Heterochromia : It is the case when both irises have different colors (full), or when in a single iris there are areas of different colors
(partial or sectorial). It can be congenital or acquired. Congenital may be associated with Neurofibromatosis, Waardenburg syndrome or Claude Bernard – Horner syndrome. It is common in dogs, cats and horses.
Aniridia: bilateral, heritable and unusual. It is the total absence of the iris caused by an alteration of chromosome 11. The affected persons have low vision and photophobia, cataract, glaucoma, nystagmus, and macular and foveal hypoplasia.
Albinismo: It is the complete absence of melanin in the skin, eyes and hair. In the severe grade, the eyes have red or even purple appearance. Affected persons suffer from photophobia, nystagmus, strabismus, myopia and astigmatism.
Kayser- Fleischer ring: Consists of copper deposition in the corneal periphery, and it has golden-greenish color. It is part of the Wilson ‘s disease or hepato – lenticular degeneration (widespread deposition of copper in tissues: liver, nervous system, cornea,…) and it is present with psychiatric symptoms, given the high toxicity to the tissue of the mineral.