The effect on income of providing near vision correction to workers in Bangladesh: The THRIVE (Tradespeople and Hand-workers Rural Initiative for a Vision-enhanced Economy) randomized controlled trial.

INTRODUCTION: Presbyopia, the leading cause of vision impairment globally, is common during working years. However, no trials have assessed presbyopia's impact on income. METHODS: In April 2017, we conducted a census among 59 Bangladesh villages to identify persons aged 35 to 65 years with presbyopia (presenting distance vision > = 6/12 bilaterally and correctable inability to see 6/13 at 40 cm with both eyes), who never had owned glasses. Participants were randomized (1:1) to receive immediate free reading glasses (intervention) or glasses delivered 8 months later (control). Visual demand of different jobs was stratified into three levels. Outcomes were between-group differences in the 8 month change in: self-reported monthly income (primary) and Near Vision Related Quality of Life (NVRQOL, secondary). RESULTS: Among 10,884 census participants, 3,655 (33.6%) met vision criteria and 863 (23.6%) comprised a sample enriched for near vision-intensive jobs, but 39 (4.52%) could not be reached. All participants allocated to intervention (n = 423, 51.3%) and control (n = 401, 48.7%) received the appropriate intervention, and follow-up was available for 93.4% and 96.8% respectively. Groups were similar at baseline in all characteristics: mean age was 47 years, 50% were male, 35% literate, and about half engaged in "most near vision-intensive" occupations. Glasses wear at 8-month follow-up was 88.3% and 7.81% in intervention and control respectively. At baseline, both the intervention and control groups had a self-reported median monthly income of US$35.3. At endline, the median income for the intervention group was US$47.1 compared with US$35.3 for control, a difference of 33.4%. Predictors of greater income increase in multivariate models included intervention group allocation (OR 1.45, 95% CI 1.12, 1.88, P = 0.005), male sex (OR 2.41, 95% CI 1.84, 3.16, P <0.001), and not engaging in income-producing work at baseline (OR 2.35, 95% CI 1.69, 3.26, P<0.001). CONCLUSION: Provision of reading glasses increases income in near vision-intensive occupations, and may facilitate return to work for those currently unemployed.

Needs and views on eye health and women's empowerment and theory of change map: implication on the development of a women-targeted eyecare programme for older Zanzibari craftswomen.

OBJECTIVES: To assess needs and views regarding eye health and empowerment from craftswomen's perspectives to develop a theory of change (ToC) for a women-targeted eyecare programme. MATERIAL AND METHODS: Eighteen stakeholders participated in a 2-day consultation workshop in Zanzibar. The composition was (1) 15 women and 3 men; (2) Unguja (n=8), Pemba (n=6) and Tanzania mainland (n=4) and (3) craftswomen (n=14) and governmental stakeholders (n=4). Thematic analysis determined the craftswomen's needs and views regarding eye health and empowerment and subsequently inputs, activities, outputs, outcomes and impact to develop the programme's initial ToC. In refining the initial ToC, we used insights from a qualitative study suggesting that improved near vision is perceived by craftswomen as a potential source of empowerment across economic, psychological, social, political and educational dimensions. RESULTS: The eye conditions experienced by the craftswomen were eye irritation caused by foreign bodies, the need for near spectacles and other eye morbidities. They were advised by the cooperatives to visit eye health centres for treatment. The main barriers to accessing services were inaccessibility and unaffordability of eye services and a lack of eye health knowledge and practices. Nineteen subthemes on women empowerment (economic n=4, social n=4, psychological n=6, education n=2 and political n=3) were obtained. We created a ToC on how investing in improving craftswomen near vision could achieve empowerment. CONCLUSION: The participants provided insights into their needs and how they would like the eyecare programme to be implemented and how they see they could be empowered in the process.

