Primary lens luxation in Norwich terriers

Primary lens luxation (PLL) is an eye disease where the supporting ligaments holding the lens of the eye are weak, which can allow the lens to detach, causing painful glaucoma and eventual blindness. PLL has been reported in more than 30 breeds, with most of the breeds being terriers. It is a late-onset disease, typically presenting between 4 and 8 years of age. A DNA test is available and breeders and owners can test to determine their dog's PLL status (normal, carrier, affected).

PLL has been found in Norwich terriers. The PLL DNA test identifies the simple recessive mutation causing PLL in Norwich terriers.

A PLL-affected dog (two copies of the PLL mutation) has an almost 100 percent chance of getting PLL. A PLL-carrier (one copy of the PLL mutation) has an estimated chance of 5 percent of getting PLL. PLL-carriers are recommended to have annual eye exams by a veterinary ophthalmologist. No Norwich PLL-carrier has been reported to get PLL.

As of Dec 2017, OFA reports that 187 Norwich terriers have been DNA tested for PLL, with 94 percent being normal, 5.5 percent carriers, and 0.5 percent affected.


An ADAMTS17 Splice Donor Site Mutation in Dogs with Primary Lens Luxation, Farias et al., IOVS, Sep 2010.

ADAMTS17 mutation associated with primary lens luxation is widespread among breeds, Gould et al., Veterinary Ophthalmology, 2011.

Last updated 20181209.