Ocular Surface Squamous Neoplasia Treatment

Ocular surface squamous neoplasia (OSSN) are usually found around the limbus, with prominent feeder blood vessels, and are often gelatinous in appearance. They are malignant. Risk factors for OSSN include exposure to sunlight, fair skin/pale iris, human papilloma virus and HIV, cigarette smoking, chronic contact lens use, and chronic inflammation.

The treatment for OSSN generally involves surgical excision and eye drops. Surgery requires cutting the OSSN from the surface of the eye and the lesion can then be sent for pathology testing to ensure the diagnosis is correct and to check for clear margins. Medical treatments may be Mitomycin-C or Interferon alpha 2b, which as eye drops, are able to treat the entire ocular surface for abnormal cells. The use of these medications is off label. Off label use is based on firm scientific method and sound medical evidence, but means that the drug has been approved by the Food and Drug Administration (FDA) for a different treatment originally. Interferon is generally better tolerated but does need to be used for longer than mitomycin C (see Mitomycin C).

Interferon

This drug is often used in the treatment of precancerous ocular lesions, which in a percentage of cases may proceed to become frank ocular surface cancer of the eye. While Interferon has been used for many years by injection for the treatment of viral infections, multiple sclerosis and in some cases treatment of tumours. The side effects of the drug when administered by injection have been well documented over the years but only more recently has it been used as an eye drop. There is much publicised literature regarding the use of Interferon as an eye drop but to date there has been very little reported in the way of complications, apart from minor eye irritation associated with the administration of the eye drop. You should follow the prescribed course of drops recommended by your doctor.

Drops need to be taken for a period of weeks to months, and can be a little irritant. Generally follow up visits are recommended to watch for any recurrence, however treatment is usually very effective with good visual results