A cataract is a condition in which the lens becomes cloudy or totally opaque. When this occurs, incoming light is impeded, if not totally prevented, from passing through to the retina. In some cases, the opaque area of the lens is tiny and without consequence. In others, the entire lens may be opaque, in which case total blindness will result.
Some feline cataracts develop as the result of an animal’s inability to metabolize proteins and other body chemicals, or they may be a byproduct of diabetes or hypertension. Older cats often get them as a natural consequence of the aging process. Rarely, cataracts may develop following exposure to certain drugs, toxic substances, radiation or electric shock.
Early medical treatment for high blood pressure or diabetes will sometimes be effective in slowing the rate of the progression. In other cases, surgery may be required. In the procedure, the ophthalmologist uses an operating microscope to make small incisions first in the cornea and then in the lens capsule before inserting an instrument that uses high-frequency sound to disintegrate and remove the affected lens. An artificial lens is then inserted and the incision is sutured. The delicate surgery — which typically takes about an hour — is successful in most cats that have qualified as good candidates for implantation of the artificial lens.