Collie Eye Anomaly (CEA) is a genetic mutation affecting many breeds that causes developmental defects in the eye that can lead to vision deficits or blindness. This defect can be diagnosed by a veterinary ophthalmologist between 6 and 8 weeks of age by visualizing spots of choroidal hypoplasia or a colobomas . It can be associated with microphthalmia or enophthalmia. It can lead to retinal detachment and blindness. Although laser repair of partial retinal detachments can be attempted if detected in early stages, there is generally no treatment for CEA. Vision varies depending on the extent of the lesions and some dogs will become blind. Prevention requires not breeding animals that carry the mutation and this can be achieved through genetic testing of breeding dogs.