Comprehensive explanations of difficult pet health problems.

FIND A VETERINARY SPECIALIST

who can treat your pet in the best way possible.

Mi.

Sudden Acquired Retinal Degeneration (SARDS)

Dog - Eyes 624-386.jpg

Veterinary ophthalmologists have identified a condition of rapid onset blindness: Sudden Acquired Retinal Degeneration Syndrome (SARDS). Examination of tissue specimens from some patients has indicated that the retinas of these pets are totally destroyed and cannot regenerate. The related blindness occurs rapidly.

 

Introduction

Veterinary ophthalmologists have identified a condition of rapid onset blindness: Sudden Acquired Retinal Degeneration Syndrome (SARDS). Examination of tissue specimens from some patients has indicated that the retinas of these pets are totally destroyed and cannot regenerate. The related blindness occurs rapidly.

The degeneration is so rapid that vision loss can occur over the course of a few days to weeks. In addition to sudden vision loss, an owner may also notice that the pupils become dilated.

Whenever your pet is showing signs of a health issue your first step is to contact your primary care veterinarian. If it is indicated that your pet may suffer from SARDS or another serious condition, a veterinary specialist is available at an ExpertVet certified or affiliated hospital.

 

Signs and Symptoms

Though the cause of SARDS is currently unknown, the condition can be associated with an increase in thirst, urination, and weight gain in pets. These signs can resolve over time (weeks to months after the onset of blindness) although some dogs are affected longer. It usually occurs in pets that seem to be healthy; however, lab work will often reveal abnormalities such as elevated cholesterol, lipids (fat), or liver enzymes in the blood. The disease normally occurs in middle-aged to older female dogs, but males can also be affected. SARDS may occur in any breed including mixed-breed dogs; however, of the pure-bred dogs, Dachshunds and Schnauzers appear to be overrepresented.

 

Diagnosis

In a dog with SARDS, an examination by a veterinary ophthalmologist would reveal that the dog has normal eyes with no evidence of significant cataract development and no evidence of apparent retinal disease; however, the pet is blind. Correctly diagnosing the cause of a pet’s sudden blindness is important because if systemic disease or optic neuritis is causing the blindness, medication may restore vision. If a brain tumor is determined to be present, then radiation therapy may be necessary to save your pet's life.

Since the retina and ocular examination appears normal on initial evaluation with the exception of the dilated pupils, an electroretinogram (ERG) is an essential diagnostic test that can distinguish SARDS from other causes of blindness, such as central nervous system disorders of the optic nerve or brain. An ERG simply involves placing a specialized contact lens on the eye and flashing a series of lights. The dog may be sedated, but awake for this procedure. Each flash of light should stimulate the retina to produce a small electrical response that can be measured by a computer. The response is then compared to normal values.

If your pet has SARDS, the ERG will show an absence of retinal activity. If the retinal activity is normal, then the reason for vision loss may be within the brain or optic nerve. In such cases, additional diagnostic testing or consultation with a neurologist may be recommended to determine the cause of blindness.

 

Treatment and Prognosis

Unfortunately, research efforts have not revealed a definitive treatment to regain vision nor has a preventative treatment been identified. Some SARDS patients will have secondary uveitis or episcleritis and may need to be treated with anti-inflammatory ophthalmic mediations. This, however, is uncommon. 

Early test results in people with specific retinal diseases have suggested that some retinal disease might be improved by treating with trace minerals and/or vitamins. Zinc supplementation has become an important method of treatment in human patients with age-related retinal degeneration.

Vitamins A, E, and lutein have been identified as important components in canine retinal metabolism. In the near future, supplementation with trace minerals (zinc and others) and vitamins (A and E) may become recommended treatments for SARDS and other retinal degenerations (e.g., progressive retinal atrophy).

Because pets with SARDS have rapid vision loss, adjustment to their home environment takes several weeks. Dogs' strong sense of smell, memory, and hearing are important during their adaptive period.

Certainly there is a period of confusion and frustration, but most return to being relaxed and "normal" after this adjustment period. In time, patients can maintain a normal and healthy life. As well, SARDS does not cause discomfort or pain, making a patient’s adjustment to blindness easier and ensuring that a good quality of life can be maintained. In rare cases, a pet will become aggressive or have a significant personality change. The most important thing is to be patient. Your dog will memorize its surroundings and will get along well in familiar territory.

Precautions will need to be taken if the surroundings include a swimming pool or an open roadside as a non-seeing dog may fall into a pool or venture onto a road. Some pets may need a diet change as their activity level may decrease. If signs of low activity, weight gain, and increase in thirst or urination persist, further testing by your veterinarian or referral to a veterinary specialist may be recommended.

Recent Articles

Lymphangiectasia

A Different Rodenticide Toxicity

Cholangiohepatitis in Cats

Megacolon in Cats

Menu

ExpertVet