What are conjunctival pigmented lesions?

The conjunctiva (the transparent skin over the white of the eye) sometimes develops brown discolouration. This is classified according to the cause:

Hypermelanosis: melanocytes (the cells of the body that produce the dark pigment melanin) go into overproduction. This may be a normal characteristic , or it may be caused by disease elsewhere in the body.

Primary Acquired Melanosis: unusually large numbers of melanocytes develop. This is rare in dark-skinned races and tends to affect older white-skinned people.

Congenital Melanocytosis: similar, except present from birth.

A Naevus, that is a brown spot on the conjunctiva, may be present from birth or may arise later. This is the commonest of all the conjunctival pigmented lesions. Usually it does not grow or spread.

Sometimes, a naevus changes into an Invasive Melanoma, also known as a Malignant Melanoma, which can spread to other parts of the body. This particularly affects people with fair complexions and is seen only very rarely in dark-skinned people.

There are also some uncommon generalised diseases that may produce discolouration of the conjunctiva. Some prescription drugs may also cause a similar effect.

How are conjunctival pigmented lesions managed?

Depending on the nature of the pigmented lesion, optometrists may monitor the condition themselves, or refer to an ophthalmologist routinely or urgently. Mild ethnic melanosis does not need to be referred.

The ophthalmologist will carry out tests to identify which condition the patient has. Melanoma is usually treated with surgery and additional drug therapy. Careful follow-up is required due to high rates of recurrence.