Lens luxation in terriers

Primary lens luxation is an inherited weakness of the fibres that hold the lens in place. A single mutation in the ADAMTS17 gene accounts for it in many breeds: it was first identified in the Miniature Bull Terrier, Jack Russell Terrier and Lancashire Heeler and is present in at least 14 more, most of them terriers, along with the Chinese Crested and the Australian Cattle Dog¹. Dogs with two copies usually luxate a lens in middle age; one copy carries a lower risk.

A luxated lens is an emergency because it can block the drainage of the eye and cause glaucoma within hours, with a painful, red, cloudy eye². In a terrier of middle age or older, any sudden change in one eye, squinting, tearing, a blue or cloudy look, or a visible edge of the lens, needs a same-day appointment. A DNA test exists for the mutation and tells you whether to expect it.

This is general information, not a diagnosis. Your vet knows your dog.

Sources

1. ADAMTS17 mutation associated with primary lens luxation is widespread among breeds (Gould D et al.). Veterinary Ophthalmology 14(6):378-384, 2011 (peer reviewed). Accessed 2026-09-22.
2. Glaucoma in Animals. Merck Veterinary Manual. Accessed 2026-09-22.