Objective: To determine the incidence, etiology, and concurrent ophthalmic findings in small breed dogs that presented with cataracts.
Animal studied: Five hundred and sixty-one small breed dogs (942 eyes) were presented to the Veterinary Medical Teaching Hospital of Seoul National University between July 2002 and December 2007 with cataract.
Procedure: The medical records of small breed dogs with cataract were reviewed. The reason for presentation, cataract duration, bilaterality, breed, gender, age, vision, etiology, stage of cataract development, concurrent ophthalmic findings, IOP, ocular ultrasonography findings, and scotopic electroretinography (ERG) findings were investigated.
Results: The most frequently presented breeds were the Miniature/Toy Poodle (n = 112, 20.0%), Yorkshire Terrier (n = 110, 19.6%), and Shih Tzu (n = 95, 16.9%). The Miniature/Toy Poodle showed a significantly higher odds ratio for cataract formation (2.6). The proportion of female cataract patients was significantly higher than that of male cataract patients in the overall population (P < 0.05). The Miniature/Toy Poodles had significantly higher numbers of females affected with cataract (P < 0.01). The mean age for cataract formation was 8.3 +/- 3.9 years. The mean age at onset in the Miniature/Toy Poodle and Yorkshire Terrier was significantly higher, whereas that in the Miniature Schnauzer group was significantly lower (P < 0.0001). Clinical signs related to lens induced uveitis had a tendency to increase with cataract progression (P < 0.05). There were no significant differences in the b-wave amplitude for mixed rod cone response by stage (P = 0.137).
Conclusions: Small breed dogs with cataracts had characteristics with regard to age of onset and gender distribution, depending on the breed.