Collie Eye Anomaly describes a, congenital, hereditary disease resulting from abnormal embryonic differentiation of ocular tissues. Changes may include any combination of choroidal vascular hypoplasia, retinal pigment epithelial (RPE) and/or tapetal defects, abnormal retinal vasculature, scleral colobomas (typically involving the region surrounding the optic nerve head), retinal dysplasia and/or retinal detachment (partial or complete). Changes are bilateral but not always symmetrical. Most affected animals are clinically asymptomatic, abnormalities only being detected upon fundic examination, however, patients may present as a result of symptoms associated with retinal detachment and/or hyphema. Commonly affected breeds include the Collie breeds, Australian Shepherd & Shetland Sheepdog.