SPONTANEOUS RETINAL CHANGES IN SPRAGUE-DAWLEY RATS

Routine ophthalmological examination of over 6,000 untreated Crl:CD(SD )BR rats up to 2 years old, used in toxicologic studies from 1989 to 1 992, has provided information on spontaneous retinal changes and their incidence with age. Focal linear retinopathy and coloboma were the mo st common findings; retinal hemorrhage, saccular aneurysm of the retin al vessels, retinal fold, absence of optic disk and retinal vasculariz ation, and myelination of optic nerve fibers were also observed, Such accumulated data in untreated animals are of prime necessity in assess ing possible drug- and chemical-induced effects on the eye after eithe r systemic or local exposure.