Progressive Retinal Atrophy (PRA) in Cats: Inherited Retinal Degeneration

Oct 18 • 10 min read

Your cat has started hesitating before jumping onto the sofa at night. She seems nervous walking into the darker room down the hall, something that never used to bother her. In bright light, you notice her eyes catching the light in a way they didn't before, and her pupils look a little more dilated than usual. Nothing about this looks painful, but something in her vision is clearly changing.

Progressive retinal atrophy (PRA) is an inherited condition in which the light-sensitive cells of the retina gradually deteriorate, eventually leading to blindness. It mainly affects Abyssinian and Persian cats, though any cat can be evaluated for it. PRA is not painful, there is currently no cure, and most cats adapt remarkably well to the gradual vision loss with a few thoughtful changes at home.

Key Takeaways

PRA is a group of inherited diseases that cause the retina's photoreceptor cells to deteriorate over time, eventually leading to blindness.
Abyssinian and Persian cats are currently the only breeds confirmed to develop PRA as an inherited condition.
Night blindness, dilated pupils, and eyes that seem unusually reflective in light are usually the earliest signs.
PRA is not painful, and there is currently no effective treatment or cure.
Diagnosis relies on an eye exam and, often, referral to a veterinary ophthalmologist for a specialized test called an electroretinogram (ERG).
Most cats with PRA adapt very well to vision loss, especially with a stable, predictable home environment.
What Is the Retina, and What Does PRA Do to It?

What Is the Retina, and What Does PRA Do to It?

Diagram showing the retina and photoreceptor cells inside a cat's eye

The retina is a light-sensitive layer of cells at the back of the eye. When light enters the eye, the lens focuses it onto the retina, where specialized cells called photoreceptors convert that light into electrical signals sent to the brain for processing. Cats have two main types of photoreceptors: rod cells, which handle vision in low light and detect movement, and cone cells, which handle color vision and don't work well in dim conditions. Cats' eyes contain far more rod cells than cone cells, which is part of why cats see so well in low light.

Atrophy means the partial or complete wasting away of a body part. Progressive retinal atrophy is the name for a group of degenerative diseases that affect these photoreceptor cells. Over time, the cells deteriorate, and vision gradually worsens until the affected cat becomes completely blind.

The Two Forms of PRA in Cats

There are two recognized forms of PRA in cats, and they behave quite differently:

Retinal dysplasia is an early-onset, inherited form usually diagnosed in kittens around two to three months of age. With this form, the photoreceptor cells develop abnormally from the start, and both rods and cones are typically affected together, leading to early blindness.

Progressive retinal atrophy (the late-onset form) develops in adult cats, typically between two and five years of age. Here, the retina's cells actually develop normally at first, but they degenerate over time. In most cases, the rod cells degenerate first, which is why night vision problems usually show up before daytime vision is affected. Eventually, the cone cells degenerate too, leading to complete blindness in both eyes.

Which Cat Breeds Are at Risk?

Currently, Abyssinian and Persian cats are the only breeds in which PRA has been confirmed to occur as an inherited condition. In Abyssinian cats, the early-onset retinal dysplasia form follows a dominant inheritance pattern, while the late-onset form is inherited in an autosomal recessive pattern, meaning an affected cat must inherit the defective gene from both parents. In Persian cats, a recessive inheritance pattern has been confirmed, though the specific gene responsible hasn't been identified yet.

Because PRA is heritable, a cat diagnosed with the condition should be removed from any breeding program, along with its parents and siblings, even if those relatives show no signs themselves. Since the typical pattern is recessive, unaffected parents and siblings are often carriers who inherited one copy of the defective gene alongside one normal copy. With careful, selective breeding, PRA could potentially be eliminated as a heritable condition over time.

Signs of PRA in Cats

Illustrated checklist of common progressive retinal atrophy signs in cats

PRA is not a painful condition, which means it's often not noticed in its earliest stages. The signs to watch for include:

Night blindness, often the very first sign noticed, showing up as nervousness at night or reluctance to enter dark rooms
Bumping into furniture or objects, especially in dim lighting
Eyes that appear unusually reflective when light shines on them
Pupils that are more dilated than normal
Gradual worsening of vision that affects both eyes equally
Eventually, difficulty navigating even in daylight as the disease progresses

If a cat with developing PRA rarely goes outdoors or into unfamiliar environments, the condition may go completely unnoticed until the cat is already fully blind, since cats compensate remarkably well using memory and their other senses in a familiar space.

How Is PRA Diagnosed?

Your vet may first suspect PRA based on a general eye exam that shows dilated pupils and sluggish pupillary light responses. In the earliest stages, though, it can be genuinely difficult to see any obvious changes to the retina itself. As the disease progresses, an eye exam using an ophthalmoscope can reveal changes to the optic nerve, changes in the retinal blood vessels, and increased reflectivity in a structure called the tapetum lucidum, the layer behind the retina responsible for that characteristic "eyeshine."

