Validity Of A Picture Visual Acuity Test.

Picture visual acuity tests are available for most standard vision examination projection charts. These pictures are used with pre-literate patients, mostly the pediatric population. These pictures have been assigned values in Snellen notation, i.e. 20/30, 20/40, etc. This study was designed to determine how well these assigned values correspond to Snellen acuity measurements. Data was obtained from 59 volunteers (however, n for statistical analysis was much lower due to ceiling and basement effects of the picture chart). Acuity was measured unaided using both the Snellen and picture charts. The order of the testing was randomized by both eye and test chart. Each eye served, as it's own control. A correlation was found between the values obtained on the picture acuity chart and the Snellen chart that was significant (r=. 922, t=7.77E-07, two-tailed). However, in 92.7% of the eyes tested, acuity was measured as worse using the picture charts than on the Snellen chart. An average of 0.166±0.108 SO.