Melanoma is a cancer that develops from cells called melanocytes. Melanocytes produce the dark-coloured pigment melanin, which is responsible for the colour of our skin. These cells are found in many places of the body, including: the skin, hair and lining of the internal organs, as well as the eye.
Most of the time melanomas begin to grow on the skin, but it is possible for melanoma to develop in other parts of the body, such as the eye. An ocular melanoma can develop in a variety of anatomical places within the eye. Uveal melanoma is the most common type; this tumor occurs along the uveal tract of the eye, which includes the choroid, ciliary body and iris.
The choroid is part of a layer found within the eyeball. The choroid is darkly pigmented to prevent light from reflecting inside of the eye. The ciliary body extends from the choroid and helps the eye focus by changing the shape of the lens. The iris is the coloured disc at the front of the eye whose job is to control the amount of light that enters the eye. All these structures within the eye are coloured with melanin. Melanoma can also be present in the thin lining over the white part of the eye (the conjunctiva) or on the eyelid, but are very rare. This is known as conjunctival melanoma. The ocular melanoma is the most common type of cancer to affect the eye, although it’s still quite rare.
Symptoms of an ocular melanoma include blurred vision, seeing flashing lights and shadows. However, patients are usually asymptomatic and can be diagnosed by an optometrist during a routine comprehensive eye exam.
Risk factors for primary melanoma of the eye include:
Complications of eye melanoma may include:
A number of different treatments are used for ocular melanoma. The treatment modality depends on the size, cell type and position of the tumour and on other factors such as your general health and level of vision in both eyes. The aim of treatment is to destroy the cancer cells, stop the cancer from coming back and to save as much vision as possible.