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

Louise Allen, Arun James Thirunavukarasu, Simon Podgorski, Deborah Mullinger, Louise Allen, Arun James Thirunavukarasu, Simon Podgorski, Deborah Mullinger

Abstract

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.

Keywords: remote consultation; software validation; telemedicine; visual acuity.

Conflict of interest statement

Competing interests: LA is the inventor and developer of DigiVis and founding director of Cambridge Medical Innovations. An international patent application has been made by Cambridge Enterprise.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1
Figure 1
(A) Randomised optotype presentation on the distant device; the arrow indicates the letter to match. (B) The appearance of randomised letters on the handheld device, one of which matches the indicated letter on the distant test chart. The ‘not sure’ button registers as an incorrect attempt.
Figure 2
Figure 2
Bland-Altman plot comparing DigiVis visual acuity measurements with standard clinical testing to evaluate accuracy. The bias and 95% limits of agreement (dashed lines) are labelled and have 95% CIs (dotted lines) shaded. LOA, limits of agreement. logMAR, Logarithm of the Minimum Angle of Resolution.
Figure 3
Figure 3
Bland-Altman plot comparing repeated DigiVis measurements to evaluate test–retest agreement. The bias and 95% LOA (dashed lines) are labelled and have 95% CIs (dotted lines) shaded. LOA, limits of agreement. logMAR, Logarithm of the Minimum Angle of Resolution.

References

    1. BMA . Pressure points in the NHS.. Available:
    1. NHS . Online version of the NHS Long Term Plan: NHS.. Available:
    1. Steren BJ, Young B, Chow J. Visual acuity testing for telehealth using mobile applications. JAMA Ophthalmol 2021;139:344–7. 10.1001/jamaophthalmol.2020.6177
    1. Kawamoto K, Stanojcic N, Li J-PO, et al. . Visual acuity Apps for rapid integration in Teleconsultation services in all resource settings: a review. Asia Pac J Ophthalmol 2021;10:350–4. 10.1097/APO.0000000000000384
    1. Painter S, Ramm L, Wadlow L, et al. . Parental home vision testing of children during Covid-19 pandemic. Br Ir Orthopt J 2021;17:13. 10.22599/bioj.157
    1. Bastawrous A, Rono HK, Livingstone IAT, et al. . Development and validation of a smartphone-based visual acuity test (peek acuity) for clinical practice and community-based fieldwork. JAMA Ophthalmol 2015;133:930–7. 10.1001/jamaophthalmol.2015.1468
    1. Dawkins A, Bjerre A. Do the near computerised and non-computerised crowded Kay picture tests produce the same measure of visual acuity? British and Irish Orthoptic Journal 2018;13:22.
    1. García-Pérez MA. Properties of some variants of adaptive staircases with fixed step sizes. Spat Vis 2002;15:303–21. 10.1163/15685680260174056
    1. Koo TK, Li MY. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. J Chiropr Med 2016;15:155–63. 10.1016/j.jcm.2016.02.012
    1. Manny RE, Hussein M, Gwiazda J, et al. . Repeatability of ETDRS visual acuity in children. Invest Ophthalmol Vis Sci 2003;44:3294–300. 10.1167/iovs.02-1199
    1. Laidlaw DAH, Tailor V, Shah N, et al. . Validation of a computerised logMAR visual acuity measurement system (COMPlog): comparison with ETDRS and the electronic ETDRS testing algorithm in adults and amblyopic children. Br J Ophthalmol 2008;92:241–4. 10.1136/bjo.2007.121715
    1. Srinivasan K, Ramesh SV, Babu N, et al. . Efficacy of a remote based computerised visual acuity measurement. Br J Ophthalmol 2012;96:987–90. 10.1136/bjophthalmol-2012-301751
    1. Shah N, Laidlaw DAH, Rashid S, et al. . Validation of printed and computerised crowded Kay picture logMAR tests against gold standard ETDRS acuity test chart measurements in adult and amblyopic paediatric subjects. Eye 2012;26:593–600. 10.1038/eye.2011.333
    1. Thirunavukarasu AJ, Mullinger D, Rufus-Toye RM, et al. . Clinical validation of a novel web-application for remote assessment of distance visual acuity. Eye 2021. 10.1038/s41433-021-01760-2. [Epub ahead of print: 30 Aug 2021].
    1. NHS England . Digital inclusion in healthcare. Available:

Source: PubMed

Sponsors and Collaborators

Medical Conditions

Drug Interventions

3
Subscribe