Microphthalmia is an inherited eye disease affecting dogs. Microphthalmia results from a vitamin A deficiency during gestation which produces under-developed eyes that are smaller than normal. In addition, the layer of tissue in the eye responsible for supplying blood and nutrients to the Retina, called the choroid layer, is affected. Dogs affected with Microphthalmia may also present with malformations of the optic nerve, known as a Coloboma and may have variable loss of vision. Eye abnormalities are evident as soon as the puppy’s eyes open. A veterinarian may observe these abnormalities during an initial eye exam and can assess for any vision loss.