Indocyanine green angiography findings with Collie eye anomaly in Hokkaido dogs
概要
Collie eye anomaly (CEA) is an inherited, congenital ocular disorder caused by a defective mesodermal differentiation in the posterior segment of the eye. Major ocular finding of CEA is abnormalities of choroidal vessels, that is choroidal hypoplasia. Indocyanine green angiography (IA) is one of the useful ocular examination to observe choroidal vessels in both human and dogs. The purpose of this study was to evaluate IA with CEA in Hokkaido dogs, which is one of the traditional Japanese breed and natural monument in Japan. Ten Hokkaido dogs that had been carried out genetic tests in advance were included in this study. Dogs included in this study had ophthalmic examination, such as menace response, dazzle reflex, direct and indirect pupillary light reflex, slit-lamp biomicroscopy, simple funduscopy, and IA. According to the result of genetic tests, they were classified as 8 affected and 2 carrier dogs. Simple funduscopy revealed choroidal hypoplasia bilaterally and temporal or dorsotemporal area to the optic disc in all affected dogs. With IA, we could observe the abnormalities of choroidal vessels not only at the area coincided with choroidal hypoplasia with simple funduscopy but also at the area detected normal with simple funduscopy in affected dogs. No abnormalities on fundus were observed with both simple funduscopy and IA in all carrier dogs. In conclusion, it was revealed that choroidal hypoplasia in CEA Hokkaido dogs was existed also in the area that could not be observed with simple funduscopy.