Disorder - Retinal degeneration type II

Organ Systems Involved
Nervous/sensory

Alternative disorders described within LIDA

Cataracts; Congenital night blindness; Glaucoma; Hemeralopia; Maculopathy; Primary retinal degeneration; Progressive retinal atrophy; Rod-cone dysplasia / degeneration; Rod dysplasia

Alternative Names
Central progressive retinal atrophy; Central progressive retinal degeneration; Feline retinal atrophy / degeneration; Generalised progressive retinal atrophy; Photoreceptor dysplasia; Pigmentary retinal degeneration (Type II ); Progressive rod-cone degeneration; Retinal pigment epithelial dystrophy; Retinitis pigmentosa; 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 receptors that receive the light as it enters the eye, and transform it into image-forming signals that are transmitted to the brain. In retinal degeneration, the nerve receptor cells on the retina deteriorate, and blood flow to the retina is reduced. This eventually leads to blindness.

Retinal degeneration disorders identified in cats occur in both eyes and may be classified as early-onset or late-onset. In late-onset retinal degeneration, cats are born with normal vision, but at five to eight months of age experience initial loss of central vision. As the disease progresses, the pupil gradually appears wider and does not contract if light is shone into the eye. Affected cats may be unable to fix their eyes on objects and may have poor night vision. When shining a light directly into the eyes of an affected cat, the cat may not react to the light ('dazzle'), and you might see an increase in reflection from the reflective surface of the retina (tapetum). Affected cats may see moving but not stationary objects. Complete degeneration of the retina may occur at three to four years, causing complete blindness. Cataracts may also develop later in the disease.

In the early-onset form seen in Persians breeds, cats are born with visual impairment, dilated pupils and sometimes involuntary fast horizontal eye movements (nystagmus). This form is rapidly progressing and blindness occurs by 16-17 weeks of age.

Cats at Risk

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

Breeds Affected
Abyssinian
Ocicat
Persian
Siamese
Somali


Treatment

None currently available

Contributor
Jen Shepherd