Perhaps you've heard of melanoma. It develops from the cells that produce the dark-colored pigment melanin, which is responsible for our skin's coloring. These cells, called melanocytes, are found in other places in our bodies, too: our hair, the lining of our internal organs, and our eyes. So while most melanomas do form on the skin, it is possible for a melanoma to form elsewhere. When it forms in the eye, it’s known as ocular melanoma or, more specifically, uveal melanoma.
OM is much rarer than skin melanoma and behaves quite differently. There are other types of eye cancers, but OM is the most common in adults and the most dangerous. It's a potentially lethal disease which many people die from, especially when it spreads to the liver, a complication in about half of people diagnosed with this disease.
No one knows for sure why OM tumors form but there is heightened prevalence amongst fair-skinned and blue-eyed individuals. Originally, excessive exposure to sunlight was thought to be a key risk factor but no study has proven a direct linkage to development of OM tumors.
OM tumors arise from the pigment cells (melanocytes) that give color to the eye. Formation of these tumors is quite rare and, as for many other forms of cancer, the exact cause is unknown. It is known that exposure to ultraviolet (UV) rays (either from the sun or sunbeds) increases the risk of developing melanoma of the skin. People whose skin burns easily are most at risk – people with fair skin, fair or red hair and blue eyes. However, there has no conclusive evidence linking UV exposure and OM.
Ocular melanoma may be more common in people who have atypical mole syndrome, which is also called dysplastic naevus syndrome. People with this condition have a greater risk of developing a melanoma of the skin, and often have over 100 moles on their body, some of which are abnormal in size and shape.
Approximately 2,500 adults are diagnosed with ocular melanoma every year. There is no known cause, though incidence is highest among people with lighter skin and blue eyes.
Approximately 50% of patients with OM will develop metastases by 10 to 15 years after diagnosis (a small percentage of people will develop metastases even later i.e. 20-25 years after their initial diagnosis). Metastatic disease is universally fatal. This 50% mortality rate is unchanged despite treatment advances in treating the primary eye tumor. More research is needed urgently to improve patient outcomes
Emerging techniques to eradicate OM:
- Transpupillary Thermotherapy
- Trans-Sclera Local Resection
- Plaque Radiotherapy
- Trans-Retinal Endoresection.