Automated determination of distance visual acuity: towards teleophthalmology services.
OBJECTIVE
The aim of this study was to evaluate the visual acuity scores of a computer-based visual function testing (CVFT) system. The automated chart uses logMAR notation (logarithm of the minimum angle of resolution) and randomised tilting E as optotype. The test was conducted using a laptop computer.


METHODS
This prospective, clinic-based, test validation study was based on a model of repeatability in two observations. The right eyes of a total of 104 participants were randomly tested with both CVFT and the manual, gold standard Early Treatment of Diabetic Retinopathy Study (ETDRS) chart.


RESULTS
The mean difference between CVFT and ETDRS was -0.01+/-0.11 (SD) logMAR units. The Spearman Rank correlation coefficient (r) between the absolute difference and the average was 0.35. The average time for testing one eye was 54.7+/-11.89 seconds. The mean difference between two consecutive, repeated CVFT tests in the same eye was 0.02+/-0.07 logMAR units (paired t-test p=0.046).


CONCLUSIONS
A novel, automated visual acuity testing application is reported. This automated system should be a useful tool for mass screening of visual impairment in rural and remote regions with its ease of use and shorter testing time.
Kumar
Sajeesh
S
Centre of Excellence in e-Medicine, Lions Eye Institute, University of Western Australia, Nedlands WA, Australia. sajeesh@cyllene.uwa.edu.au
Bulsara
Max
M
Yogesan
Kanagasingam
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004215:Distance Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009885:Ophthalmology / Q000379:methods*; D011446:Prospective Studies; D019114:Remote Consultation; D015203:Reproducibility of Results; D012424:Rural Population; D014786:Vision Disorders / Q000175:diagnosis; D014787:Vision Tests / Q000592:standards*; D014792:Visual Acuity / Q000502:physiology*