Sudden Acquired Retinal Degeneration Syndrome (SARDS) in Dogs Explained

Sudden Acquired Retinal Degeneration Syndrome (SARDS) is a serious eye condition in dogs that causes rapid, irreversible blindness. Unlike many other eye conditions that develop gradually, SARDS is characterised by a sudden and complete loss of vision, typically occurring within days to weeks. This guide covers the causes, symptoms, diagnosis, and management of SARDS in dogs.

What Causes SARDS?

The exact cause of SARDS is not fully understood, despite extensive research. The condition involves the rapid degeneration and death of the photoreceptors in the retina (the rods and cones), which are the cells responsible for detecting light and converting it into neural signals. Various theories have been proposed, including immune-mediated mechanisms, hormonal influences, and toxic causes, but none has been definitively proven. SARDS occurs most commonly in middle-aged to older dogs, with females appearing to be more commonly affected than males, and some breeds seem predisposed, including Dachshunds, Pugs, Miniature Schnauzers, and Cocker Spaniels.

Signs and Symptoms of SARDS

The hallmark sign of SARDS is sudden onset of blindness. Owners typically report that their dog appeared to lose vision very rapidly — sometimes almost overnight. Signs include:

• Bumping into furniture and objects
• Reluctance to move in low light or unfamiliar environments
• Dilated pupils that do not constrict in response to light
• An absent or reduced menace response (the dog does not blink when a hand is moved rapidly towards the eye)

Many dogs with SARDS also show systemic signs including increased thirst and urination, increased appetite, and weight gain. These signs overlap with those of hyperadrenocorticism (Cushing’s disease), and the relationship between SARDS and hormonal disturbances is an area of ongoing research.

Diagnosis of SARDS

Diagnosis involves a thorough ophthalmological examination, including assessment of pupillary light reflexes and the menace response. The definitive diagnostic test for SARDS is electroretinography (ERG), which measures the electrical activity of the retina in response to light. In SARDS, the ERG is flat (extinguished), confirming that retinal function has been lost. This is important to distinguish SARDS from sudden blindness due to other causes such as retinal detachment or optic neuritis, which may be treatable.

Treatment and Management of SARDS

There is currently no proven effective treatment that can restore vision once SARDS has occurred. The blindness is permanent. Management focuses on helping the dog adapt to its new situation. Most dogs adapt remarkably well to blindness, particularly if they remain in familiar environments. Keeping furniture in fixed positions, using scent markers, and introducing verbal cues for hazards (such as stairs) can all help. The systemic signs may also require investigation and management in their own right.