Contributor: Gordon K. Klintworth
Nevus of Ota (oculodermal melanocytosis) is a congenital disorder of melanocytes characterized by a discoloration of the conjunctiva, skin of the eyelids, uvea and periocular orbital tissue due to the presence of excessive pigmented melanocytes. Heterochromia iridis is present and the episclera has a grayish discoloration. The fundus is dark. A benign clinical course usually ensues, but the nevus may carry a very slight risk for uveal melanoma [melanoma - uvea]. Dendritic melanocytes are located deep in the conjunctival substantia propria and episcleral tissues. Patients with the nevus of Ota have an associated blue nevus [nevus - blue] of the periocular skin. Heterochromia iridis (involved eye darker) reflects an associated diffuse nevus of the uvea that can give rise to a uveal malignant melanoma.