Causes and Management of Macular and Retinal Degeneration

Eye HealthQ&AMeongsiljang Veterinary Advisory Board

Retinal degeneration is a progressive eye disease that gradually leads to vision loss. We’ve outlined the causes, symptoms, early detection methods, and key care points from a pet owner’s perspective.

What is Retinal Degeneration?

A veterinarian examining a puppy’s eyes with a slit lamp.

Retinal degeneration is a progressive eye disease in which the light-sensitive cells of the retina—the tissue at the back of the eye that detects light—gradually break down, leading to a slow loss of vision. Early detection is key. If your pet frequently bumps into objects in dim light or walks along walls for more than two to three weeks, schedule an examination with a veterinary ophthalmologist right away. Because retinal degeneration is typically painless and progresses slowly, owners often notice signs only after the condition has advanced significantly.

What Causes It?

Retinal degeneration is broadly categorized into hereditary and acquired forms. Hereditary cases are often referred to as Progressive Retinal Atrophy (PRA) and are particularly common in certain breeds. Acquired degeneration can result from age-related changes, sudden acquired retinal degeneration syndrome (SARDS), nutritional deficiencies (such as taurine deficiency in cats), adverse drug reactions, or other ocular conditions like glaucoma or retinal detachment. According to veterinary ophthalmology textbooks, the condition typically progresses simultaneously in both eyes.

Comparison of Main Types of Retinal Degeneration

Item	Progressive Retinal Atrophy	Sudden Acquired Retinal Degeneration (SARDS)	Age-related retinal degeneration
Rate of onset	Months to years	Days to weeks	Years
Main target	Specific breeds (hereditary)	Dogs (regardless of breed)	Older animals in general
Vision loss	Gradual complete blindness	Sudden complete blindness	Gradual decline
Cause	Hereditary	Unknown	Aging
Treatment	None (management-focused)	None	Supportive management

Actual differentiation is performed with fundus examination and electroretinography (ERG).

Suspect It If You Notice These Behaviors

In the early stages of retinal degeneration, behavioral changes are often the first sign. - Night blindness: Your pet may bump into things more frequently in the evening or in dimly lit rooms. - Dilated pupils: The pupils may remain widely dilated even in bright light. - Increased eye shine: The inside of the eye may appear unusually bright when exposed to a flash of light. - Walking along walls or furniture: Due to impaired spatial awareness, your pet may follow boundaries to navigate. - Anxiety and reduced activity: Your pet may be reluctant to move in unfamiliar environments. If your pet fails to respond even when only one eye is covered, it may indicate that vision loss has already progressed.

An elderly dog walking carefully along the wall in a dark room

When Immediate Veterinary Ophthalmic Care Is Needed

If your pet suddenly loses vision in both eyes within a few days, if both pupils are widely dilated and unresponsive to light, or if the eyes appear cloudy with redness and pain, emergency veterinary ophthalmic care is required. In particular, sudden acquired retinal degenerative syndrome (SARDS) can lead to complete blindness within days, making prompt diagnosis critical. If glaucoma or retinal detachment is present, even remaining vision may be lost.

How Is It Diagnosed?

Retinal degeneration is often missed during routine health checkups, so a specialized ophthalmic examination is necessary. There are three primary diagnostic tests: - Fundus examination: After dilating the pupil, the veterinarian directly inspects the retina. - Electroretinography (ERG): This test measures the electrical responses of photoreceptor cells to assess retinal function. - Ocular ultrasound: This helps rule out other causes, such as retinal detachment or tumors. For breeds suspected of having hereditary retinal degeneration, genetic testing can provide early confirmation.

A veterinarian performing a fundoscopic examination on a cat

Are There Treatment and Management Options?

