Spontaneous ocular abnormalities in Crl:CD(SD) rats

Abstract

Ophthalmic examinations were conducted with accumulation of historical control data in Crl:CD(SD) rats from 2004 to 2007 and the spontaneous ocular abnormalities were analyzed. A total of 484 control rats from 22 toxicological studies were examined with slit lamp biomicroscopy and indirect ophthalmoscopy. The age of animals at examination ranged from 8 to 31 weeks and the number of control animals per study was 10 to 20 per sex.
There was a high incidence of ocular abnormalities in the cornea and lens with incidences of 47% and 31%, respectively. These abnormalities consisted of opacities. The corneal finding observed mostly was interpalpebral punctate opacity. The lens opacities were observed in the anterior subcapsular, anterior cortical, cortical nuclear junction, nuclear, posterior cortical and posterior capsular. Of the lens opacities, nuclear changes were observed with the highest incidence of 23% and the anterior cortical opacities were observed with the second highest incidence of 8%. The incidence of ocular abnormalities in the conjunctiva, iris, vitreous, retina and choroid were 2% and below. The incidence of corneal and lens opacities were very variable depending on the lot of rats and were not very related to age range examined.