Primary lens luxation causes acute pain and blindness in terrier breeds. Prompt surgical intervention preserves vision and relieves welfare-critical intraocular pressure.
Primary lens luxation presents as a welfare emergency when the lens moves anteriorly into the front chamber of the eye. The resulting secondary glaucoma — raised intraocular pressure — is intensely painful. Dogs with acute glaucoma show blepharospasm (squinting), photophobia, a visibly red and cloudy eye, and signs of pain including head rubbing, lethargy, and behavioral changes. The pain of acute glaucoma is severe and constitutes a welfare crisis requiring emergency treatment.
Time is critical: the retina begins suffering irreversible ischemic damage within hours of significantly elevated IOP. Emergency lens extraction, when performed promptly, can restore normal drainage, relieve pain, and preserve vision. Every hour of delay reduces the probability of visual outcome. Owners of predisposed breeds should be educated to recognize signs and seek emergency ophthalmology care immediately.
A DNA test for the PLL mutation is available and should be used in all breeding programs involving susceptible Terrier breeds. Breeding only clear or carrier-to-clear pairings prevents affected dogs from being born — the most welfare-protective intervention of all.