Ocular melanoma – Cancer or tumor of the eye
Ocular melanoma (melanoma in or around the eye) is a type of cancer that develops in the cells that produce pigment. Pigment gives color to skin, hair, and eyes. Therefore, you can develop melanoma not only on your skin, but also inside or on the surface of your eye. Although it is the most common eye cancer in adults, ocular melanoma remains very rare. It usually appears in the back of the eye, under the retina, in the layer called the choroid. It often remains asymptomatic for a long time and can be difficult to detect. This is why it is important to see your ophthalmologist regularly.
What is ocular melanoma?
Ocular melanoma (or choroidal melanoma) is an eye tumor derived from the cells responsible for producing melanin, the pigment in our skin and tissues.
It most often develops in the choroid, the membrane that nourishes the retina. It is therefore visible in the fundus of the eye during a routine ophthalmological examination.
Less commonly, melanoma develops on the conjunctiva, the transparent membrane covering the surface of the eye. In this case, the patient notices a pigmented lesion that gradually increases in size.
Causes
It is not known exactly why ocular melanomas develop. However, we do know that people born with a nevus (mole) in or on the eye, as well as those with lighter-colored eyes, have a higher risk of developing ocular melanoma.
Training
Ocular melanoma occurs when the DNA of the pigment cells in the eye mutates. These mutations lead to uncontrolled cell multiplication.
The mutated cells accumulate in or on the eye and form a melanoma.
Risk factors
Certain factors increase your risk of developing ocular melanoma:
Exposure to natural sunlight or artificial light (such as that from UV tanning beds) for long periods can cause melanoma on the surface of the eye (conjunctival melanoma).
Having light-colored eyes – blue or green
An advanced age
To be of Caucasian origin
Some hereditary skin diseases, such as dysplastic nevus syndrome, cause abnormal moles.
Having abnormal skin pigmentation on the eyelids and increased pigmentation of the uvea.
Having a mole in or on the surface of the eye.
Symptoms of ocular melanoma
In its early stages, ocular melanoma causes no symptoms. Because most melanomas develop in the eye, you cannot see it and may ignore its presence.
In advanced stages, the symptoms are as follows:
A dark spot on the iris or conjunctiva.
Blurred or distorted vision.
A scotoma (blind spot) in your field of vision.
Phosphenes – Sensation of flashes of light.
A change in the shape of the pupil.
Diagnosis of ocular melanoma
The diagnosis of ocular melanoma begins with a dilated fundus examination performed by an ophthalmologist. Because ocular melanoma often causes no symptoms initially, the disease is frequently detected during a routine eye exam.
It is sometimes difficult to distinguish between a benign nevus (mole) and a malignant melanoma (cancer). In this case, the ophthalmologist may recommend further tests:
An eye ultrasound – This is a procedure in which sound waves (ultrasound) are used to create images of the eye. A small probe that sends and receives sound waves is gently placed on the surface of the eye, which has been numbed with eye drops. The echoes produce an image of the inside of the eye, allowing the size of the melanoma to be measured.
Fluorescein angiography – This test uses a dye injected into your arm, which travels to your eye. A special camera then takes pictures of the inside of your eye to see the blood supply to the lesion.
Fundus autofluorescence – This test uses a special type of camera that makes damaged areas appear as small bright spots on a photograph.
Optical coherence tomography (OCT) – This examination takes very detailed pictures of the inside of your eye.
Biopsy – case of superficial melanoma of the conjunctiva
If your ophthalmologist suspects you have conjunctival melanoma, they may perform a biopsy. This involves removing the growth from the surface of the eye. The tissue is then tested and examined in a laboratory.
Biopsies are not usually required to diagnose ocular melanoma, but they can reveal information about the tumor and its possible spread to other parts of the body.
Diagnosing melanoma is often complex. Your ophthalmologist may refer you to a specialist institute for further tests to determine if the melanoma has spread (metastasis); these tests need to be repeated regularly for many years.
Treatment of ocular melanoma
If you are diagnosed with ocular melanoma, your treatment options will vary. Treatment depends on:
The location
The size
Your general state of health
In general, treatment options fall into two categories: radiotherapy and surgery.
Radiotherapy for ocular melanoma
In radiotherapy, different types of radiation are used to burn melanoma or prevent it from developing.
The most commonly used type of radiation therapy for ocular melanoma is plate radiation therapy.
Radioactive grains are attached to a disc, called a plate, and placed directly on the wall of the eye next to the tumor.
The plaque, which resembles a tiny bottle stopper, is often made of gold.
It helps to protect surrounding tissues from damage caused by radiation directed at the tumor.
Temporary stitches hold the plate in place for four or five days, before it is removed.
Radiation therapy can also be administered by a machine (stereotaxic radiotherapy). This machine directs a thin beam of radioactive particles toward your eye. This type of radiation therapy is often carried out over several days.
Depending on the size and location of the melanoma, surgery may be recommended. The operation is often performed in conjunction with radiation therapy. It may involve removing the tumor and some of the surrounding healthy tissue in the eye.
For larger tumors, tumors that cause eye pain, and those that affect the optic nerve, the operation may involve the removal of the entire eye (enucleation).
After the eye is removed, an implant is placed in its position and attached to the eye muscles so that the implant can move. Once you have recovered from the operation, an artificial eye (prosthesis) will be fitted. It will be custom-painted to match your old eye.
Treatment of conjunctival melanoma
For melanoma located on the surface of the eye, treatment may include chemotherapy drops, surgery, freezing therapy, and radiation.
Complications
Melanoma invariably leads to the loss of the eye if left untreated. It can also metastasize and cause widespread cancer. Therefore, early treatment is crucial. However, certain long-term effects are common:
Profound vision loss
Eye pain
Metastases
Retinal detachment
Prognosis
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Treatment decisions are never made by an ophthalmologist alone. They are the result of multidisciplinary discussions between the ophthalmologist, the oncologist, and the radiation oncologist.
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You should talk to your ophthalmologist about how the treatment may affect your vision. He or she can also explain the options available to you to compensate for any potential vision loss.