2022 Glenn A. Fry Award lecture: Enhancing clinical assessment for improved ophthalmic management.

ABSTRACT: Detailed clinical assessment is critical to allow sensitive evaluation of the eye and its management. As technology advances, these assessment techniques can be adapted and refined to improve the detection of pathological changes of ocular tissue and their impact on visual function. Enhancements in optical medical devices including spectacle, contact, and intraocular lenses have allowed for a better understanding of the mechanism and amelioration of presbyopia and myopia control. Advancements in imaging technology have enabled improved quantification of the tear film and ocular surface, informing diagnosis and treatment strategies. Miniaturized electronics, large processing power, and in-built sensors in smartphones and tablets capacitate more portable assessment tools for clinicians, facilitate self-monitoring and treatment compliance, and aid communication with patients. This article gives an overview of how technology has been used in many areas of eye care to improve assessments and treatment and provides a snapshot of some of my studies validating and using technology to inform better evidence-based patient management.

Computational methodology to support functional vision assessment in premature infants: A viability study.

BACKGROUND: Premature newborns have a higher risk of abnormal visual development and visual impairment. OBJECTIVE: To develop a computational methodology to help assess functional vision in premature infants by tracking iris distances. METHODS: This experimental study was carried out with children up to two years old. A pattern of image capture with the visual stimulus was proposed to evaluate visual functions of vertical and horizontal visual tracking, visual field, vestibulo-ocular reflex, and fixation. The participants' visual responses were filmed to compose a dataset and develop a detection algorithm using the OpenCV library allied with FaceMesh for the detection and selection of the face, detection of specific facial points and tracking of the iris positions is done. A feasibility study was also conducted from the videos processed by the software. RESULTS: Forty-one children of different ages and diagnoses participated in the experimental study, forming a robust dataset. The software resulted in the tracking of iris positions during visual function evaluation stimuli. Furthermore, in the feasibility study, 8 children participated, divided into Pre-term and Term groups. There was no statistical difference in any visual variable analyzed in the comparison between groups. CONCLUSION: The computational methodology developed was able to track the distances traveled by the iris, and thus can be used to help assess visual function in children.

A novel multisensory device for the assessment and rehabilitation of perceptual and attentional competencies.

The present study aims to assess a novel technological device suitable for investigating perceptual and attentional competencies in people with or without sensory impairment. The TechPAD is a cabled system including embedded sensors and actuators to enable visual, auditory, and tactile interactions and a capacitive surface receiving inputs from the user. The system is conceived to create multisensory environments, using multiple units controlled separately and simultaneously. We assessed the device by adapting a spatial attention task comparing performances in different cognitive load conditions (high or low) and stimulation (unimodal, bimodal, or trimodal). 28 sighted adults were asked to monitor both the central and peripheral parts of the device and to tap a target stimulus (either visual, auditory, haptic, or multimodal) as fast as they could. Our results suggest that this new device can provide congruent and incongruent multimodal stimuli and quantitatively measure parameters such as reaction time and accuracy, allowing to investigate perceptual mechanisms in multisensory environments.Clinical Relevance-The TechPad is a reliable tool for the assessment of spatial attention during interactive tasks. its application in clinical trials will pave the way to its role in multisensory rehabilitation.

Validation of the Austin Assessment: A screening tool for cerebral visual impairment related visual issues.

Cerebral visual impairment is the most common cause of vision impairment affecting children in the economically developed world with a prevalence rate of approximately 3.4%. Currently there are limited options for screening for cerebral visual impairment, resulting in many children going undiagnosed, especially those that have normal visual acuity. The aim of this research was to validate an iPad App called the Austin Assessment, which was developed as a potential screening tool for cerebral visual impairment related visual issues. The research involved three separate phases: (1) creating a database of normative ranges for children aged 5-18 across the different variables of the Austin Assessment, (2) using the Austin Assessment to screen children aged 5-13 to assess the effectiveness of the Austin Assessment as a screening tool for CVI related visual issues, and (3) conducting specific validation research assessing children using the Austin Assessment and an already validated visual search tool. Each phase used different quantitative research methodologies to help show the effectiveness of the Austin Assessment as a screening tool for cerebral visual impairment related visual issues. From phase one of the research, thresholds were established for three variables of the Austin Assessment for the age groupings of 5-8, 9-12 and 13-18. If a child meets one of these thresholds this indicates further assessment is required to determine if they do in fact have cerebral visual impairment related visual issues. Phase two identified 17 children out of 270 who had clinical findings indicating visual issues; potentially indicative of CVI; investigation into the nature of these visual issues is ongoing. Phase three found that the Austin Assessment has moderate diagnostic value for each age group, with good sensitivity and specificity, making it effective at distinguishing those children who have visual issues from those who have typical vision. Further investigation is needed to confirm this initial validation.

