AIMS OR PURPOSE: Screening for amblyopia at earliest age is important for early treatment and better prognosis. This study aimed at evaluating the validity of uncorrected distant and near visual acuity and random dot stereopsis for screening amblyopia. METHODS; In Eastern Taiwan, population-based screen tests were performed for children at age from 3 to 6 years. The tests included uncorrected distant and near visions and random dot stereopsis (300 s) test. The screen performers were registered nurses of local public health service posts. The golden standards of the tests were the results of examination by the ophthalmologists.
Results: Including Hans and aboriginal Taiwanese, 5232 children were included. Screened by distance visual acuity with different cutoffs and near visual acuity, 10.3, 30.3 and 8.2% children were abnormal. Screened by random dot, only 2% children were abnormal. By a senior ophthalmologist, 115 amblyopic children were diagnosed amblyopic. The sensitivities of distance visual acuity with low/high cutoff and near visual acuity were 74.7/84.8 and 49.4%, whereas that of the NTU random dot stereogram was 20.5%. Simultaneous testing of either two of the three tests improved the sensitivity.
Conclusion: Screening for amblyopia by the local nurses using the visual acuity tests or random dot stereopsis test alone does not display a high sensitivity. Simultaneous testing of distant visual acuity and stereopsis test elevate the sensitivity and preserve the specificity.