Primary glaucoma in dogs: protecting the other eye
8-year-old American Cocker Spaniel with primary angle-closure glaucoma in the right eye, already blind. The left eye is visual with an intraocular pressure of 17 mmHg.
What do you recommend for the left eye?
chevron_right Show answer and explanation
A. Nothing while the pressure is normal, because primary glaucoma is unilateral
Primary glaucoma is a bilateral disease: the other eye's angle is equally abnormal and, without prophylaxis, about half develop glaucoma within months.
B. Prophylactic latanoprost twice daily for life
It is not the usual prophylaxis: its effect in a normotensive eye is limited and it causes miosis and some chronic inflammation. It is reserved for lowering pressure once raised.
C. Gonioscopy to assess the angle, prophylactic topical treatment (beta-blocker or carbonic anhydrase inhibitor) and regular pressure checks
Correct. Gonioscopy confirms pectinate ligament dysplasia or a narrow angle, and prophylactic treatment substantially delays the onset of glaucoma in the fellow eye. Teach the owner the warning signs.
D. Prophylactic atropine to keep the pupil dilated
It is the opposite of what is indicated: mydriasis narrows the angle and can trigger a glaucoma crisis.
lightbulb Key takeaway
Primary angle-closure glaucoma mainly affects American Cocker Spaniels, Basset Hounds, Siberian Huskies, Shibas, Chow Chows, Shar Peis and Samoyeds. When one eye is affected, the other is at risk: prophylaxis from day one and urgent visit if it becomes red, cloudy or the pupil dilates.
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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.