The lesion is a corneal sequestrum, seen only in the cat, and representing a stromal necrosis. The lesion might well be seen as a final common pathway for a number of corneal conditions; in Persian and Colourpoint breeds it occurs probably associated with corneal anaesthesia seen in these breeds; in domestic short-haired cats it can be associated with feline herpesvirus. Treatment is surgical with removal of diseased tissue by a superficial keratectomy. The lesion can slough naturally but early surgery is probably to be advised; leaving it too long can result in a very deep lesion as seen here, where removal of the superficial layers still leaves diseased tissue. A full thickness graft or deep lamellar keraectomy with tectonic graft are the only surgical options.