Use of the Arden grating test for screening.

One hundred and forty patients were referred for a clinical evaluation of their eyes, having produced high scores on screening by the Arden grating test (AGT). In these patients 66% of the eyes were found to be normal, 31% abnormal, and 3% indeterminate on clinical examination. Suitable criteria for referral for clinical examination were determined and the recommended scores are: (a) A total AGT score of greater than or equal to 80; (b) One or more plates scoring greater than or equal to 17; (c) A difference between the two eyes of greater than or equal to 13. With these criteria at least 95% of the abnormal eyes will be detected. As a screening test the AGT is equal to the Snellen distance visual acuity test at separating the normal group from the abnormal group, and on the recommended criteria the AGT gives a better ratio of false positives to false negatives.