Melanoma skin cancer usually begins in new or changing moles, and in some cases leads to serious complications if not detected early.
Although melanoma skin cancer most commonly appears on the skin, it can also affect less common areas such as the eyelids and eyes. The eyelids, with their thin layers, are exposed to harmful ultraviolet radiation, making them susceptible to cancerous lesions. If left untreated, these tumors can spread inwards, reaching the eye and brain, making treatment more difficult.
Cancer can also begin inside the eye itself in a form known as ocular melanoma, which includes several subtypes, most notably:
Skin and eye cells are similar in that they are pigment cells, producing melanin, which is responsible for the color of skin, eyes, and hair. Damage to these cells or mutations in them can lead to cancer.
Unlike skin cancer, ocular or conjunctival melanoma is not primarily associated with ultraviolet radiation, but people with light-colored eyes or eye problems, such as nearsightedness, may be more susceptible.
Eye doctors recommend having regular eye exams every year or two, and paying attention to any minor changes such as blurred vision, spots, or irritation in or around the eye.
Symptoms of ocular melanoma do not usually appear in the early stages, but as the disease progresses, patients may experience blurred vision, seeing floaters or flashes of light, or changes in the shape of the pupil.
Conjunctival melanoma, which develops in the conjunctiva (the clear tissue covering the eye), is very rare. Its symptoms include irritation, redness, or a feeling of having a foreign body in the eye, and its progression may lead to vision loss or a change in pupil size.
Uveal melanoma begins in the middle layer of the eye, called the uvea, which includes the iris, ciliary body, and choroid. It is the most common type of eye cancer in adults. The causes of this type are unclear, and ultraviolet radiation is not believed to play a role.
Bowen said: "Some of the most dangerous types of eye cancer, particularly uveal melanoma, often do not cause pain or changes in vision in the early and even middle stages. This type is life-threatening because it can spread through the retina to the brain if not detected early."
Bowen urged anyone who notices changes in their eyes or vision to visit an ophthalmologist immediately, especially if symptoms persist for several weeks or worsen, stressing the importance of early detection for all ages, including children, to detect rare, life-threatening tumors such as retinoblastoma.
