Purpose: Because of controversial results in previous reports, we wished to further evaluate stereoacuity development in children with normal binocular vision, and to investigate the reliability of stereoscopic tests for screening for abnormal binocular vision and amblyopia.
Materials and methods: In a prospective study, 115 children, age 3 to 6 1/2 years, were first tested on the TNO and Titmus Stereotests, after which they received a more complete eye examination to determine the presence of ocular and vision abnormalities. Only specific quantitative stereotest results were tabulated for the development study.
Results: Binocular vision anomalies were detected by stereotesting in 3 of the 115 children. Testability was better on the TNO than the Titmus Stereotest. Using only the quantitative stereotest results, when segregated by age groups, there was a "statistically significant" change (improvement with age) on the TNO Test (p=.0001)(x2); whereas there was no such improvement found on the Titmus Stereotest Circles, p=.045, 0.72.
Conclusions: The TNO Test is reliable for screening for binocular vision anomalies and amblyopia. Also, normal stereopsis and stereoacuity acuity improves "significantly" between age 4 and 5 1/2 years, and reaches adult-like level at 5 1/2 years on this test.