At least 50 people have been diagnosed with a rare type of eye cancer called ocular melanoma. They are all residents of two locations - Huntersville, North Carolina, and Auburn, Alabama. The cancer is rare and occurs in only six per 1 million population. The high rate of incidence of this cancer in these two locations has stumped researchers.
One of the connecting factors seen in 38 of these individuals was the fact that they had attended Auburn University between 1983 and 2001. Till date at least 4 individuals have succumbed to this cancer. What is surprising is the number of people affected with this cancer in such a concentrated manner, say experts. Ocular melanomas are the second common form of melanoma after skin cancers or cutaneous melanomas. They are 5 percent of all melanomas. These are however more life-threatening than skin melanomas say experts.
Ocular melanoma is a malignant cancer that affects the pigment or melanin producing cells or melanocytes. These melanocytes are present over the skin, eyes and hair and some internal organs. The provide color. There are three layers in the eye ball – the outer white sclera, the inner sensitive and nerve rich retina and the middle layer uvea. Ocular melanomas occur in the uveal layer of the eye. These melanomas are usually picked up as small spots over the pupils and patients complain of blurred vision or spots, flashes and floaters in the visual field. There may be progressive vision loss.
People with light colored blue or green eyes and light colored skin are more at risk of ocular melanomas. Those exposed to high levels of UV radiation remain at greater risk just like in skin cancers. Cooks and metal workers are seen to have a greater risk of these melanomas.
For diagnosis of these melanomas a dilated eye exam by and eye specialist is routine. Some of the other tests include ultrasound of the eye, Fluorescein angiography, fundus autofluorescence and optical coherence tomography (OCT). A biopsy may also be taken from the tumor to examine it under the microscope.
In nearly half of the cases the cancer spreads from the eye to other parts of the body, notably the liver. Once the cancer has spread to the liver, the chances of survival are drastically reduced with around 20 percent individuals surviving for less than a year.
What is worrisome is that ocular melanoma has no known cure as yet. Surgery is the first course of action usually to remove the tumour. Thereafter radiation therapy is usually employed to prolong life and keep the cancer from returning.