Progressive retinal atrophy: night blindness in dogs
5-year-old Labrador Retriever that for months has been bumping into things when going out at night and hesitating in dim places; during the day he seems to see well. Pupils somewhat dilated with slow reflexes. On fundoscopy, mild tapetal hyperreflectivity and slightly thin retinal vessels in both eyes. Normal blood pressure.
Which statement is correct?
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A. It is consistent with progressive retinal atrophy; ERG confirms the loss of photoreceptor function and no treatment halts its progression
Correct. Rods are affected first (night blindness) and then cones, leading to complete blindness over months to years. ERG is reduced even with minimal fundus changes, and in Labradors the prcd test confirms the hereditary form.
B. It is sudden acquired retinal degeneration syndrome (SARDS) and should be treated with immunosuppressants
SARDS causes sudden blindness (days to weeks), by day and night, with an initially normal fundus. Months of night blindness with degenerative changes fit progressive atrophy.
C. Antioxidant supplements halt progression if started early
There is no solid evidence that any supplement halts progressive retinal atrophy in dogs. An owner may use them, but the prognosis does not change.
D. It is hypertensive retinopathy and amlodipine should be started
Blood pressure is normal, and hypertensive retinopathy produces haemorrhages, oedema or detachment, not a slow symmetrical degeneration with night blindness.
lightbulb Key takeaway
Signs of progressive retinal atrophy: night blindness, dilated pupils, tapetal hyperreflectivity, vascular attenuation and disc pallor; it is bilateral and symmetrical and often accompanied by secondary cataract. Dogs adapt well to gradual blindness; control lies in DNA testing of breeding animals.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.