Melanoma is a type of cancer that develops in the cells that produce melanin — the pigment that gives your skin its color. Your eyes also have melanin-producing cells and can develop melanoma. Eye melanoma is also called ocular melanoma.
Most eye melanomas form in the part of the eye you can’t see when looking in a mirror. This makes eye melanoma difficult to detect. In addition, eye melanoma typically doesn’t cause early signs or symptoms.
Treatment is available for eye melanomas. Treatment for some small eye melanomas may not interfere with your vision. However, treatment for large eye melanomas typically causes some vision loss.
Types of Ocular Melanoma
Uveal and nonuveal ocular melanoma are two types of ocular melanoma. The most common type of ocular melanoma is uveal melanoma, which includes choroid, ciliary body, and iris melanoma. When compared to iris or anterior uveal melanoma, choroidal and ciliary body melanoma are collectively referred to as posterior uveal melanoma. The most uncommon uveal melanoma is iris melanoma.
All conjunctival melanomas are nonuveal melanomas (CM). Melanocytes in the basal layer of the conjunctival membrane’s epithelium give rise to conjunctival melanomas. Conjunctival melanoma is extremely rare, accounting for around 5% of all ocular melanomas.
Symptoms
Eye melanoma may not cause signs and symptoms. When they do occur, signs and symptoms of eye melanoma can include:
- A sensation of flashes or specks of dust in your vision (floaters)
- A growing dark spot on the iris
- A change in the shape of the dark circle (pupil) at the center of your eye
- Poor or blurry vision in one eye
- Loss of peripheral vision.
Where eye melanoma occurs
Eye melanoma most commonly develops in the cells of the middle layer of your eye (uvea). The uvea has three parts and each can be affected by eye melanoma:
- The iris, which is the colored part in the front of the eye
- The choroid layer, which is the layer of blood vessels and connective tissue between the sclera and the retina at the back of the uvea
- The ciliary body, which is in the front of the uvea and secretes the transparent liquid (aqueous humor) into the eye.
Eye melanoma can also occur on the outermost layer on the front of the eye (conjunctiva), in the socket that surrounds the eyeball and on the eyelid, though these types of eye melanoma are very rare.
Causes
It’s not clear what causes eye melanoma.
Doctors know that eye melanoma occurs when errors develop in the DNA of healthy eye cells. The DNA errors tell the cells to grow and multiply out of control, so the mutated cells go on living when they would normally die. The mutated cells accumulate in the eye and form an eye melanoma.
Risk factors
Risk factors for primary melanoma of the eye include:
- Light eye color. People with blue eyes or green eyes have a greater risk of melanoma of the eye.
- Being white. White people have a greater risk of eye melanoma than do people of other races.
- Age. The risk of eye melanoma increases with age.
- Certain inherited skin disorders. A condition called dysplastic nevus syndrome, which causes abnormal moles, may increase your risk of developing melanoma on your skin and in your eye.
In addition, people with abnormal skin pigmentation involving the eyelids and adjacent tissues and increased pigmentation on their uvea — known as ocular melanocytosis — also have an increased risk of developing eye melanoma.
- Exposure to ultraviolet (UV) light. The role of ultraviolet exposure in eye melanoma is unclear. There’s some evidence that exposure to UV light, such as light from the sun or from tanning beds, may increase the risk of eye melanoma.
- Certain genetic mutations. Certain genes passed from parents to children may increase the risk of eye melanoma.
Complications
Complications of eye melanoma may include:
- Increasing pressure within the eye (glaucoma). A growing eye melanoma may cause glaucoma. Signs and symptoms of glaucoma may include eye pain and redness, as well as blurry vision.
- Vision loss. Large eye melanomas often cause vision loss in the affected eye and can cause complications, such as retinal detachment, that also cause vision loss.
Small eye melanomas can cause some vision loss if they occur in critical parts of the eye. You may have difficulty seeing in the center of your vision or on the side. Very advanced eye melanomas can cause complete vision loss.
- Eye melanoma that spreads beyond the eye. Eye melanoma can spread outside of the eye and to distant areas of the body, including the liver, lungs and bones.
