This is an inherited disorder of the eyes caused by a mutation within the retinol-binding protein gene (RBP4), responsible for carrying vitamin A (retinol) to peripheral tissues, including eye, where is participates in the development of the eye.

Affected dogs have small eyes which seems to be recessed in the eye socket, condition known as enophthalmos. Also, third eyelids may be prominent. These characteristics are often associated with other eye disorders, such as the abnormalities of the cornea, anterior chamber, lens or retina.

Other symptoms may appear, such as clumsy behaviour, anxiety, difficulties with coordination, asocial behaviour, excessive sleepiness, partial vision loss.