Further Validation of Comfortable Print Size as a Parameter for Clinical Low-Vision Assessment.

Purpose: Comfortable print size (CfPS) has been proposed as a clinical alternative to deriving critical print size (CPS) in the assessment of reading function of vision-impaired patients. This study aimed to assess the repeatability of CfPS and to compare assessment duration and values to CPS measures and acuity reserves. Methods: Thirty-four adults with vision impairment had their reading function assessed. Two assessments of CfPS were made by asking, "What is the smallest print size that you would find comfortable using?" Reading parameters including CPS were determined using the MNREAD card chart and MNREAD app. Results: CfPS was quicker to assess (mean ± SD, 144 ± 77 seconds) than the MNREAD card (231 ± 177 seconds) or app (285 ± 43 seconds). Within-session repeatability of CfPS showed no significant bias or variation across the functional range and limits of agreement (LoA) of ±0.09 logMAR. CfPS values were 0.10 logMAR larger than card CPS values, but no different from app CPS values, with LoA of ±0.43 to 0.45 logMAR. Acuity reserve (comparing CfPS to card reading acuity) was 1.9:1 on average, with a maximum of 5.0:1. Conclusions: CfPS offers a quick, repeatable, and individualized clinical measure of the print size required for sustained reading that reflects CPS values obtained by more traditional measures. Translational Relevance: CfPS is an appropriate clinical measure of reading function to use in determining the magnification requirements of vision impaired patients for sustained reading tasks.

Beam-Shaping Extended Depth of Focus Intraocular Lens: Optical Assessment With Corneas of Increasing Spherical Aberration.

PURPOSE: To assess the optical quality and halo formation of a beam-shaping extended depth-of-focus (EDOF) intraocular lens (IOL) (AcrySof IQ Vivity; Alcon Laboratories, Inc) with corneas of long-range spherical aberration (SA) such as those resulting from myopic laser ablations. METHODS: The optical quality of the EDOF IOL and a reference monofocal IOL was evaluated with three corneas (A, B, and C, with SA =+0.135, +0.290, +0.540 µm, respectively, for a 5.15-mm pupil at the IOL plane). The through-focus modulation transfer function area (MTFa) curves were obtained between -5.00 and +2.00 diopters (D) defocus range. The halo was also assessed with the three corneas. RESULTS: Through-focus MTFa curves for a 4.5-mm IOL pupil showed a slight decrease in the maximum MTFa value provided by the EDOF IOL compared to the monofocal IOL in the three corneal situations (A: 45.9 vs 38.6 units; B: 41.1 vs 33.1 units, and C: 26.9 vs 23.8 units). For the 3.0-mm pupil, the EDOF IOL also had lower maximum MTFa than the monofocal IOL; however, the depth-of-focus increased to -2.20 D. With corneas A and B, the halo induced was of low energy with both IOLs. With cornea C, the EDOF IOL created a much larger and intense halo. CONCLUSIONS: The EDOF IOL provided a good distance optical performance and an extended range of focus of approximately 2.00 D, with a halo of low intensity when evaluated with a corneal SA similar to the one induced by a low to moderate myopic ablation. With a high myopic ablation, the halo induced would be of considerable size and energy. [J Refact Surg. 2023;39(2):95-102.].

Assessment of digital light processing (DLP) projector stimulators for visual electrophysiology.

