Choroidal melanomas arise from the pigmented cells of the choroid of the eye and are not tumors that started somewhere else and spread to the eye (metastatic tumors). Melanomas are a cancer which may metastasize, that is, spread to other parts of the body. Although some choroidal melanomas are more life-threatening than others, almost all should be treated as if they were malignant.
Unlike tumors in other parts of the body, choroidal melanoma is directly visible through the pupil. Most of the time, the ophthalmologist can be nearly certain of the diagnosis from clinical appearance, photographs, and ultrasound exam. Therefore, biopsy, which is often indicated to diagnose tumors in other parts of the body, is avoided.
Some choroidal melanomas appear to remain dormant, do not grow, and may not require immediate treatment. Most enlarge slowly over time and lead to loss of vision. These tumors can spread to other parts of the body and lead eventually to death.
Treatment of choroidal melanoma is recommended when your doctors judge that, on the basis of your medical history and the findings from the eye examination, your tumor is likely to enlarge and possibly spread to other parts of your body if left untreated.
For 100 years or longer, the usual treatment for choroidal melanoma has been removal of the eye, or enucleation. During the past 10 to 15 years, radiation treatment of choroidal melanoma has been refined. Radiation, at the appropriate dose rates, is intended to eliminate growing tumor cells while causing minimal damage to normal tissue. As the cells die, the tumor shrinks, but it usually does not disappear entirely. When radioactive plaque therapy is successful, the tumor stops growing and may shrink over the course of 6 to 12 months. The patient keeps his or her own eye and, in favorable circumstances, when the tumor responds well and is located away from the most important parts of the eye, the tumor is destroyed and the patient may be able to see with the eye. Radiation almost always damages some healthy parts of the eye. Radiation damage to the blood vessels of the retina (radiation retinopathy) or to the optic nerve may cause a gradual loss of vision. In some cases, hemorrhage (bleeding) into the inner part of the eye (vitreous cavity) may occur and cause loss of vision. Radiation damage to the lens may cause a cataract, which may require removal by surgery sometime later.
Over the years, other treatments have been used for patients when appropriate. Photocoagulation using white light or laser light has been used to burn small tumors, and cryotherapy has been used to kill the tumors by freezing them. These techniques work only for very small tumors. A few patients have had eye wall resection or a related procedure to surgically remove tumors from their eyes. No treatment is available that can guarantee to destroy the tumor, to preserve vision, or to absolutely assure a normal lifespan.
For removal of the eye (enucleation surgery), the patient is admitted to the hospital and the eye is removed under general anesthesia. The enucleated eye cannot be treated or repaired and replaced in the eye socket. Instead, it is replaced with a plastic or silicone ball implant . The implant is sewn into position and the eye is allowed to heal. Three to six weeks later, a specialist who makes artificial eyes fits the patient with a prosthesis. The prosthesis is a plastic shell painted to resemble the other eye and inserted between the eyelids. When the other eye moves, the ball implant moves also, causing the prosthesis to move with the normal eye. Movement is usually less than that of the normal eye; however, the doctor and close relatives are most often the only people to notice that the patient does not have two normal eyes.
Enucleation surgery removes the tumor from the body if no spread outside the eye has occurred. Unfortunately, loss of vision for the eye removed is permanent because an entire eye cannot be transplanted. There is a reduced visual field on that side of the body when looking straight ahead, and there is loss of depth perception (stereopsis) as well. You can imagine what enucleation would be like by closing or patching one eye. Many of the skills of depth perception may be relearned with time; thousands of people have lost one eye and continued to live normal, productive lives. (You may wish to read the book A Singular View, The Art of Seeing With One Eye, by Frank B. Brady.)
Although the cosmetic results after removal of the eye and fitting of an artificial eye are usually good, the eye often does not move as well as the natural eye. There also may be some differences in the position of the eyelids when compared to the natural eye and the position of the artificial eye may look slightly abnormal. Despite these potential problems, the cosmetic appearance after enucleation is usually quite good.
Home