Contrast Sensitivity Function Acuity Research Articles

Association between contrast sensitivity function and structural damage in primary open-angle glaucoma

AimsTo evaluate the association between contrast sensitivity function (CSF) and glaucomatous structural damage in primary open-angle glaucoma (POAG).MethodsA cross-sectional study was performed with 103 patients (103 eyes) aged 25–50 years...

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

PurposeThis study is to investigate the contrast sensitivity function (CSF) using the quick CSF (qCSF) test in Chinese adults with myopia.MethodsThis 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.ResultsThe 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).ConclusionsThe 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.

Meridian-Specific and Post-Optical Deficits of Spatial Vision in Human Astigmatism: Evidences From Psycho-Physical and EEG Scalings

Previous studies have demonstrated that orientation-specific deprivation in early life can lead to neural deficits of spatial vision in certain space, and can even result in meridional amblyopia (MA). Individuals with astigmatism are the optimal and natural models for exploring this asymmetric development of spatial vision in the human visual system. This study aims to assess the contrast sensitivity function (CSF) and EEG signals along two principal meridians in participants with regular astigmatism when being optimal optical corrected. Twelve participants with astigmatism (AST group, 20 eyes) and thirteen participants with (MA group, 19 eyes) were recruited in the current study. CSFs and spatial sweep visual evoked potentials (sVEP) were measured with vertical and horizontal sinewave gratings along two principal meridians monocularly. Area under log CSF (AULCSF), spatial frequency threshold corresponding to 80% contrast gratings (SF threshold at 80% ctr), and CSF acuity were calculated from CSF test. In addition, sVEP amplitudes and thresholds were calculated with the recursive least square method. Participants with astigmatism exhibited marked vertical-horizontal resolution disparities even after they were corrected with optimal optical corrections. CSF tests showed that AULCSF along weak meridian (measured with horizontal gratings) was lower than that along strong meridian (measured with vertical gratings) in both groups. Significant meridional disparity of CSF acuity was also found in both groups. In addition, the MA group showed larger meridional disparity compared to the AST group. Spatial sVEP thresholds also supported the existence of marked meridional disparity. Our results suggest that meridian-specific partial deprivation in early life might lead to monocularly asymmetric development of spatial vision in the human visual system. In terms of application, we tested the feasibility and reliability of adopting psychophysical and EEG scalings to investigate the asymmetric development of spatial vision related to astigmatism. These paradigms are potentially applicable to reduce and even eliminate the meridional disparity in the primary visual cortex by adopting perceptual learning or other vision-related interventions.

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

BackgroundImpairment 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).ObjectiveTo 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.MethodsWe 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.ResultsWe 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).ConclusionHigh precision, usability, repeatability, and discrimination support the qCSF as a tool to assess contrast vision in pwMS.

New Precision Metrics for Contrast Sensitivity Testing.

Visual sensitivity is comprehensively described by the contrast sensitivity function (CSF), but current routine clinical care does not include its assessment because of the time-consuming need to estimate thresholds for a large number of spatial frequencies. The quick CSF method, however, dramatically reduces testing times by using a Bayesian information maximization rule. We evaluate the test-retest variability of a tablet-based quick CSF implementation in a study with 100 subjects who repeatedly assessed their vision with and without optical correction. We first discuss two commonly used measures of repeatability, intraclass correlation and the Bland-Altman Coefficient of Repeatability, and show that they are vulnerable to artifacts. Instead, we propose to formulate precision as an information retrieval task: from all repeat test scores, can we retrieve a certain individual based on their first test score? We then use rank-based analyses such as mean average precision as a better measure to compare different test metrics, and show that the highest test-retest precision is achieved using a summary statistic, the area under the log CSF (AULCSF). This demonstrates the benefit of assessment of the whole CSF compared to sensitivity at individual spatial frequencies only. AULCSF also yields best discrimination performance (99.2%) between measurements that were taken with and without glasses, respectively, even better than CSF Acuity. The tablet-based quick CSF thus enables the rapid and reliable home monitoring of visual function, which has the potential to improve early diagnosis and treatment of ophthalmic pathologies such as diabetic retinopathy or age-related macular degeneration.