Disorder - Rod-cone degeneration

Organ Systems Involved
Nervous/sensory

Alternative disorders described within LIDA

Central progressive retinal atrophy; Feline retinal atrophy / degeneration; Pigmentary retinal degeneration (Type II ); Retinal pigment epithelial dystrophy; Retinitis pigmentosa

Alternative Names
Early onset retinopathy / Early onset retinal degeneration; Late onset retinopathy / Late onset retinal degenerationPhotoreceptor dysplasia; Progressive rod-cone degeneration; Rod-cone dysplasia

Presenting Signs

The retina is the light sensitive part of the inner surface of the eye, located at the back of the eyeball. It contains light receptors called rods and cones, which receive light as it enters the eye, and transform it into image-forming signals that are transmitted to the brain. Rod cells detect shape and motion, and function in dim light. Cone cells detect colour and definition, and function in bright light.

Cats are affected by two types of rod-cone degeneration: late-onset and early-onset degeneration. Cats affected by late-onset rod-cone degeneration experience progressive deterioration of the rods and then of cones from the age of five months onwards. In the early stages from 1.5 to two years of age, cats may show increased light reflection from the retinal surface (tapetum) when a light is shone directly into the eye. The rods and cones deteriorate from the edges to the central cells. Degeneration progresses to blindness in the late stage of the disease around three to four years after the first signs are noticed.

Cats with early-onset degeneration are born with visual impairment and may have involuntary fast horizontal movements of the eyes (nystagmus). At four weeks of age the pupils may appear wider than usual, and they progress to blindness at around 12-16 months. In early-onset degeneration rods and cones are equally affected from the edges to the central cells.

Cats at Risk

Early onset: kittens from birth
Late onset: cats over five months of age

Breeds Affected
Abyssinian


Treatment

None currently available

PubMed References
Rod-cone degeneration

Contributor
Jen Shepherd