VALIDATION AND CLINICAL APPLICATIONS OF DEMOCRITUS DIGITAL ACUITY READING TEST DDART

Primary objective of this study is the development and validation of the web-based Democritus Digital Acuity Reading Test – wDDART, which is based on the previously developed and validated Windows-based DDART.

The development of wDDART was carried out in the Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece, while the validation was conducted in the Department of Ophthalmology, University Hospital of Alexandroupolis, Alexandoupolis, Greece.

This is a prospective, comparative clinic-based trial. wDDART displays sentences with text sizes from 1.3 to -0.5 logMAR for different patient-screen distances and automatically calculates: reading acuity (RA), maximum reading speed (MRS), critical print size (CPS) and reading accessibility index (ACC). It provides advanced text calibration features and monitors examination distance using computer vision techniques. For the validation, normal and low vision patients responded to wDDART and the Windows-based version DDART on the same day, at 40cm distance. wDDART-derived reading parameters were compared with the corresponding ones from DDART. Test-retest reliability of wDDART was evaluated in a 15-day time-window.

One hundred patients (normal vision group - NVG: 70 patients; 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 ranged between 0.715 and 0.895 for MRS and CPS.

To our knowledge, wDDART is the first validated ophthalmological reading assessment tool that is available as a web application with many novel features. Study outcomes suggest comparable validity to the DDART reading tool and high test-retest reliability, making it sufficient for clinical and research settings for the evaluation of reading acuity and reading performance in normal and low vision patients. The potential uses of wDDART as a web-based diagnostic tool are numerous, including support for screening initiatives and application to remote health facilities.