Remote Vision Testing: Validation Of A Simple Home-Printable Vision Screening Test for Telemedicine

Abstract

Objectives: to develop and validate a simple paper vision test (the Home Acuity Test or HAT) for ophthalmology telemedicine appointments, which can be used by people who are digitally excluded. Design: Bland Altman analysis of the HAT chart, compared to the last measured visual acuity on a standard clinical test. Setting: Routine outpatient ophthalmology telemedicine clinics in a tertiary centre. Participants: 50 control subjects with no eye disease and 100 consecutive adult ophthalmology outpatients from strabismus and low vision telemedicine clinics. Participants were excluded if they reported subjective changes in their vision. Main outcome measures: For control participants, test/retest variability of the HAT and agreement with standard logMAR visual acuity measurement. For ophthalmology outpatients, agreement with the last recorded clinic visual acuity and with ICD11 visual impairment category. Results: For control participants, HAT test/retest variability was -0.012 logMAR (95% CI: -0.25 to 0.11 logMAR). Agreement with standard vision charts was -0.14 logMAR, with a 95% confidence interval of -0.39 to +0.12 logMAR (figure 3). For ophthalmology outpatients, agreement in visual acuity was -0.10 logMAR (one line on a conventional logMAR sight chart), with the HAT indicating poorer vision than the previous clinic test. The 95% confidence interval for difference was -0.44 to +0.24 logMAR. Agreement in visual impairment category was good for patients (Cohen's K test, K = 0.77 (95% CI, 0.74 to 0.81), and control participants (Cohen's K test, K = 0.88 (95% CI, 0.88 to 0.88). Conclusions The HAT can be used to measure vision by telephone for a wide range of ophthalmology outpatients with diverse conditions, including those who are severely visually impaired. Test/retest variability is low and agreement in visual impairment category is good.

Lockdown low vision assessment: an audit of 500 telephone‐based modified low vision consultations

“…Prior to the telephone assessment, patients were sent a large print appointment letter stating the purpose of the proposed call with a given appointment time. They were also sent a home acuity test (http://www.homeacuitytest.org) 9 with a 150 cm length of string to measure the chart viewing distance, Blu‐tack (http://www.bostik.com) to stick the charts to a wall and a near low vision test booklet.…”

“…Distance vision was assessed using the home acuity test (http://www.homeacuitytest.org) 9 which consists of two A4 sheets with crowded Sloan letters sized 1.30 to 0.10 logMAR. Patients were asked to read each chart monocularly wearing their habitual distance correction.…”

Remote visual impairment teaching clinics during COVID‐19 at a university optometry school

“…The supervising optometrist then took over and filled in any gaps. Following history, habitual distance visual acuity was measured using the validated Home Acuity test, 7 which had been printed out and posted to the patients in advance with a 1.5 m string. Patients were instructed to place the charts on a wall and use the string to stand at the correct distance from the chart.…”