Abstract
Abstract: :
Background: Tests for binocular function and stereopsis are widely used by pediatric ophthalmologists due to their child–friendly characteristics. However, the diagnostic value of random–dot stereotests for amblyopia screening has recently been called into question. Purpose: to evaluate the effectiveness of 3 tests of binocular function and stereopsis for the use of preschool screening for amblyopia and strabismus. Methods: 665 children aged 3,5 to 4,5 years were screened in their kindergartens for amblyopia and strabismus. 88 of them also had a complete ophthalmologic examination. Stereopsis was examined using the TNO test and the Lang–II test. Binocular function was assessed using the Bagolini test. Referral criteria were negative test results and poor cooperation. Visual acuity was tested using the H–test, a modification of the Swedish Kolt–test. Amblyopia was diagnosed in cases of an interocular difference in acuity of 2 lines or more in a cooperative child or a acuity of <20/40 in the ophthalmologic office. All children had an orthoptic examination. All children in whom the presence or absence of amblyopia (n=581) or strabismus (n=657) could be definitely determined were included in this study. Results: Testability was high in this age group (98,0 % for Lang, 97,6 % for TNO and 88,4 % for Bagolini). The rates of unremarkable test results were 94,4, 94,0 and 83,9%. All 3 tests showed a low sensitivity for amblyopia (29, 23, 21%) and a moderate sensitivity for strabismus (62, 65, 62%). Specificity was high (88–98%). 34 (6) of the 52 (26) children with amblyopia (strabismus) were not detected by any of the 3 tests. Conclusion: The Lang test showed the best effectiveness for the detection of amblyopia and the TNO test for strabismus among the 3 examined tests. Their advantage is the high testability at preschool age. However, neither of the 3 tests can be recommended for preschool screening for amblyopia and strabismus when used alone. The screening tests would miss too many children requiring treatment. Their use in combination with visual acuity testing for amblyopia screening is discussed. The study is supported by the Bertelsmann foundation.
Keywords: amblyopia • binocular vision/stereopsis • strabismus: diagnosis and detection