Validation of a web-based distance visual acuity test.

PURPOSE:To validate the Democritus Digital Acuity and Reading Test (DDART) as a distance VA (dVA) test against a series of prevalent conventional distance vision charts. SETTING:Ophthalmology Department, University Hospital of Alexandroupolis, Alexandroupolis, Greece; Ophthalmology Department, AHEPA University Hospital, Thessaloniki, Greece; and Ophthalmica Institute of Ophthalmology & Microsurgery, Thessaloniki, Greece. DESIGN:Prospective multicenter validation study. METHODS:The distance best spectacle-corrected visual acuity (dBSCVA) was compared in normal (NVG) and low (LVG) vision participants against 4 prevalent conventional distance vision charts (ETDRS, Snellen, Landolt C, and Tumbling E) by a predefined 2.5-symbol noninferiority margin and intraclass correlation coefficients (ICCs). DDART's test-retest (TRT) reliability was assessed with ICCs. RESULTS:534 participants (471 and 63 with normal and low vision, respectively) were included in the study. The mean difference between dBSCVA measured with DDART and conventional charts ranged between -0.84 and +0.85 symbols, without exceeding the 2.5-symbol noninferiority margin. ICCs indicated an excellent level of agreement for all patient groups (from 0.848 to 0.985). TRT reliability indicated differences below 1 symbol both for the NVG and LVG, with ICCs ranging between 0.912 and 0.964 for the 4 DDARTs. CONCLUSIONS:DDART was a valid web-based dVA test that provided reliable measurements in clinical and telemedical settings, both for normal and low vision patients.