PREVALENCE OF FOVEAL LESIONS IN TYPE-1 AND TYPE-2 USHERS SYNDROME

Purpose: To evaluate possible differences in the prevalence of clinica lly detectable foveal lesions between patients with type I and type 2 Usher's syndrome. Methods: Records of 48 patients with type 1 and 98 p atients with type 2 Usher's syndrome were retrospectively evaluated fo r the presence of a foveal lesion. The age, gender, and racial distrib ution of patients were similar in the two subtypes. Two investigators reviewed fundus photographs from all patients and, when available, flu orescein angiograms. Results: In the 48 patients with type I Usher's s yndrome, 30 (62%) showed a clinically apparent atrophic-or cystic-appe aring foveal lesion, whereas in the 98 patients with type 2 Usher's sy ndrome, 33 (34%) had either an atrophic-or a cystic-appearing foveal l esion. Logistic regression analysis showed that the probability of exh ibiting a foveal lesion in both type 1 and type 2 Usher's syndrome inc reases with age and that patients with type 1 Usher's syndrome are mor e likely to have a foveal lesion than are patients with type 2 Usher's syndrome. Conclusions: Patients with type 1 Usher's syndrome show a g reater probability of having either an atrophic or cystic-appearing fo veal lesion than do patients with type 2 Usher's syndrome. This higher prevalence of foveal lesions is consistent with a previous observatio n that the severity of visual acuity impairment with age is greater fo r patients with type 1 than type 2 Usher's syndrome. These data are us eful in counseling such patients as to their prognosis for central vis ual function.