Although ocular melanoma is the most common primary intraocular malignancy in adults, and the second most likely location for primary melanoma after the skin, it is still exceedingly rare. In the Causasian population, it has an average annual incidence of 6 cases per million, with approximately 1200 cases diagnosed each year. Ocular melanoma occurs in the uvea much more commonly than in the conjunctiva, at a ratio of 35:1. Conjunctival melanomas have a propensity for regional spread to the lymph nodes analogous to cutaneous disease, with 10-year survival rates of more than 80%.3
In this case, the patient had this dark spot since childhood and had noted no growth or change. It was consistent with a conjunctival nevus and did not need biopsy.
Diagnostic tests: only for cases that do not respond
When viral conjunctivitis is suspected, no laboratory tests are routinely recommended. Bacterial and viral cultures may be helpful to establish the diagnosis in cases that do not resolve or when patients have recurrent episodes. Infections that do not respond to empiric treatment should be cultured for the suspected organisms (bacteria, chlamydia, or herpes simplex). When chlamydial conjunctivitis is suspected, the diagnosis should be confirmed by means of an immunodiagnostic test (direct fluorescent antibody [DFA]) or culture (level of evidence [LOE]=1a).4
A fluorescein exam is helpful in cases with a question of corneal involvement from foreign-body trauma, herpes simplex, or epidemic kerato-conjunctivitis. Herpes simplex infections have a dendritic pattern of ulceration, and epidemic keratoconjunctivitis infections cause multiple small areas of increased fluorescein uptake.