseline, 3- and 6-month post treatment with HCQ. Change in CS using SPARCS and Pelli Robson were recorded at each visit and compared with the baseline. Structural and functional parameters were correlated. The average SPARCS scores at baseline, 3-month post HCQ and at 6-month post HCQ were 82.37 ± 8.40, 73.17 ± 9.63 and 70.37 ± 10.08, respectively. Quadrant wise change from first visit to third visit was statistically significant only in superotemporal (p = 0.002), inferotemporal (p = 0.02) and central (p = 0.01) quadrants. There was no correlation between SPARCS and Pelli Robson (S = 0.1454, p = 0.466). Similarly, there was no significant correlation between the structural and functional parameters. HCQ affect the CS by virtue of its action on bipolar and ganglion cells. Decrease in central and peripheral CS as measured by SPARCS can be a sign of early visual dysfunction, hence must be considered as an early indicator of HCQ toxicity.

Contrast sensitivity in Idiopathic Intracranial Hypertension.

Background: Idiopathic Intracranial Hypertension (IIH) is a disease of elevated intracranial pressure without any known cause. Visual dysfunction is the major morbidity of this disease but not much is known about the way the contrast sensitivity (CS) function is affected. Objective: This prospective, interventional study attempted to evaluate the change in central and peripheral contrast sensitivity, after treatment in patients diagnosed with IIH. Materials and methods: Twenty eyes of 10 IIH patients underwent an internet based, Spaeth Richman Contrast Sensitivity (SPARCS) test. Average and quadrant wise SPARCS scores were compared at presentation (treatment naïve), 1-month post treatment and 3 months post treatment. Results: The average SPARCS scores pre-treatment, 1-month post-treatment and at 3 months post treatment were 68.8 + 10.16, 74.45 + 11.17 and 75.7 + 10.81 respectively. At 3 months visit, the average SPARCS score was nearly comparable to the average score in normal Indian subjects, observed in a previous study of ours. Quadrant wise change in contrast sensitivity from first visit to third visit was significant in superonasal (p=0.003), inferonasal (p=0.029) and inferotemporal (p= 0.007) quadrants.Discussion: Effect of IIH on visual system is still a relatively unexplored area, especially in the Indians. Not many studies have concentrated on its impact on central as well as peripheral CS. Previous studies have hinted at a possible role of CS as a better indicator of visual dysfunction than other parameters. Conclusions: IIH affects both central and peripheral contrast sensitivity and therapy results in the improvement of contrast deficit. Poor contrast can possibly be explained by relatively more involvement of Magnocellular pathway over the Parvocellular pathway. Abbreviations: IIH = Idiopathic Intracranial Hypertension, CS = Contrast Sensitivity, SPARCS = Spaeth Richman Contrast Sensitivity Test, BMI = Body Mass Index, MC = Magnocellular pathway, PC = Parvocellular pathway

Triggering microsaccades by foveal motor error is sufficient to modulate peripheral visual sensitivity: neural and perceptual evidence

Visual processing is frequently interspersed with saccades, which are associated with strong peri-movement changes in neural and perceptual sensitivity. With fixed gaze, for controlled experiments on processes like covert attention, microsaccades still occur. During the past two decades, it became clear that microsaccades are not random (Hafed and Clark, 2002; Engbert and Kliegl, 2003), but instead exhibit predictable correlations with enhanced or decreased peripheral visual sensitivity (in multiple brain areas) and perception. These time-locked changes appear at eccentricities 1-2 orders of magnitude larger than the eye movement endpoints themselves. However, it remains unclear whether it is microsaccades, perhaps through their motor preparatory activity, that causally influence visual sensitivity, or whether visual sensitivity is itself modulated independently of microsaccades, maybe through oscillatory brain-state fluctuations; in this case, it is such modulations that “leak” into the motor system and trigger microsaccades. Here, motivated by (Hafed and Clark, 2002), in which no attentional effects were present in the absence of microsaccades, we tested the former hypothesis. We used real-time retinal image stabilization to introduce foveal motor errors at fixation (~0.06 deg) and causally drive microsaccades in an experimentally-controlled direction. We then presented peripheral (>5 deg) visual stimuli congruent or incongruent with microsaccade direction and recorded monkey superior colliculus (SC) activity. We found enhanced visual sensitivity and faster reaction times for microsaccade-congruent stimuli as a result of causally-generated microsaccades. In humans, we adapted a known task for pre-saccadic perceptual sensitivity (Rolfs & Carrasco, 2012) for microsaccades: subjects fixated, and we shifted the fixation spot by ~0.18 deg right or left to trigger microsaccades; the actual perceptual task (contrast comparison) was done for stimuli at 7 deg. Peripheral contrast sensitivity was enhanced before experimentally-manipulated microsaccades congruent with stimulus location, consistent with the neurophysiological results. Thus, foveal motor activity is sufficient to influence peripheral visual sensitivity.

Assessing glaucoma deterioration using Spaeth/Richman contrast sensitivity test.

