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.

Novel web application for self-assessment of distance visual acuity to support remote consultation: a real-world validation study in children.

OBJECTIVE: The difficulty in accurately assessing distance visual acuity (VA) at home limits the usefulness of remote consultation in ophthalmology. A novel web application, DigiVis, enables automated VA self-assessment using standard digital devices. This study aims to compare its accuracy and reliability in children with clinical assessment by a healthcare professional. METHODS AND ANALYSIS: Children aged 4-10 years were recruited from a paediatric ophthalmology service. Those with VA worse than +0.8 logMAR (Logarithm of the Minimum Angle of Resolution) or with cognitive impairment were excluded. Bland-Altman statistics were used to analyse both the accuracy and repeatability of VA self-testing. User feedback was collected by questionnaire. RESULTS: The left eyes of 89 children (median 7 years) were tested. VA self-testing showed a mean bias of 0.023 logMAR, with a limit of agreement (LOA) of ±0.195 logMAR and an intraclass correlation coefficient (ICC) of 0.816. A second test was possible in 80 (90%) children. Test-retest comparison showed a mean bias of 0.010, with an LOA of ±0.179 logMAR, an ICC of 0.815 and a repeatability coefficient of 0.012. 96% of children rated the test as good or excellent, as did 99% of their parents. CONCLUSION: Digital self-testing gave comparable distance VA assessments with clinical testing in children and was well accepted. Since DigiVis self-testing can be performed under direct supervision using medical video consultation software, it may be a useful tool to enable a proportion of paediatric eye clinic attendances to be moved online, reducing time off school and releasing face-to-face clinical capacity for those who need it.