Opacity of the lens of the eye or its capsule or both. Cataract may result from injuries to the eye, exposure to great heat or radiation, or inherited factors. Rare in cattle and swine, common in dogs. Treatment consists of surgical removal of the lens (lens extraction or cataract extraction). May affect the entire lens or be localized, e.g. posterior polar cataract.
- acquired c. — any non-congenital cataract; usually the result of trauma, systemic disease or another eye disorder.
- after-c. — 1. any membrane of the pupillary area after extraction or absorption of the lens. — 2. secondary cataract (below).
- capsular c. — one consisting of an opacity of the capsule of the lens.
- complicated c. — a cataract occurring secondarily to other intraocular disease.
- congenital c. — present at birth; often not progressive. See also white eye calf syndrome.
- cortical c. — an opacity in the cortex of the lens. The common form of cataract in dogs; inherited in many breeds, often in association with progressive retinal atrophy.
- developmental c. — one that occurs at any age before the animal becomes an adult.
- diabetic c. — one associated with diabetes mellitus.
- electric c. — one caused by electrical current as in electrocution.
- embryonal c. — one caused by prenatal influences.
- focal ring c. — a perinuclear opacity with normal lens fibers surrounding it. Usually the result of an in utero or neonatal insult to the lens.
- galactosemic c. — see galactosemia.
- hyaloid c. — a focal opacity at the point where the hyaloid artery meets the posterior lens capsule. See also mittendorf's dot.
- hypermature c. — one in which the lens has begun to liquefy.
- immature c. — incomplete opacity.
- incipient c. — a very early stage of development with no impairment of vision.
- inherited c. — occurs in a number of breeds of cattle, often in combination with other abnormalities of the eye. Affected calves are usually normal in other respects and can be reared if the inconvenience of their blindness can be overcome. Also occurs in dogs, often with late onset and in association with other inherited ocular defects such as progressive retinal atrophy.
- intumescent c. — a mature cataract that has become swollen.
- juvenile c. — one developing in very young animals, for example dogs less than 6 months of age.
- lenticular c. — opacity of the lens not affecting the capsule.
- mature c. — one in which the lens is completely opaque.
- morgagnian c. — liquefaction, except the nucleus which drops to the bottom of the lens, and shrinkage of the capsule.
- nuclear c. — one involving the nucleus of the lens; the common form of congenital cataracts.
- nuclear Y c. — a form of congenital cataract in which small opacities outline the Y suture of the nucleus.
- nutritional c. — see galactosemia.
- radiation c. — one caused by radiation, as in radiotherapy.
- reduplication c. — a capsular opacity covered by another layer of epithelium.
- secondary c. — 1. one that forms after most of the lens has been removed. — 2. complicated cataract.
- senile c. — occurs in the aged of all species, preceded by nuclear sclerosis.
- subcapsular c. — may be anterior or posterior. Inherited in several breeds of dogs.
- toxic c. — one caused by exposure to a toxic substance.
- traumatic c. — one caused by trauma.
