Visual acuity with habitual correction on an ETDRS chart vs protocol refraction on an electronic ETDRS chart in diabetic macular edema

Abstract

Purpose : To compare technician-measured visual acuity (VA) in clinical practice using Early Treatment Diabetic Retinopathy Study (ETDRS) charts with VA following protocol refraction using electronic ETDRS (E-ETDRS) charts in diabetic macular edema (DME) patients.

Methods : Prospective case series in which participants (n=32) with DME had visual acuity measured first using habitual correction and an ETDRS chart, followed by E-ETDRS VA test letter score on an E-ETDRS device using habitual correction, followed by best-corrected visual acuity (BCVA) on an E-ETDRS device after protocol refraction.

Results : Median ETDRS presenting VA of 20/40 and median E-ETDRS presenting VA letter score of 70 (20/40) improved after protocol refraction to a median E-ETDRS BCVA letter score of 75 (20/32). Median difference between E-ETDRS BCVA and ETDRS presenting VA was 0.0 (0 letters; 25^th quartile -0.1 [5 letters], 75^thquartile 0.1 [5 letters]) with 34 eyes (73.9%) changing ≥5 letters. These changes resulted in 8/46 (17.4%; 95% CI: 6.4%-28.3%) eyes switching from E-ETDRS BCVA 20/40 or better to 20/50 or worse, or vice versa.

Conclusions : While VA changed ≥5 letters in a majority of eyes when comparing E-ETDRS BCVA with ETDRS presenting VA, these findings suggest few cases likely change categorically from 20/40 or better to 20/50 or worse, or vice versa. When managing DME, ETDRS presenting VA with habitual correction may be acceptable despite the interaction of baseline VA among different anti-VEGF agents for DME when categorized in a trial using protocol refracted E-ETDRS VA as 20/32 to 20/40 vs 20/50 or worse.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.