[Congenital cataract in a cynomolgus monkey].

The anterior part of the eye was examined with 1,531 newborn cynomolgus monkeys (Macaca fascicularis). A male (about 0.07%) of those newborns was noticed to have white opacities in his both eyes (Fig. 1). This finding was diagnosed to be bilateral congenital cataract by observing with a slit-lamp biomicroscope. Partial resorption of the white opaque part occurred one week after birth in the right eye (Fig. 2) and three weeks after birth in the left eye (Fig. 3). As a result of the resorption, observation of the ocular fundus by an ophthalmoscope became possible at two and seven weeks of age in the right and left eyes, respectively (Figs. 6 and 7), even though the ophthalmoscopic figures were not complete. White opacities occupied again nearly the whole area of the lens at 10 months of age in the left eye (Fig. 4) and at 14 months of age in the right eye (Fig. 5). Breeding studies are needed to determine if this case has any genetic background.