INTRODUCTION: Visual electrophysiology tests require the use of precise and calibrated visual display units (VDUs). Existing VDUs for presenting structured stimuli are now mostly obsolete, with modern solutions limited or unsuitable for clinical testing. Digital light processing (DLP) laser projectors have recently become commercially available and this study aimed to assess their suitability as VDUs for visual electrophysiology testing. METHODS: This study consisted of two sections. The first was a photometric study of two DLP laser projectors (Viewsonic LS831WU and HiSense 100L5FTUK) to assess luminance, contrast, spectral and temporal characteristics of the stimulus. The second was a physiological study comparing pattern electroretinograms (PERG) and visual evoked potentials (PVEPs) amplitudes and peak-times recorded using a DLP laser projector, photometrically and spatially matched to existing plasma VDUs at our institution (Pioneer Electronics Corporation, PDP422MXE). RESULTS: The Viewsonic DLP laser projector was capable of high luminance levels (0-587.5 cd/m2) whilst maintaining contrast above 93%. The temporal properties showed fast rise and fall times of 0.5-1 ms and 0.5-1 ms, respectively, without any transient luminance change with reversals. The device required a warm-up time of at least 2 min until reaching near maximal luminance. The second (Hisense) device was observed to have a detrimental input lag jitter so was not used for any further analysis. PERGs and PVEPs showed high agreement and correlation (r = 0.766-0.905) between the Viewsonic DLP device and existing plasma VDUs. No significant differences were observed for P50 and P100 peak-time (p = > 0.05), however P50, N95 and P100 amplitudes were all significantly larger for the DLP device (p = < 0.05). DISCUSSION: The DLP laser projector tested in this study is a viable and practical replacement VDU for clinical electrophysiology tests of vision. The device is easily capable of meeting ISCEV standards, and showed PERG and PVEP amplitudes larger than existing systems despite photometric and spatial matching. The DLP laser projectors are capable of very large field sizes so are beneficial for paediatric testing or those wishing to examine large field responses. Importantly, it was observed that some devices may suffer input lag jitter, therefore, individual calibration and assessment of DLP projection systems is an important consideration before clinical implementation.

[Application progress of quality of life assessment scales and psychological assessment tools for evaluating overall quality of life in patients with uveitis].

Uveitis is a common sight-threatening ocular disease that has multiple heterogeneous clinical entities, complicated pathogenesis, and a high complication rate. The visual impairment caused by uveitis, the side effects of long-term systemic therapy, and the economic burden due to the high cost of treatment have a significant impact on the patient's physical, psychological, and social functions, resulting in a decrease in the quality of life of uveitis sufferers. Accurate assessment of patients' quality of life is helpful to guild treatment, enhance compliance and improve patients' overall quality of life. This article reviews the current progress on the quality of life assessment scales and psychological assessment tools to evaluate overall quality of life in patients with uveitis, thereby to provide reference and theoretical basis for selecting and developing the quality of life assessment tools for uveitis patients.

Disease-specific assessment of Vision Impairment in Low Luminance in age-related macular degeneration - a MACUSTAR study report.

BACKGROUND/AIMS: To further validate the Vision Impairment in Low Luminance (VILL) questionnaire, which captures visual functioning and vision-related quality of life (VRQoL) under low luminance, low-contrast conditions relevant to age-related macular degeneration (AMD). METHODS: The VILL was translated from German into English (UK), Danish, Dutch, French, Italian and Portuguese. Rasch analysis was used to assess psychometric characteristics of 716 participants (65% female, mean age 72±7 years, 82% intermediate AMD) from the baseline visit of the MACUSTAR study. In a subset of participants (n=301), test-retest reliability (intraclass correlation coefficient (ICC) and coefficient of repeatability (CoR)) and construct validity were assessed. RESULTS: Four items were removed from the VILL with 37 items due to misfit. The resulting Vision Impairment in Low Luminance with 33 items (VILL-33) has three subscales with no disordered thresholds and no misfitting items. No differential item functioning and no multidimensionality were observed. Person reliability and person separation index were 0.91 and 3.27 for the Vision Impairment in Low Luminance Reading Subscale (VILL-R), 0.87 and 2.58 for the Vision Impairment in Low Luminance Mobility Subscale (VILL-M), and 0.78 and 1.90 for the Vision Impairment in Low Luminance Emotional Subscale (VILL-E). ICC and CoR were 0.92 and 1.9 for VILL-R, 0.93 and 1.8 for VILL-M and 0.82 and 5.0 for VILL-E. Reported VRQoL decreased with advanced AMD stage (p<0.0001) and was lower in the intermediate AMD group than in the no AMD group (p≤0.0053). CONCLUSION: The VILL is a psychometrically sound patient-reported outcome instrument, and the results further support its reliability and validity across all AMD stages. We recommend the shortened version of the questionnaire with three subscales (VILL-33) for future use. TRIAL REGISTRATION NUMBER: NCT03349801.