Unfortunately, there is currently no treatment that can restore already damaged photoreceptor cells. However, we can attempt management strategies aimed at slowing disease progression and preserving remaining vision. Antioxidant supplements are sometimes used to reduce oxidative stress in the retina and slow progression, but it is crucial to understand that they do not halt the disease process or prevent blindness. In cats, dietary management with adequate taurine is important in the early stages when taurine deficiency is suspected as the cause. Taurine is an essential amino acid for cats, and prolonged deficiency can lead to severe retinal damage; it is known that approximately 110 mg per kilogram of body weight per day is required to maintain normal retinal structure and function. Please remember, however, that taurine supplementation has no effect on restoring vision in cases of advanced retinal degeneration or established blindness. Cataracts often develop over time, so if concurrent cataracts or glaucoma are present, it is important to actively treat each condition to prevent secondary damage. Always consult your veterinarian before deciding to use any supplements.

How to Help Your Pet at Home as Vision Declines

Even with declining vision, your pet can adapt well using their sense of smell and hearing. The most important thing is for you to adjust the home environment. - Keep furniture in place: Maintain familiar pathways - Protect sharp corners: Add cushion covers to sharp edges - Use verbal cues: Call their name or make sounds to help them locate you - Stick to the same walking routes: Use familiar paths to help them remember the space - Mark stair entrances: Use non-slip mats or scents to identify stairs If your pet seems anxious, place a blanket with your scent nearby to help them feel secure.

A caregiver tending to an elderly, blind dog in a safe indoor environment

Pay Extra Attention to These Breeds

Hereditary retinal degeneration is commonly reported in many dog breeds, including Miniature Schnauzers, Labrador Retrievers, Golden Retrievers, Irish Setters, Dachshunds, and Collies, and the number of breeds known to be affected continues to grow. Some cat breeds can also develop hereditary retinal degeneration. The age of onset for hereditary retinal atrophy varies significantly depending on its form. Early-onset cases show symptoms as early as 6 weeks to 6 months of age, potentially leading to blindness by 1 to 5 years of age, while late-onset cases typically begin showing symptoms around 3 to 5 years of age, often resulting in complete blindness by 6 to 8 years. Therefore, for high-risk breeds, it is important to begin specialized ophthalmic examinations early in life, tailored to the breed and specific form of the disease, and genetic testing before breeding can help reduce the spread of the condition.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is retinal degeneration curable?

In current veterinary ophthalmology, there is no treatment to restore damaged visual cells, making a complete cure difficult. However, early detection combined with antioxidant management and treatment of any concurrent conditions can help slow the progression of the disease.

Can a blind pet still live a happy life?

Yes, most pets adapt quite well. Dogs and cats have highly developed senses of smell and hearing, so they can navigate and function comfortably in familiar environments even without sight. Your careful management of their surroundings is the most important support you can provide.

Do lutein and other supplements really work?

Products containing antioxidants are sometimes used to reduce oxidative stress in the retina and slow disease progression. However, it is important to remember that they cannot restore already damaged cells or prevent blindness. Please consult your veterinarian to determine whether these products are appropriate for your pet and to establish the correct dosage.

If my pet only has night blindness, should I take them to the vet right away?

Yes, night blindness is the most common early sign of retinal degeneration. Don’t dismiss it as simple aging; instead, have a fundus examination to confirm the cause. The earlier it’s detected, the longer your pet’s remaining vision can be preserved.

Can hereditary retinal degeneration be prevented?

While preventing this condition in individual dogs can be challenging, genetic testing before breeding can help reduce its transmission to the next generation. When adopting a dog of this breed, we recommend checking the parents' ophthalmic examination records.

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References

[1] Maggs DJ, Miller PE, Ofri R. Slatter's Fundamentals of Veterinary Ophthalmology, 6th Ed, Chapter 17: Retina

[2] Gelatt KN. Veterinary Ophthalmology, 6th Ed, Chapter: The Retinal Atrophies (RAs)

[3] Clinical Atlas of Canine and Feline Ophthalmic Disease, 2nd Ed, Chapter 135: The Retinal Atrophies

[4] Ettinger SJ, Feldman EC, Côté E. Textbook of Veterinary Internal Medicine, 8th Ed