Corneal sequestrations, also known as corneal mummification, corneal necrosis, and corneal nigrum have been reported in the United States and Europe and are a unique disease process affecting the cornea of the domestic cat. The lesions usually develop slowly, are light brown to brown to black in color, and are usually located in the center of one or both corneas. The disease process may also present with corneal blood vessels and commonly induces pain (exhibited by squinting, redness, and excessive tearing). All feline breeds may be affected but corneal sequestrations occur disproportionately in Persians and Himalayans, and to a lesser extent in Siamese. Male and female cats are equally affected and most affected cats are between the ages of two and seven years. The disease is associated with a degeneration of the corneal tissue but the specific cause has yet to be identified. Feline Herpesvirus (Feline Viral Rhinotracheitis) has been incriminated as well as genetic factors such as the anatomical makeup of the affected cats (e.g., prominent eyes).
The lesions may spontaneously slough, but the time from the early development of the lesion to sloughing is quite variable. Specific route of treatment is recommended on a case by case basis per Dr. Dugan’s or Dr. Best’s findings. Options include either conservative medical management (i.e. prescription topical eyedrops) or surgical intervention (surgical removal of the lesion). If the cat is comfortable, medical therapy may be tried. Nonetheless, lesions may recur in the same eye despite successful medical or surgical therapy, or a new lesion may develop in the other previously normal eye at a later date. Consequently, once a corneal sequestration has been diagnosed and treated, the affected cat should be closely monitored for the development of a recurrence in the previous surgical site and/or the emergence of a new lesion in a different location on the same eye or on the cornea of the other eye.