Retinopathy in Greyhound dogs: Prevalence, fundoscopic, and histopathological findings.

Objectives: To determine the prevalence of retinal lesions and describe the fundoscopic findings of retinopathy in Greyhound dogs in the Manawatu/Whanganui region of New Zealand. To examine possible associations between sex, age, and racing variables with retinopathy in the study population. To describe retinal histologic findings in seven Greyhounds with retinopathy in New Zealand.

Methods: Two hundred Greyhound dogs from the Manawatu/Whanganui region of New Zealand underwent fundoscopy and fundic photography to identify and score the degree of retinopathy. Associations between retinopathy and age, sex, as well as racing variables, were examined. Histologic examination of the retina was undertaken on the eyes of seven Greyhounds from the Manawatu and Canterbury regions previously diagnosed with retinopathy by fundoscopy.

Results: Fifty dogs (25.1%) were identified with retinopathy of varying degrees of severity. In at least one eye, 7.5% of dogs had mild retinopathy, 11.6% moderate retinopathy, and 6.0% severe retinopathy. Males were more likely to be affected in both eyes and with moderate or severe grades, than females. Increasing age was not associated with increased prevalence of retinopathy, nor increased grade of severity. Retinal histology identified multifocal retinal detachment in 5 of the 7 cases examined and other common lesions included choroidal necrosis and outer to full-thickness retinal atrophy in the absence of significant inflammation.

Conclusions: Retinopathy is prevalent in Greyhounds in the Manawatu/Whanganui region of New Zealand, but more research is required to elucidate the etiopathogenesis. Consideration should be made to include mandatory eye health examination in racing Greyhound dogs.