Remote assessment of visual acuity during video consultations

Abstract

Purpose: To assess the reliability and repeatability of visual acuity (VA) measurement obtained remotely via electronic devices using the Optonet Vision Unit (OVU), a web‐based digital eye care software used in eye care practitioner's consultations.Methods: A total of 78 adult participants (20–54 years of age) were recruited, 36 from Glasgow Caledonian University (Scotland, UK) and 42 from the University of Murcia (Spain). Each participant underwent a monocular VA test and retest (TRT, right eye) using three different VA charts, two of them performed in the practitioner's consultation: the Early Treatment Diabetic Retinopathy Study (ETDRS) chart as the gold‐standard VA test and the OVU computerized VA chart (Optonet Ltd©, UK) designed according to the ETDRS format; and one remote VA measurement obtained in another room using OVU. Prior to the remote VA measurement, each participant set up the video‐consultation version of the OVU software on a screen through directions provided by the examiner from another room via a Zoom call (Zoom Video Communications©, Inc., CA, USA). Small adjustments could be made by the examiner using the information that the electronic device used by the participant transmitted to the online software to which it was connected. Participants were asked to stand about 4 meters from the screen and instructed to read the letters presented. The order of VA acquisition was randomized for each participant. VA scores were recorded in logMAR, and data were analysed with SPSS. The duration of the video consultation was timed from the moment the Zoom call link was sent to the participant until the VA measurement was completed.Results: The mean ± standard deviation (SD) of VA measured was −0.006 ± 0.14 logMAR with the ETDRS chart, −0.07 ± 0.15 logMAR with OVU and –0.05 ± 0.16 logMAR with remote OVU. TRT variability (range comprising 95% differences) showed a good agreement in ETDRS chart (mean difference ± 0.0077 logMAR, 95% CI: −0.014 to 0.06); OVU (mean difference ± 0.0028 logMAR, 95% CI: −0.012 to 0.10); and remote OVU (mean difference ± 0.0024 logMAR, 95% CI: −0.012 to 0.08). The duration of the remote VA assessment was 6.68 ± 2.21 min.Conclusion: This study demonstrates the potential of OVU charts for clinical and teleconsultation uses, which may be useful for VA measurement in remotely based patients.