Appaloosa occurs in several overlay patterns on one of several recognized base coat colors. There are three other distinctive, "core" characteristics: mottled skin, striped hooves, and eyes with a white sclera. Skin mottling is usually seen around the muzzle, eyes, anus, and genitalia. Striped hooves are a common trait, quite noticeable on Appaloosas, but not unique to the breed. The sclera is the part of the eye surrounding the iris; although all horses show white around the eye if the eye is rolled back, to have a readily visible white sclera with the eye in a normal position is a distinctive
Enucleation of the eye To avoid a sunken appearance to the eye socket, an implant approximating this volume can be placed into the space of the removed eye, secured, and covered with Tenon's capsule and conjunctiva (the mucous membrane covering the natural sclera). Implants can be made of many materials with the most common being plastic, hydroxylapatite, metal alloy or glass. Later, once the conjunctiva have healed and post-operative swelling has subsided, an ocular prosthesis can be placed to provide the appearance of a natural eye. The prosthesis is fabricated by an ocularist. Its form is that of a cupped disc so that it