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Abstract Purpose To compare the characteristics of the quantitative contrast sensitivity function (qCSF) in eyes with early keratoconus (Early-KC) and normal control (NC) eyes and investigate the associated factors. Design A cross-sectional study. Methods This study included 43 eyes of 43 patients with Early-KC (including subclinical keratoconus [SKC] and forme fruste keratoconus [FFKC]) and 77 NC eyes of 77 participants with corrected distance visual acuity (CDVA) all ≥ 20/20. Contrast sensitivity (CS) was assessed using the qCSF tests. Subgroup analysis was performed according to keratoconus type(SKC and FFKC) and astigmatism(cylindrical refraction >-1.0D or ≤-1.0D). Results Sex ratio, spherical refraction, and spherical equivalent (SE) varied significantly between the two groups (all P

Abstract We developed and validated digital twins (DTs) for contrast sensitivity function (CSF) across 12 prediction tasks using a data-driven, generative model approach based on a hierarchical Bayesian model (HBM). For each prediction task, we utilized the HBM to compute the joint distribution of CSF hyperparameters and parameters at the population, subject, and test levels. This computation was based on a combination of historical data (N = 56), any new data from additional subjects (N = 56), and “missing data” from unmeasured conditions. The posterior distributions of the parameters in the unmeasured conditions were used as input for the CSF generative model to generate predicted CSFs. In addition to their accuracy and precision, these predictions were evaluated for their potential as informative priors that enable generation of synthetic quantitative contrast sensitivity function (qCSF) data or rescore existing qCSF data. The DTs demonstrated high accuracy in group level predictions across all tasks and maintained accuracy at the individual subject level when new data were available, with accuracy comparable to and precision lower than the observed data. DT predictions could reduce the data collection burden by more than 50% in qCSF testing when using 25 trials. Although further research is necessary, this study demonstrates the potential of DTs in vision assessment. Predictions from DTs could improve the accuracy, precision, and efficiency of vision assessment and enable personalized medicine, offering more efficient and effective patient care solutions.

BackgroundAge-related vision changes significantly contribute to fatal crashes at night among older drivers. However, the effects of lighting conditions on age-related vision changes and associated driving performance remain unclear. ObjectiveThis pilot study examined the associations between visual function and driving performance assessed by a high-fidelity driving simulator among drivers 60 and older across 3 lighting conditions: daytime (photopic), nighttime (mesopic), and nighttime with glare. MethodsActive drivers aged 60 years or older participated in visual function assessments and simulated driving on a high-fidelity driving simulator. Visual acuity (VA), contrast sensitivity function (CSF), and visual field map (VFM) were measured using quantitative VA, quantitative CSF, and quantitative VFM procedures under photopic and mesopic conditions. VA and CSF were also obtained in the presence of glare in the mesopic condition. Two summary metrics, the area under the log CSF (AULCSF) and volume under the surface of VFM (VUSVFM), quantified CSF and VFM. Driving performance measures (average speed, SD of speed [SDspeed], SD of lane position (SDLP), and reaction time) were assessed under daytime, nighttime, and nighttime with glare conditions. Pearson correlations determined the associations between visual function and driving performance across the 3 lighting conditions. ResultsOf the 20 drivers included, the average age was 70.3 years; 55% were male. Poor photopic VA was significantly correlated with greater SDspeed (r=0.26; P

Iconic memory and short-term memory are not only crucial for perception and cognition, but also of great importance to mental health. Here, we first showed that both types of memory could be improved by improving limiting processes in visual processing through perceptual learning. Normal adults were trained in a contrast detection task for ten days, with their higher-order aberrations (HOA) corrected in real-time. We found that the training improved not only their contrast sensitivity function (CSF), but also their iconic memory and baseline information maintenance for short-term memory, and the relationship between memory and CSF improvements could be well-predicted by an observer model. These results suggest that training the limiting component of a cognitive task with visual perceptual learning could improve visual cognition. They may also provide an empirical foundation for new therapies to treat people with poor sensory memory.

Perceptual learning (PL) can significantly improve human performance in perceptual tasks primarily through template reweighting. Previous studies have documented how PL changes perceptual template in stimulus feature space. We investigated how PL reweights visual information in time. With a dynamic external noise paradigm and the elaborated perceptual template model (ePTM) analysis, we found that training with an orientation identification task in the zero external noise condition reduced contrast thresholds in both zero and high external noise conditions, whereas training in the high external noise condition only reduced contrast thresholds in high external noise conditions. The ePTM analysis showed that training in both zero and high external noise changed the overall amplitude, but not the shape of the temporal window of the perceptual template to exclude external noise across time, and training in zero external noise additionally reduced additive internal noise. Our results provided additional constraints for models of PL.

Aims To evaluate the association between contrast sensitivity function (CSF) and glaucomatous structural damage in primary open-angle glaucoma (POAG). Methods A cross-sectional study was performed with 103 patients (103 eyes) aged 25-50 years who had POAG without any other ocular disease. CSF measurements were obtained by the quick CSF method, a novel active learning algorithm that covers 19 spatial frequencies and 128 contrast levels. The peripapillary retinal nerve fibre layer (pRNFL), macular ganglion cell complex (mGCC), radial peripapillary capillary (RPC) and macular vasculature were measured by optical coherence tomography and angiography. Correlation and regression analyses were used to assess the association of area under log CSF (AULCSF), CSF acuity and contrast sensitivities at multiple spatial frequencies with structural parameters. Results AULCSF and CSF acuity were positively associated with pRNFL thickness, RPC density, mGCC thickness and superficial macular vessel density (p<0.05). Those parameters were also significantly associated with contrast sensitivity at 1, 1.5, 3, 6, 12, 18 cycles per degree spatial frequencies (p<0.05) and, the lower the spatial frequency, the higher the correlation coefficient. RPC density (p=0.035, p=0.023) and mGCC thickness (p=0.002, p=0.011) had significant predictive value for contrast sensitivity at 1 and 1.5 cycles per degree, with adjusted R2 of 0.346 and 0.343, respectively. Conclusions Full spatial frequency contrast sensitivity impairment, most notably at low spatial frequencies, is a characteristic change in POAG. Contrast sensitivity is a potential functional endpoint for the measurement of glaucoma severity. [ABSTRACT FROM AUTHOR]