Color diversity judgments in peripheral vision: Evidence against "cost-free" representations.

Is visual perception "rich" or "sparse?" One finding supporting the "rich" hypothesis shows that a specific visual summary representation, color diversity, is represented "cost-free" outside focally-attended regions in dual-task paradigms [1]. Here, we investigated whether this "cost-free" phenomenon for color diversity perception extends to peripheral vision. After replicating previous findings and verifying that color diversity is represented "cost-free" in central vision, we performed two experiments: in our first experiment, we extended the paradigm to peripheral vision and found that in minimally-attended regions of space, color diversity perception was impaired. In a second and final experiment, we added confidence judgments to our task, and found that participants maintained high levels of metacognitive awareness of impaired performance in minimally-attended visual areas in the periphery. These findings provide evidence that color perception may be partially attention-dependent in peripheral vision, and challenge previous views on both sides of the rich vs. sparse debate.

Optical Assessment and Expected Visual Quality of Four Extended Range of Vision Intraocular Lenses.

PURPOSE: To assess the optical performance of four extended range of vision (ERV) intraocular lenses (IOLs) and predict the visual quality of the average pseudophakic patient. METHODS: Four ERV IOLs (LuxSmart, Bausch & Lomb; Vivity, Alcon Laboratories, Inc; Tecnis Eyhance, Johnson & Johnson Vision; and Isopure, PhysIOL) were inserted in an on-bench model eye. Their performance was assessed using through-focus modulation transfer function (MTF)-based metrics, through-focus point spread function, and halo analysis for three pupils (2.0, 3.0, and 4.5 mm). The expected visual acuity and the range of vision was estimated from the through-focus area under the MTF curve. A monofocal IOL (Tecnis ZCB00; Johnson & Johnson Vision) was included as reference. RESULTS: The Tecnis ZCB00 showed the highest image quality at far for all pupil conditions, closely followed by the Tecnis Eyhance. The LuxSmart and Vivity performed similarly in the intermediate range (-1.00 to -2.00 diopters [D]) with a 3.0-mm pupil and showed better performance than the other ERV IOLs for that range. All ERV lenses presented pupil dependent performance. All lenses reached normal expected visual acuity (0.0 logMAR) at far distance. The Tecnis ZCB00, Tecnis Eyhance, and Isopure decreased their expected visual acuity with defocus (0.1 logMAR at 66 cm) faster than the LuxSmart and Vivity (0.0 logMAR at 66 cm). The LuxSmart and Vivity produced greater halos than the Tecnis ZCB00, but they showed little change with larger pupils. The Isopure lens showed a pupil-dependent halo. CONCLUSIONS: The expected visual acuity decreased with the object distance differently, depending on the ERV design. The Vivity and LuxSmart lenses showed an expanded imaging capability (⩾ 0.50 D) with respect to a monofocal lens that may benefit intermediate vision. The Tecnis Eyhance and Isopure lenses showed more modest extensions that mainly rely on pupil constriction. [J Refract Surg. 2022;38(11):688-697.].

No-Reference Quality Assessment of Stereoscopic Video Based on Temporal Adaptive Model for Improved Visual Communication.

An objective stereo video quality assessment (SVQA) strives to be consistent with human visual perception while ensuring a low time and labor cost of evaluation. The temporal-spatial characteristics of video make the data processing volume of quality evaluation surge, making an SVQA more challenging. Aiming at the effect of distortion on the stereoscopic temporal domain, a stereo video quality assessment method based on the temporal-spatial relation is proposed in this paper. Specifically, a temporal adaptive model (TAM) for a video is established to describe the space-time domain of the video from both local and global levels. This model can be easily embedded into any 2D CNN backbone network. Compared with the improved model based on 3D CNN, this model has obvious advantages in operating efficiency. Experimental results on NAMA3DS1-COSPAD1 database, WaterlooIVC 3D Video Phase I database, QI-SVQA database and SIAT depth quality database show that the model has excellent performance.

