Eye cancer is a real medical condition, though it is considered rare compared to other types of cancer. It is defined by the uncontrolled growth of abnormal cells that form a malignant tumor within the structures of the eye or the tissues surrounding it. This disease can affect the eyeball itself (intraocular) or accessory structures like the eyelids and the orbit. The growth of these malignant cells can destroy healthy tissue and has the potential to spread to other parts of the body.
Primary and Secondary Ocular Malignancies
Ocular malignancies are broadly categorized based on where the cancer originates in the body. Primary eye cancers begin directly in the tissues of the eye, while secondary, or metastatic, eye cancers spread to the eye from a tumor located elsewhere. Secondary eye cancer is actually the most common form of malignancy found in the eye in adults, often originating from cancers of the breast or lung.
The most common primary eye cancer in adults is uveal melanoma, which arises from the pigment-producing cells in the uvea, the middle layer of the eyeball. This layer includes the iris, ciliary body, and the choroid, with most melanomas starting in the blood-vessel-rich choroid. Another primary type is intraocular lymphoma, which involves white blood cells and is more common in older individuals or those with compromised immune systems. For children, the most common primary intraocular cancer is retinoblastoma, a tumor that begins in the light-sensitive retina tissue at the back of the eye.
Recognizing Common Warning Signs
While eye cancer often produces no symptoms in its early stages, several observable changes may prompt a visit to an eye care specialist. A patient might notice a change in their vision, such as new or worsening blurriness, or the sudden loss of a portion of their visual field. The perception of flashes of light or an increase in floating specks, known as floaters, can also be a sign, though these are often caused by less serious conditions.
Physical changes to the eye’s appearance are also potential warning signs. This could include a dark spot on the iris that appears to be growing larger. Other noticeable symptoms involve the surrounding structures, such as a bulging of the eyeball, a change in the way the eye moves, or a lump on the eyelid that does not heal. Persistent pain or irritation in or around the eye that does not resolve should also be evaluated.
Key Risk Factors and Genetic Predispositions
Several factors are known to increase a person’s susceptibility to eye cancer, particularly uveal melanoma. Non-modifiable risks include having a lighter eye color, such as blue or green, and a fair skin tone that freckles or sunburns easily. Age is another factor, with the average age of diagnosis for eye melanoma being around 60 years.
Specific inherited genetic conditions are also linked to a higher risk of developing certain eye cancers. The BAP1 tumor predisposition syndrome, for example, is a rare inherited condition caused by a mutation in the BAP1 gene that significantly increases the lifetime risk of uveal melanoma. For retinoblastoma in children, about 40% of cases are heritable, caused by a mutation in the RB1 gene that is passed down and often affects both eyes. Excessive exposure to ultraviolet (UV) radiation from sunlight is a modifiable risk factor, particularly for squamous cell carcinoma of the eye and potentially for melanoma.
Modern Approaches to Diagnosis and Treatment
Diagnosis often starts with a comprehensive eye examination that includes an ophthalmoscopy to look inside the eye. Imaging techniques are employed to confirm the presence of a tumor and determine its size and location. An eye ultrasound, or B-scan ultrasonography, uses sound waves to create detailed images of the internal eye structures, which is useful for measuring the tumor.
Advanced imaging, such as CT scans, MRI, or PET scans, help determine if the cancer has spread beyond the eyeball to the orbit or other parts of the body. In some cases, a biopsy may be performed, where a small tissue sample is removed from the tumor and analyzed to confirm the cancer type and provide genetic profiling. This genetic analysis can help predict the likelihood of the cancer spreading, guiding subsequent treatment decisions.
Treatment aims to eliminate the cancer while preserving the patient’s vision and the eye structure whenever possible. Radiation therapy is a common approach, often delivered through brachytherapy, which involves surgically placing a small, custom-designed radioactive plaque directly onto the tumor. This plaque contains radioactive seeds and delivers a high dose of radiation over several days before being surgically removed, minimizing damage to surrounding healthy tissue. External beam radiation therapy, such as proton beam radiation, is another precise method that directs radiation from an outside machine toward the tumor.
Surgical options range from local resection, which removes only the tumor or a small part of the eye, to enucleation, the complete removal of the eyeball. Enucleation is typically reserved for very large tumors or when vision cannot be saved. Laser therapy, such as transpupillary thermotherapy (TTT), uses concentrated heat from an infrared light to destroy small tumors, sometimes used in conjunction with brachytherapy. For metastatic disease, systemic therapies like chemotherapy, targeted molecular therapy, or immunotherapy may be used to treat cancer that has spread outside the eye.