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.

Development and Validation of a Web-Based Reading Test for Normal and Low Vision Patients

Purpose

To develop and validate a web-based reading test for normal and low vision patients.

Methods

This is a prospective, comparative trial. The web-based Democritus Digital Acuity Reading Test (wDDART) was developed. wDDART introduces a series of advanced characteristics (advanced text calibration, computer-vision-based estimation of patient’s distance, and automatic calculation of patient’s reading times) that facilitate the overall examination procedure. wDDART’s reading parameters [reading acuity (RA), maximum reading speed (MRS), critical print size (CPS) and reading accessibility index (ACC)] were compared to the corresponding ones of its conventional Windows-based reading test (DDART) in a sample of normal and low vision participants. wDDART’s test–retest reliability for all reading parameters was evaluated in a 15-day time-window.

Results

One hundred patients (normal vision group-NVG: 70; low vision group-LVG: 30 patients) responded to DDART and wDDART. Non-significant differences between the two reading tests were found for all parameters in NVG and LVG. Intraclass correlation coefficients (ICCs) between the two tests demonstrated good or excellent correlation for RA, MRS, ACC and moderate correlation for CPS. Test–retest reliability was excellent for RA and ACC, while ICCs were 0.715–0.895 for MRS and CPS.

Conclusion

The wDDART demonstrated sufficient validity and repeatability making it suitable for clinical and research settings.

Clinicaltrials.gov Identifier

NCT04618224.