Assessment of the Performance of a Portable, Low-Cost and Open-Source Device for Luminance Mapping through a DIY Approach for Massive Application from a Human-Centred Perspective.

Ubiquitous computing has enabled the proliferation of low-cost solutions for capturing information about the user's environment or biometric parameters. In this sense, the do-it-yourself (DIY) approach to build new low-cost systems or verify the correspondence of low-cost systems compared to professional devices allows the spread of application possibilities. Following this trend, the authors aim to present a complete DIY and replicable procedure to evaluate the performance of a low-cost video luminance meter consisting of a Raspberry Pi and a camera module. The method initially consists of designing and developing a LED panel and a light cube that serves as reference illuminance sources. The luminance distribution along the two reference light sources is determined using a Konica Minolta luminance meter. With this approach, it is possible to identify an area for each light source with an almost equal luminance value. By applying a frame that covers part of the panel and shows only the area with nearly homogeneous luminance values and applying the two systems in a dark space in front of the low-cost video luminance meter mounted on a professional reference camera photometer LMK mobile air, it is possible to check the discrepancy in luminance values between the low-cost and professional systems when pointing different homogeneous light sources. In doing so, we primarily consider the peripheral shading effect, better known as the vignetting effect. We then differentiate the correction factor S of the Radiance Pcomb function to better match the luminance values of the low-cost system to the professional device. We also introduce an algorithm to differentiate the S factor depending on the light source. In general, the DIY calibration process described in the paper is time-consuming. However, the subsequent applications in various real-life scenarios allow us to verify the satisfactory performance of the low-cost system in terms of luminance mapping and glare evaluation compared to a professional device.

Rich Structural Index for Stereoscopic Image Quality Assessment.

The human visual system (HVS), affected by viewing distance when perceiving the stereo image information, is of great significance to study of stereoscopic image quality assessment. Many methods of stereoscopic image quality assessment do not have comprehensive consideration for human visual perception characteristics. In accordance with this, we propose a Rich Structural Index (RSI) for Stereoscopic Image objective Quality Assessment (SIQA) method based on multi-scale perception characteristics. To begin with, we put the stereo pair into the image pyramid based on Contrast Sensitivity Function (CSF) to obtain sensitive images of different resolution. Then, we obtain local Luminance and Structural Index (LSI) in a locally adaptive manner on gradient maps which consider the luminance masking and contrast masking. At the same time we use Singular Value Decomposition (SVD) to obtain the Sharpness and Intrinsic Structural Index (SISI) to effectively capture the changes introduced in the image (due to distortion). Meanwhile, considering the disparity edge structures, we use gradient cross-mapping algorithm to obtain Depth Texture Structural Index (DTSI). After that, we apply the standard deviation method for the above results to obtain contrast index of reference and distortion components. Finally, for the loss caused by the randomness of the parameters, we use Support Vector Machine Regression based on Genetic Algorithm (GA-SVR) training to obtain the final quality score. We conducted a comprehensive evaluation with state-of-the-art methods on four open databases. The experimental results show that the proposed method has stable performance and strong competitive advantage.

Measure of Early Vision Use: development of a new assessment tool for children with cerebral palsy.

