When you think of melanoma, you probably think of cutaneous melanoma (melanoma of the skin). However, did you know that ocular melanoma, melanoma of the eye, is the second most common form of melanoma?1
Like other melanomas, ocular melanoma (OM) begins in the melanocytes, the cells that produce melanin. OM accounts for about 4% of all melanomas, with 2,000 new cases diagnosed each year. 1
- Unlike other melanomas, OM may or may not be associated with UV light/sun exposure.1,2,3
- Many OM patients report no symptoms prior to diagnosis.4
- OM is most common in individuals with light eyes and fair skin.1
Types of ocular melanoma
There are two primary types of ocular melanoma: uveal melanoma and conjunctival melanoma.
Most OM patients (over 80%) are diagnosed with uveal melanoma. The uvea is the three-layered part of the back of the eye, made up of the choroid, iris, and ciliary body. Uveal melanoma can develop in each of layer of the uveal: 2
- Choroidal melanoma: Choroidal melanoma is the most common form of uveal melanoma, and grows beneath the retina.
- Iris Melanoma: Iris melanoma is the least common form of uveal melanoma. Iris melanoma is slow growing, does not usually spread, and has the best prognosis of all uveal melanomas.
- Ciliary Body Melanoma: Ciliary body melanomas grow more quickly and metastasizes more often than other uveal melanomas.
Compared to uveal melanoma, conjunctival melanoma is very rare. Conjunctival melanoma occurs in the mucous membrane covering the surface of the eye. Unlike most ocular melanomas (which typically spread to the liver), conjunctival melanoma most often spreads to the lungs.1
Cause of ocular melanoma
The exact cause of OM is unknown. Unlike most melanomas, there is no proven link between sun exposure and OM. Research shows that UV/sun exposure and OM may be related, but the evidence is unclear.1,2,3 According to genetics research, OM may also be related to a mutation of the BAP1 gene.1
Symptoms of ocular melanoma
In the early stages, OM may not cause any symptoms. When diagnosed with OM, many patients say that they did not notice any symptoms.4
Although rare, symptoms of OM may include4,5 :
- Dark spot on the iris or conjunctiva
- Blurred or distorted vision
- Blind spot(s) in side vision
- “Floaters”- black or grey specks that ‘float’ across field of vision
- Sensation of flashing lights
- Change in shape/size of pupil
What’s my risk?
OM is slightly more common in males than females. Additionally, your risk of OM gradually increases with age.1,2
OM is also more common in patients who have1,4
- Fair skin
- Light colored eyes
- Atypical moles
- Abnormal skin pigmentation involving the eyelids
- A mole in the eye or on the surface of the eye
- Pigmentation on the uvea
Typically, OM is not visible by looking in the mirror, and most OM patients report no symptoms prior to diagnosis. As a result, OM is usually detected during a routine eye exam4.
If your healthcare provider suspects OM during a routine eye exam, he/she may conduct a special tests to visually exam the eye. These tests can include an ophthalmoscopy (an exam of the inside and back of the eye using a small magnifying lens and light), a gonioscopy (an exam of the front part of the eye), or an ultrasound of the eye.5
Most patients do not need a biopsy to diagnosis OM.5 However, if your healthcare provider suspects conjunctival melanoma (more rare than other OM’s), he/she may perform a biopsy of the surface of the eye.4
Most OM’s can be diagnosed with one of these visual examinations of the eye. However, because approximately 50% of OM’s metastasize (spread) to other parts of the body1, your healthcare provider may also perform other tests to determine if your OM has spread4. These tests may include blood tests, a chest x-ray, CT, MRI, or abdominal ultrasound.3
OM is treated differently depending on the type, location, thickness, and size of the melanoma.5 Most often, OM is treated with radiation and surgery.4
Types of radiation treatment for OM include4,5:
- Plaque Radiation: OM is often treated with plaque radiation, a procedure when radioactive seeds are attached to a small disk (called a plaque) and placed on the wall of the eye near the tumor. The plaque will remain in place for 4-5 days with temporary stiches, before being removed by the healthcare provider.
- Machine radiation: OM can also be treated with radiation from a machine. During this treatment, a radiation beam is directed to the eye to target the melanoma. Patients typically go to radiation treatments over several days.
OM can also be treated with surgery. Depending on the size and location of the tumor, surgery can include removing only the melanoma, removing the melanoma and healthy tissue around the tumor, or removing the entire eye.3 For conjunctival melanoma, treatment can include chemotherapy eye drops, a cryotherapy (freezing) treatment, and/or radiation therapy.4
If left untreated, OM can lead to increased pressure within the eye, which can cause eye pain, blurry vision, and eye redness. Some patients with OM also experience vision loss.3
Like other forms of melanoma, OM can spread to other parts of the body. Approximately 50% of OM’s metastasize, usually between 10 and 15 years after initial diagnosis. When OM does metastasize, it most often metastasizes to the liver.1
If you notice any changes to your eyes or vision, contact your healthcare provider. To keep your eyes healthy, you should also schedule regular eye exams with your optometrist or ophthalmologist.