Diagnosis
To diagnose eye melanoma, your doctor may recommend:
- Eye exam. Your doctor will examine the outside of your eye, looking for enlarged blood vessels that can indicate a tumor inside your eye. Then, with the help of instruments, your doctor will look inside your eye.
- One method, called binocular indirect ophthalmoscopy, uses lenses and a bright light mounted on your doctor’s forehead — a bit like a miner’s lamp. Another method, called slit-lamp biomicroscopy, uses lenses and a microscope that produces an intense beam of light to illuminate the interior of your eye.
- Eye ultrasound. An eye ultrasound uses high-frequency sound waves from a hand-held, wandlike apparatus called a transducer to produce images of your eye. The transducer is placed on your closed eyelid or on the front surface of your eye.
- Imaging of the blood vessels in and around the tumor (angiogram). During an angiogram of your eye, a colored dye is injected into a vein in your arm. The dye travels to the blood vessels in your eye.
A camera with special filters to detect the dye takes flash pictures every few seconds for several minutes.
- Optical coherence tomography. The imaging test creates pictures of portions of the uveal tract and retina.
- Removing a sample of suspicious tissue for testing. In some cases, your doctor may recommend a procedure to remove a sample of tissue (biopsy) from your eye.
To remove the sample, a thin needle is inserted into your eye and used to extract suspicious tissue. The tissue is tested in a laboratory to determine whether it contains eye melanoma cells.
An eye biopsy isn’t usually necessary to diagnose eye melanoma.
Determining whether cancer has spread
Your doctor may recommend additional tests and procedures to determine whether the melanoma has spread (metastasized) to other parts of your body. Tests may include:
- Blood tests to measure liver function
- Chest X-ray
- Computerized tomography (CT) scan
- Magnetic resonance imaging (MRI) scan
- Abdominal ultrasound
- Positron emission tomography (PET) scan.
Treatment
Your eye melanoma treatment options will depend on the location and size of the eye melanoma, as well as your overall health and your preferences.
Waiting to treat small eye melanomas
A small eye melanoma may not require immediate treatment. If the melanoma is small and isn’t growing, you and your doctor may choose to wait and watch for signs of growth.
If the melanoma grows or causes complications, you may choose to undergo treatment at that time.
Radiation therapy
Radiation therapy uses high-powered energy, such as protons or gamma rays, to kill cancer cells. Radiation therapy is typically used for small to medium-sized eye melanomas.
The radiation is usually delivered to the tumor by placing a radioactive plaque on your eye, directly over the tumor in a procedure called brachytherapy. The plaque is held in place with temporary stitches. The plaque looks similar to a bottle cap and contains several radioactive seeds. The plaque remains in place for four to five days before it’s removed.
The radiation can also come from a machine that directs radiation, such as proton beams, to your eye (external beam radiation, or teletherapy). This type of radiation therapy is often administered over several days.
Laser treatment
Treatment that uses a laser to kill the melanoma cells may be an option in certain situations. One type of laser treatment, called thermotherapy, uses an infrared laser and is sometimes used in combination with radiation therapy.
Photodynamic therapy
Photodynamic therapy combines medications with a special wavelength of light. The medicine makes the cancer cells vulnerable to light. The treatment damages the vessels and the cells that make up the eye melanoma. Photodynamic therapy is used in smaller tumors, as it isn’t effective for larger cancers.
Cold treatments
Extreme cold (cryotherapy) may be used to destroy melanoma cells in some small eye melanomas, but this treatment isn’t commonly used.
Surgery
Operations used to treat eye melanoma include procedures to remove part of the eye or a procedure to remove the entire eye. What procedure you’ll undergo depends on the size and location of your eye melanoma. Options may include:
- Surgery to remove the melanoma and a small area of healthy tissue. Surgery to remove the melanoma and a band of healthy tissue that surrounds it may be an option for treating small melanomas.
- Surgery to remove the entire eye (enucleation). Enucleation is often used for large eye tumors. It may also be used if the tumor is causing eye pain.
After the eye with melanoma is removed, an implant is inserted into the same position, and the muscles controlling movement of the eye are attached to the implant, which allows the implant to move.
After you’ve had some time to heal, an artificial eye (prosthesis) is made. The front surface of your new eye will be custom painted to match your existing eye.
