DNA test - CEA/CH
Collie eye anomaly / Choroidal hypoplasia
Collie Eye Anomaly (CEA) is more technically known as Choroidal Hypoplasia (CH). It is a recessively inherited eye disorder that causes abnormal development of the choroid - an important layer of tissue under the retina of the eye. Since the choroid layer does not develop normally from the start, the primary abnormality can be diagnosed at a very young age. The symptoms and signs vary greatly among affected dogs within one breed, between parent and offspring and even within a litter. Most often the disease presents as a mild form in affected dogs and the presence of the disease can only be detected upon ophthalmologic examination; the dog retains normal vision throughout life. However, dogs with mild disease can produce severely affected offspring. The severe form of the disease presents with related problems with the health of the eye that can result in serious vision loss in some cases.
Source of DNA Test: http://www.thekennelclub.org.uk/download/8288/dnatestsworldwide.pdf