Purpose:To assess changes in the central and peripheral contrast sensitivity in severe primary open-angle glaucoma (POAG) patients using a computer-based Spaeth/Richman contrast sensitivity test (SPARCS) over a period of 24 months.Methods:Our pilot, observational study included 15 patients (30 eyes) with severe POAG. Visual acuity, intraocular pressure, number of anti-glaucoma drugs, visual fields, and SPARCS score were recorded at first visit and at 12 and 24 months.Results:We observed changes in mean deviation (MD) from −19.37 ± 5.04 to −20.63 ± 4.07, mean pattern standard deviation (PSD) from 11.49 ± 2.61 to 11.35 ± 2.01, and mean SPARCS score from 54.97 ± 15.66 to 53.50 ± 16.42. We found no statistically significant difference between visual field parameters and SPARCS scores associated with the number or type of prescribed anti-glaucoma drugs. Spearman’s correlation coefficient of SPARCS at baseline (SPARCS1) versus MD at baseline (MD1) was 0.274 (p = 0.142) and SPARCS1 versus PSD at baseline (PSD1) was −0.163 (p = 0.389). The correlation coefficient between SPARCS at 12 months (SPARCS2) versus MD (MD2) at the same time point was computed to be 0.391 (p = 0.03), whereas SPARCS2 versus PSD at 12 months was −0.212 (p = 0.262). Similarly, we found the coefficient to be 0.336 (p = 0.069) for SPARCS3 (SPARCS at 24 months) versus MD3 (MD at 24 months) and −0.242 (p = 0.197) for SPARCS3 versus PSD3 (PSD at 24 months). Correlation coefficients between SPARCS1/2, SPARCS1/3, MD1/2, MD1/3 PSD1/2, and PSD1/3 were 0.856, 0.865, 0.748, 0.722, 0.497, and 0.562, respectively (p < 0.001). MD changed by 9.46% ± 12.73%, PSD by 0.64% ± 14.03%, and average SPARCS by 3.31% ± 12.73% over 24 months.Conclusion:The data from our study indicate the utilitarian application of SPARCS, an inexpensive and readily available tool for monitoring functional deterioration in cases with advanced glaucomatous damage, especially in resource-poor settings. Furthermore, it is a useful and reliable alternative to the imaging modalities where retinal nerve fiber layer measurement can be erroneous in advanced cases secondary to the floor effect.

Contrast sensitivity and visual acuity in subjects wearing multifocal contact lenses with high additions designed for myopia progression control

ObjectivesTo assess the visual performance of multifocal contact lenses (MFCLs) with high addition powers designed for myopia control. MethodsTwenty-four non-presbyopic adults (mean age 24 years, range 18–36 years) were fitted with soft MFCLs with add powers of +2.0 D (Add2) and +4.0 D (Add4) (RELAX, SwissLens) and single vision lenses (SVCL; Add0) in a counterbalanced order. In this double-masked study, half of the participants were randomly fitted with 3 mm-distance central zone MFCLs while the other half received 4.5 mm-distance central zone MFCLs. Visual acuity was measured at distance (3.0 m) and at near (0.4 m). Central and peripheral contrast sensitivity was evaluated at distance using the Gabor patch test. The area under the logarithmic contrast sensitivity function curve (ALCSF) was calculated and compared between the groups (i.e. different additions powers used). ResultsNear and distance visual acuities were not affected by the lenses, neither Add2 nor Add4, when compared to Add0, however, CZ3 significantly reduced distance visual acuity with Add4 when compared to CZ4.5 (−0.08 logMAR vs. for CZ3 and -0.18 logMAR for CZ4.5, p = 0.013).MFCLs impaired central ALCSF only when Add2 was used (15.99 logCS for Add2 and 16.36 logCS for SVCLs, p = 0.021). Peripheral ALCSF was statistically lower for both addition powers of the MFCLs when compared to SVCLs (12.70 for Add2 and Add4, 13.73 for SVCLs, p = 0.009). The above effects were the same for both central zones used. ConclusionsMFCLs with CZ3 diameter and high add power (Add4) slightly reduced distance visual acuity when compared to CZ4.5 but no reduction in this parameter was found with medium add power (Add2). Central contrast sensitivity was impaired only by MFCLs with the lower add power (Add2). Both add powers in the MFCLs reduced peripheral contrast sensitivity to a similar extent.

Peripheral resolution and contrast sensitivity: effects of monochromatic and chromatic aberrations.

Correction and manipulation of peripheral refractive errors are indispensable for people with central vision loss and in optical interventions for myopia control. This study investigates further enhancements of peripheral vision by compensating for monochromatic higher-order aberrations (with an adaptive optics system) and chromatic aberrations (with a narrowband green filter, 550 nm) in the 20° nasal visual field. Both high-contrast detection cutoff and contrast sensitivity improved with optical correction. This improvement was most evident for gratings oriented perpendicular to the meridian due to asymmetric optical errors. When the natural monochromatic higher-order aberrations are large, resolution of 10% contrast oblique gratings can also be improved with correction of these errors. Though peripheral vision is mainly limited by refractive errors and neural factors, higher-order aberration correction beyond conventional refractive errors can still improve peripheral vision under certain circumstances.