Comparison of visual acuity levels in pediatric patients with amblyopia using Wright figures, Allen optotypes, and Snellen letters.

PURPOSE

To compare and correlate the clinical performance of Wright figures in visual acuity assessments of pediatric patients with amblyopia to those obtained through Allen cards and Snellen letters.

SUBJECTS AND METHODS

Best-corrected visual acuity of 26 amblyopic children were measured with the Wright figures(c), Snellen letters, and isolated Allen optotypes, respectively. Amblyopia was defined as two lines of visual acuity difference or a visual acuity level of 20/30 or lower as determined by Snellen chart. The results were evaluated for statistical intergroup differences using the Wilks' Lambda multivariate analysis of variance and for correlation using the Pearson correlation coefficient test.

RESULTS

The mean age of the subjects was 8.27 +/- 2.46 years (range: 5 to 15 years). The mean logMAR values for the Wright figures(c), Snellen letters, and Allen optotypes were 0.40 +/- 0.20, 0.47 +/- 0.23, and 0.29 +/- 0.28, respectively. When compared with Snellen letters, the Wright figures correlated to a higher degree ( r = 0.46, P < 0.001) than Allen optotypes ( r = 0.67, P < 0.001). With a visual acuity of 20/40 or worse on Snellen letter testing, the sensitivity of Wright figures(c) and Allen cards in diagnosing amblyopic eyes was 87.0 and 56.5%, respectively ( P = 0.016).

CONCLUSIONS

Wright figures, designed primarily to evaluate the vision in the preliterate pediatric population, correlate more closely to Snellen letters and have a higher rate of correctly identifying amblyopia than isolated Allen optotypes in pediatric patients.