The formation of new fibers in the lens of the cat’s eye continues throughout life. As new fibers are formed the older ones are compressed and pushed toward the center of the lens. This results in a continually increasing density of the lens. The lens also loses water as it ages, another factor contributing to increased density.
This process is called nuclear sclerosis and should be recognized as a normal part of the aging of the cat’s eyes. It results in a bluish or grayish-white haze in the part of the lens that can be seen through the pupil. It does not normally interfere with vision and does not need treatment. This condition is often erroneously referred to as cataracts (lens opacities that interfere with light transmission to the retina). In truth, senile cataracts, which usually appear very white and dense and which interfere with vision, occur much less commonly.
If your cat does develop cataracts as an aged (or sometimes young) animal and loss of vision occurs, there are surgical procedures that can be used to remove the opacity and restore vision. Surgery is best performed by a veterinary specialist because cataracts are relatively uncommon, and the best results are obtained only by those individuals who perform the operations most frequently. Most cats seem to adjust completely to a gradual loss of vision should surgery be unavailable or contraindicated.