Corneal and conjunctival effects of monobenzone in patients with vitiligo

Monobenzone (the monobenzyl ether of hydroquinone [Benoquin]) is used topically by patients with extensive vitiligo to depigment their remaining normally pigmented skin. A patient who had been applying the drug for one year had an anterior linear deposition of pigment in both corneas. Of 15 additional patients with vitiligo, 11 of whom were using monobenzone, acquired conjunctival melanosis in two patients and pingueculae in three may have been related to monobenzone use. Light and electron microscopy of one corneal epithelial scraping and 12 conjunctival biopsy specimens revealed pleomorphic, single-membrane-limited intracytoplasmic inclusions within the corneal epithelium and within the epithelium, fibrocytes, histiocytes, and vascular endothelium of the conjunctiva. The ultrastructural aspects of these inclusions suggested that they are residual bodies containing lipid and lipofuscin.