Prevalence of foveal lesions in type 1 and type 2 Usher's syndrome
G. A. Fishman, R. J. Anderson, B. L. Lam and D. J. Derlacki
Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago College of Medicine, USA.
PURPOSE: To evaluate possible differences in the prevalence of clinically
detectable foveal lesions between patients with type 1 and type 2 Usher's
syndrome. METHODS: Records of 48 patients with type 1 and 98 patients with
type 2 Usher's syndrome were retrospectively evaluated for the presence of
a foveal lesion. The age, gender, and racial distribution of patients were
similar in the two subtypes. Two investigators reviewed fundus photographs
from all patients and, when available, fluorescein angiograms. RESULTS: In
the 48 patients with type 1 Usher's syndrome, 30 (62%) showed a clinically
apparent atrophic- or cystic-appearing foveal lesion, whereas in the 98
patients with type 2 Usher's syndrome, 33 (34%) had either an atrophic- or
a cystic-appearing foveal lesion. Logistic regression analysis showed that
the probability of exhibiting a foveal lesion in both type 1 and type 2
Usher's syndrome increases with age and that patients with type 1 Usher's
syndrome are more 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 greater probability of having either an atrophic- or
cystic-appearing foveal lesion than do patients with type 2 Usher's
syndrome. This higher prevalence of foveal lesions is consistent with a
previous observation that the severity of visual acuity impairment with age
is greater for patients with type 1 than type 2 Usher's syndrome. These
data are useful in counseling such patients as to their prognosis for
central visual function.
