CEA

CEA "is a genetic disorder of the eye found in multiple breeds, including most frequently in herding dogs, especially collies and Shetland sheepdogs. The mutation affects the inner structures of the eye, such as the choroid, the retina and the optic disk" (Jourdain, 2024).

According to U.C. Davis "Affected dogs may also present with small eyeballs (microphthalmia), mineralization of the cornea, bleeding inside the eye, detachment of the retina, impaired vision or even blindness due to coloboma of the optic nerve. 

"The condition is inherited in an autosomal recessive manner, meaning that dogs must have two copies of the disease allele to be affected. Dogs with one copy of the disease allele are normal but can pass on the disease allele to their puppies" (Collie Eye Anomaly (CEA) | Veterinary Genetics Laboratory, n.d.-b).