To confirm the diagnosis, or to rule out other causes of vision loss, your vet will likely recommend more specialized testing, most commonly an electroretinogram (ERG). This usually means a referral to a veterinary ophthalmologist. The ERG is sensitive enough to detect PRA even before a cat shows any obvious outward symptoms. For Abyssinian and Persian cats specifically, DNA testing is also available to identify the genes involved.

Could It Be Something Else?

Because PRA develops slowly and shares some signs with other causes of vision loss, your vet will want to rule out several other possibilities before confirming a PRA diagnosis:

Taurine deficiency. Cats require a specific amount of the amino acid taurine in their diet to prevent retinal degeneration. This is now rare in cats fed a proper commercial cat food, but it can occur in cats fed unbalanced homemade diets or dog food, since dog food isn't formulated with the taurine levels cats specifically need.
Cataracts, glaucoma, uveitis, and lens luxation. These conditions can also cause slowly progressive vision loss, but unlike PRA, they tend to be painful, so signs like squinting, redness, or a visibly cloudy eye point toward one of these instead.
Medication-related retinal damage. Sudden blindness in cats has been linked to overdoses of certain antibiotics, particularly enrofloxacin. This tends to happen quickly rather than gradually.

This is exactly why a vision change in your cat deserves a proper veterinary workup rather than an assumption, since some of these look-alike causes are treatable or even preventable.

Is There a Treatment for PRA?

There is currently no effective treatment available for inherited PRA in cats. Antioxidant supplements and vitamins have not been shown to have any measurable effect on slowing the disease, although they are not harmful and may offer some general support for eye health. If an underlying, separate condition such as cataracts or retinal detachment is identified as a contributing factor, treating that specific condition may help prevent further vision loss from that particular cause, but it won't reverse PRA itself.

"As PRA progresses, your cat's vision gradually worsens until she becomes completely blind. For the average family pet, blindness is not as significant as it would be in a human." — VCA Animal Hospitals, Progressive Retinal Atrophy in Cats

How Fast Does PRA Progress?

In most cases, cats experience a complete loss of vision over a period of one to two years. The pace can vary somewhat between individual cats and between the early-onset and late-onset forms, but the overall pattern is a steady, gradual decline rather than a sudden one, which gives most cats time to adapt naturally as their vision changes.

Helping Your Cat Adapt to Vision Loss

The encouraging part of a PRA diagnosis is that cats generally cope with blindness far better than people often expect. Blind cats rely more heavily on their other senses, especially smell, hearing, and whisker-guided navigation, and they move around a familiar home with impressive confidence. A few practical steps make a real difference:

Infographic showing tips for helping a cat adapt to vision loss from progressive retinal atrophy

Keep furniture, food and water bowls, litter trays, and beds in the same place, and avoid rearranging rooms unnecessarily
Consider confining your cat to a smaller, safe area at first if vision loss is progressing, then gradually expand access to the rest of the home once they're confident
Announce yourself with your voice before touching or picking up your cat, so you don't startle them
Keep stairs, balconies, and open water sources (like an open toilet lid) blocked off or supervised during the adjustment period
Maintain regular play and interaction, since a blind cat can still be just as playful and affectionate with the right cues

Because both eyes are affected together in PRA, and because the condition itself isn't painful, most cats go on to live full, comfortable lives once their home environment is set up to support them.

FAQ Section

Is progressive retinal atrophy painful for cats?
No. PRA is not a painful condition, which is actually part of why it can go unnoticed in its early stages. The main effect is a gradual, painless loss of vision rather than any discomfort in the eye itself.

Can progressive retinal atrophy be cured?
No, there is currently no effective treatment or cure for inherited PRA in cats. Antioxidant supplements have not shown a measurable effect on the disease's progression, though they aren't harmful. Management focuses on adapting the home environment to support a cat as vision declines.

Which cat breeds are prone to PRA?
Abyssinian and Persian cats are currently the only breeds confirmed to develop PRA as an inherited condition. Abyssinians can develop either the early-onset (retinal dysplasia) or late-onset form, while Persians are associated with a recessive inheritance pattern of the disease.

What is usually the first sign of PRA in a cat?
Night blindness is typically the earliest sign pet parents notice. This can look like nervousness at night, reluctance to enter dark rooms, or bumping into furniture in dim lighting, since the rod cells responsible for night vision tend to degenerate first.

How is PRA different from cataracts or other causes of blindness in cats?
PRA is a slow, painless degeneration of the retina's photoreceptor cells. Conditions like cataracts, glaucoma, and uveitis can also cause progressive vision loss, but they tend to be painful and often show visible changes like cloudiness or redness in the eye. A veterinary eye exam, and sometimes a specialized test called an electroretinogram, is needed to tell these apart.