Normal: A “Normal” eye rating is of course the best grading there is. (There are also "Go Normals", which are so mildly affected at a young age, that later, the pale areas disappear, leading to what is termed a "Go Normal". Keep in mind that these are still in fact affected with CEA). There are variations even in "Normal" eyes. These correspond somewhat to a dog's coat color. Thus it is often difficult to judge the pigment in a Blue Merle's eyes as it is diluted along with his coat color.

Choroidal Hypoplasia, Chorioretinal Change:These refer to abnormalities in the coloring or pigmentation of the choroid or central layer of the eye's lining. This is the most common abnormality found in Collie eyes. Often referred to as mild CRC, Grade I or Grade II, it is the least harmful and least severe form of CEA. Most dogs with this eye grade function normally with no ill-effects or loss of vision.

Staphyloma, Coloboma, Ectasia: While not completely synonymous, these terms all refer to a cupping or bulging in the eyeball usually in the area of the optic disc.

Vascular Disease, Tortuous Blood Vessels:Defects in the vessels of the eye which are responsible for its blood supply or "nourishment." These may be malformed, undersized, or even lacking.

Retinal Detachment: Loosening or separation of the inmost, or retina, layer from the wall of the eye. This may involve a tiny area or the entire retina. It can be either one or both eyes. The complete detachment of the retina results in blindness in that eye.

Merle Collies

The fundus of the Merle Collies present a special challenge in differentiating affected individuals from non-affected in terms of Collie eye anomaly. The Merle fundus is often lightly pigmented and exhibits a normal amount of choroid hypoplasia. Some of these individuals cannot be designated as normal based on a clinical examination. Test breeding may be required.

There is a new Genetic Test for Collie Eye Anomaly / Choroidal Hypoplasia. Please visit the OPTIGEN website for details

The OptiGen genetic test for CEA/CH provides a powerful management tool for the breeder. This genetic test can distinguish all three genetic states – normal, carrier and affected. With this information, the breeder can plan matings that avoid producing any affected dogs by always selecting one parent that is normal. The other parent can be normal, carrier or even affected, and no affected dogs will result. (See table at the end.) This breeding recommendation is a big step forward, especially for breeds and countries where frequency of CEA/CH is much lower. Earlier advice cautioned against breeding affected dogs, their parents, their offspring or their siblings (unless eye exams before 3 months of age demonstrate the sib is unaffected).

Understandably, genetic testing will be a difficult tool to use for some breeders of “standard” collies (i.e., Rough, Smooth, Show, Standard) where the disease is very common. In some circumstances, genetically normal – homozygous normal – collies could be difficult to find and it may not be practical for the breeder to plan matings that include one normal dog. And, it may not be reasonable to expect complete avoidance of CEA/CH in one generation. All the same, genetic testing is a sure-fire tool to move toward elimination of the disease. To start, breeding a carrier to a carrier will produce an average of 25% normals, 50% carriers and 25% affecteds. With genetic testing at each subsequent generation, and with a goal of breeding normal by carrier or normal by affected, the frequency of disease will drop and frequency of normals will increase without loss of other desirable traits valued in collies.