Precancerous conditions of the eye

Precancerous conditions of the eye are changes to eye cells that make them more likely to develop into cancer. These conditions are not yet cancer. But if they aren’t treated, there is a chance that these abnormal changes may become eye cancer.

The most common precancerous conditions of the eye are:

  • primary acquired melanosis (PAM)
  • ocular melanocytosis
  • conjunctival intraepithelial neoplasia

Primary acquired melanosis (PAM)

PAM is a condition of the conjunctiva – a clear mucous membrane that covers the inner surface of the eyelids and the outer surface of the eye. It is most common in fair-skinned Caucasians who are middle age or older. PAM most often appears as a flat, brown patch on one of the eyes that is easily seen against the white of the eye (the sclera). The brown patch has a high number of melanocytes. Melanocytes are the cells that make melanin, the substance that gives colour to our skin, hair and eyes. Most melanomas of the conjunctiva are thought to develop from PAM.


PAM is usually diagnosed by an eye care specialist. If you have signs of PAM you should have your eyes checked each year to look for changes. See your optometrist or ophthalmologist if you notice a change before your next appointment.

If your doctor suspects PAM, you may need to have a biopsy to remove some tissue from the abnormal area.


Treatment options for PAM may include:

  • watchful waiting – regular eye exams to look for changes
  • surgery to remove the abnormal area
  • cryosurgery – uses extreme cold to freeze and destroy abnormal tissue
  • chemotherapy drug put directly on the skin (topical chemotherapy) – mitomycin

Ocular melanocytosis

People with ocular melanocytosis have a high number of melanocytes and extra melanin in and around the eyes. Ocular melanocytosis may develop into melanoma of the uvea (a layer in the wall of the eye), a type of intraocular melanoma or melanoma of the eye socket (orbital melanoma). Ocular melanocytosis also carries a risk of developing melanoma in the brain. Ocular melanocytosis is also called oculodermal melanocytosis or nevus of Ota when it affects the eyelid.


Ocular melanocytosis is diagnosed by an optometrist or ophthalmologist. You may also have an ultrasound of the eye to rule out melanoma.

You may also see a neurologist, a doctor who specializes in conditions that affect the nervous system. They look for signs of cancer in the brain.


Most people with ocular melanocytosis don’t need treatment. But it’s important to go for regular medical and eye exams to look for changes that may suggest cancer.

Conjunctival intraepithelial neoplasia

Conjunctival intraepithelial neoplasia develops when the cells of the conjunctiva change and become precancerous cells. This condition may be seen as a white or yellowish thickening on the surface of the eye. The eye may look red, somewhat like conjunctivitis (a condition commonly known as pink eye). Conjunctival intraepithelial neoplasia may develop into squamous cell carcinoma of the conjunctiva if it’s not treated.


Tests used to diagnose conjunctival intraepithelial neoplasia may include:

  • an eye exam
  • an ultrasound
  • a biopsy


Treatment options for conjunctival intraepithelial neoplasia include:

  • surgery with or without cryosurgery
  • topical chemotherapy with mitomycin C or 5-fluorouracil (Efudex, 5-FU)
  • topical immunotherapy with interferon alfa-2b (Intron A)

Expert review and references