[Effective vision screening can decrease the rate of amblyopia].

The quality of screening for testing visual disorders is unsatisfactory. Diagnosis and therapy are generally too late to exploit the advantage therapy can give during the sensitive period of visual acuity. About 10% of the adult population show decreased visual acuity (below 0.8). These persons have a more or less distinct amblyopia. Commonly used visual acuity tests do not allow the crowding phenomenon to be measured, although it is an easily measurable amblyopia characteristic. The most frequently used visual acuity test by German health authorities (R 5/R 11 test with plate No. 120) shows 48% false-negative results. We introduced the H test for preschool children. For school children and adults we developed the C test. To detect amblyopia precisely we designed both tests so that the crowding phenomenon could be measured. Both tests were validated in more than 700 subjects. All persons received an extensive ophthalmological checkup, which was used as the reference for normality. The H test is based on the matching principle and works with musical feedback. The test can be used from the age of 3 years onward. Therefore, the advantage of early therapy can be fully exploited. The H test has a 3% percentage false-negative rate. The C test is based on the Landolt ring. The visual acuity charts are presented as a book (40 cm distance) for measuring near visual acuity and (5 m) for measuring distance visual acuity. The C test has less than 5% false-negative results. Both tests can help in different age groups to diagnose amblyopic cases.(ABSTRACT TRUNCATED AT 250 WORDS)