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Breed associated defects in the ability to focus light in canine eyes


Melissa Kubai and others, University of Wisconsin


Ametropia is a condition in which light from a distant object is not focused accurately on the retina. It is a result of inadequate or excessive refractive power in the components of the optical pathway or because of abnormalities in the shape of the globe. In myopia, light is focused in front of the retina and in hyperopia, it is focused behind.

The authors examined eyes from 1,440 dogs from 90 different breeds using streak retinoscopy. Rottweilers, collies, miniature schnauzers and toy poodles were breeds in which the mean refractive state was myopic while in the Australian sheepdog, Alaskan malamute and bouvier des flandres the mean refractive state was hyperopic. The degree of myopia increased with increasing age across all breeds.

These results suggest that any dog that will be expected to perform tasks requiring high visual function should be tested before the animal begins intensive training.

American Journal of Veterinary Research 69 (7): 946-951.



Abstract reproduced by kind permission of Veterinary Practice magazine