Lens-induced uveitis in dogs: 151 cases (1985-1990)

Summary During a 5-year period, phacolytic uveitis was diagnosed in 202 eyes of 151 dogs admitted to the veterinary teaching hospital. The diagnosis of phacolytic uveitis was based on the finding of a cataractous lens and anterior uveitis, unassociated with other identifiable causes of uveal inflammation. The most commonly affected breeds were the Toy and Miniature Poodle (35%) and the American Cocker Spaniel (19%). The mean age was 7.0 years for all breeds, 5.1 years for the Cocker Spaniel, and 9.0 years for the Poodle breeds. Evidence of cataract resorption was visible in 72% of the eyes. Fifty-one dogs were affected bilaterally and 100 dogs unilaterally. The mean interval between recognition of the cataract and the onset of lens-induced uveitis (liu) was 17 months; mean times of 25 and 11 months were seen in the Poodle breeds and American Cocker Spaniel, respectively. The mean age of dogs requiring > 1 revisit before the inflammation had subsided was 5.5 years. Complications, referable to the uveitis, were seen in 14% of eyes, the most important of which were glaucoma (16 eyes) and phthisis bulbi (9 eyes). Lens extraction surgery was done on 50 liu-affected eyes, and on 35 normal eyes in liu-affected animals. The 2- and 6-month success rates for liu-affected eyes were 78 and 39%, respectively, and for normal eyes in liu-affected animals were 85 and 71%, respectively. On the basis of findings, we suggest that liu develops sooner after the onset of cataract formation in young dogs, and implies that their response to medical treatment is worse when compared with that in older dogs. It is probable that higher concentrations of lenticular α-crystallin protein, along with faster cataract resorption in the lens of young dogs, account for this decreased responsiveness to anti-inflammatory treatment, because T-cell tolerance to α-crystallin is more easily terminated than to other lens proteins. The observation that normal eyes of liu-affected dogs retained a good prognosis following lens extraction surgery suggests that local, rather than systemic, immune factors are of primary importance in the pathogenesis of canine liu.