PURPOSE: To report the development of an assessment tool to describe "how vision is used" for children with cerebral palsy. METHOD: Measurement development consisted of three steps: (i) an online survey to explore the relevance and comprehensiveness of visual behaviours identified in a previous conceptualisation study; (ii) construction of items and a rating scale for the new measure; and (iii) cognitive interviews to explore comprehensibility and refine the measure in preparation for field testing. Survey respondents were 130 parents of children with cerebral palsy, eight adults with cerebral palsy, and 108 clinicians (n = 246). Nine parents participated in the interviews. RESULTS: The new tool, the Measure of Early Vision Use, is a 14-item descriptive measure of typical performance of visual behaviours observable in everyday activities, as rated by parent/caregiver observation. Each item is rated on a 4-point ordinal scale. CONCLUSIONS: This new measure is conceptually grounded within the Activity level domain of the International Classification of Functioning, Disability and Health as a measure of a single visual ability construct. The target population is children with cerebral palsy, and using parent report the Measure of Early Vision Use describes both strengths and limitations in using vision. This study addressed the selection of items and response options for the new scale, and provides evidence to support content relevance, comprehensiveness and comprehensibility from key stakeholders. Further research will explore psychometric properties and clinical utility.Implications for rehabilitationThe ability to use vision in daily activities is relevant to the development and learning of all children, so the availability of a method for describing visual abilities has potential for diverse research and clinical purposes.The Measure of Early Vision Use is a parent-report tool that provides a criterion-referenced method for quantifying and describing how children use vision in typical daily activities to support intervention planning.Clinicians and parents wishing to measure vision use in children with cerebral palsy can be confident about the rigorous methods used to develop this tool, including consultation with key stakeholders.

Clinical validation of a novel web-application for remote assessment of distance visual acuity.

BACKGROUND/OBJECTIVES: Ophthalmic disorders cause 8% of hospital clinic attendances, the highest of any specialty. The fundamental need for a distance visual acuity (VA) measurement constrains remote consultation. A web-application, DigiVis, facilitates self-assessment of VA using two internet-connected devices. This prospective validation study aimed to establish its accuracy, reliability, usability and acceptability. SUBJECTS/METHODS: In total, 120 patients aged 5-87 years (median = 27) self-tested their vision twice using DigiVis in addition to their standard clinical assessment. Eyes with VA worse than +0.80 logMAR were excluded. Accuracy and test-retest (TRT) variability were compared using Bland-Altman analysis and intraclass correlation coefficients (ICC). Patient feedback was analysed. RESULTS: Bias between VA tests was insignificant at -0.001 (95% CI -0.017 to 0.015) logMAR. The upper limit of agreement (LOA) was 0.173 (95% CI 0.146 to 0.201) and the lower LOA -0.175 (95% CI -0.202 to -0.147) logMAR. The ICC was 0.818 (95% CI 0.748 to 0.869). DigiVis TRT mean bias was similarly insignificant, at 0.001 (95% CI -0.011 to 0.013) logMAR, the upper LOA was 0.124 (95% CI 0.103 to 0.144) and the lower LOA -0.121 (95% CI -0.142 to -0.101) logMAR. The ICC was 0.922 (95% CI 0.887 to 0.946). 95% of subjects were willing to use DigiVis to monitor vision at home. CONCLUSIONS: Self-tested distance VA using DigiVis is accurate, reliable and well accepted by patients. The app has potential to facilitate home monitoring, triage and remote consultation but widescale implementation will require integration with NHS databases and secure patient data storage.

Machine Learning Method for Functional Assessment of Retinal Models.

Challenges in the field of retinal prostheses motivate the development of retinal models to accurately simulate Retinal Ganglion Cells (RGCs) responses. The goal of retinal prostheses is to enable blind individuals to solve complex, reallife visual tasks. In this paper, we introduce the functional assessment (FA) of retinal models, which describes the concept of evaluating the performance of retinal models on visual understanding tasks. We present a machine learning method for FA: we feed traditional machine learning classifiers with RGC responses generated by retinal models, to solve object and digit recognition tasks (CIFAR-10, MNIST, Fashion MNIST, Imagenette). We examined critical FA aspects, including how the performance of FA depends on the task, how to optimally feed RGC responses to the classifiers and how the number of output neurons correlates with the model's accuracy. To increase the number of output neurons, we manipulated input images - by splitting and then feeding them to the retinal model and we found that image splitting does not significantly improve the model's accuracy. We also show that differences in the structure of datasets result in largely divergent performance of the retinal model (MNIST and Fashion MNIST exceeded 80% accuracy, while CIFAR-10 and Imagenette achieved ∼40%). Furthermore, retinal models which perform better in standard evaluation, i.e. more accurately predict RGC response, perform better in FA as well. However, unlike standard evaluation, FA results can be straightforwardly interpreted in the context of comparing the quality of visual perception.