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What is ocular melanoma (eye melanoma)?
Ocular melanoma, also called uveal melanoma, is a rare cancer that begins in the pigment-making cells inside the eye — the same kind of cells that can cause melanoma of the skin, but here they are in the eye's middle layer (the uvea), which includes the colored iris, the ring of muscle behind it (the ciliary body), and the lining behind the retina (the choroid). It is the most common cancer that starts inside the adult eye. Because it grows out of sight, it often causes no early symptoms and may be found during a routine eye exam; when symptoms do occur, they can include blurred vision, flashes or floaters, a growing dark spot on the iris, or a change in the shape of the pupil. Unlike skin melanoma, ocular melanoma is not caused by sun exposure and is diagnosed mainly by an eye specialist's examination and imaging rather than a biopsy. The central goals of treatment are to control the tumor, preserve the eye and as much vision as possible, and reduce the chance of spread — and radiation is the leading way to do this.
The main types
Doctors group ocular melanoma (eye melanoma) by where it starts and how it behaves:
| Type | What it means, simply |
|---|---|
| Choroidal melanoma | The most common type, arising in the choroid at the back of the eye behind the retina. |
| Ciliary body melanoma | A melanoma in the ring of muscle that focuses the lens; can grow before causing symptoms. |
| Iris melanoma | A melanoma in the colored front part of the eye; often seen earlier as a changing spot and usually has a more favorable outlook. |
| Conjunctival melanoma (separate type) | A rarer melanoma of the clear surface lining the eye, which behaves more like skin melanoma and is treated differently. |
Staging, in plain terms
Ocular melanoma is staged using the TNM system, which is based mainly on the size of the Tumor — its thickness and width within the eye — along with whether it has grown into nearby structures, reached lymph Nodes (uncommon for inside-the-eye tumors), or spread (Metastasized) to distant organs, most often the liver. Larger tumors and certain genetic features of the tumor cells carry a higher risk of spread, which guides monitoring and treatment.
| TNM (size and location based) | What it generally means |
|---|---|
| Stage 1 | A small tumor confined to the eye — often treated with radiation that preserves the eye, with an excellent chance of local control. |
| Stage 2 | A medium-sized tumor confined to the eye, still very treatable with eye-preserving radiation or surgery. |
| Stage 3 | A large tumor or one that has grown into nearby structures of the eye, sometimes requiring removal of the eye if it can't be controlled otherwise. |
| Stage 4 | The cancer has spread to distant organs, most often the liver — treated with systemic medicine and liver-directed therapies, with newer immune treatments available. |
The standard of care
Ocular Melanoma (Eye Melanoma) is almost always treated by a team that may include a surgeon, a medical oncologist, and a radiation oncologist, combining therapies for the best result. The usual building blocks are:
Plaque radiation (brachytherapy)
A tiny, dish-shaped radioactive implant is stitched onto the outside of the eye over the tumor for a few days, delivering a high, focused dose that destroys the cancer while sparing most of the eye. It is the most common eye-preserving treatment.
External particle (proton) radiation
For tumors in tricky locations or near the optic nerve, a precisely aimed proton beam can treat the cancer from outside the eye while protecting nearby structures.
Surgery
Removing the eye (enucleation) is reserved for very large tumors or when the eye can't be saved or has lost useful vision; some small tumors can be removed locally.
Treatment for spread
If the cancer spreads, usually to the liver, options include newer immune-based medicines designed for uveal melanoma and liver-directed treatments, guided by a specialized team.
How radiation treatment works
Radiation uses focused high-energy beams to damage the DNA inside tumor cells so they can no longer grow and divide. In ocular melanoma, radiation is the leading treatment because it can control the tumor while preserving the eye — something surgery to remove the eye cannot do. The most common method, plaque brachytherapy, places a small radioactive disc directly on the outside of the eye over the tumor for a few days, concentrating the dose precisely where it's needed. For tumors in delicate locations, an external proton beam can deliver a sharply focused dose from outside the eye while protecting the optic nerve and central vision. Treatments are designed to maximize tumor control while sparing sight. Side effects depend on the tumor's size and location and can include changes in vision over time, dry eye, or cataract, which the eye team monitors and manages. For most patients, radiation controls the tumor and saves the eye.
The main ways radiation is delivered for ocular melanoma (eye melanoma):
Plaque brachytherapy
A custom radioactive plaque is placed directly on the eye over the tumor for several days, then removed, giving a concentrated dose to the cancer while limiting exposure to the rest of the eye.
Proton beam therapy
An external proton beam delivers a sharply focused dose that stops right at the tumor, useful for tumors near the optic nerve or fovea where preserving vision is critical.
Stereotactic radiosurgery
Highly focused external radiation in one or a few sessions is another eye-preserving option for selected tumors when plaque or proton treatment isn't ideal.
Latest studies shaping care
Care keeps improving — often toward getting the same excellent results with less burden on patients. A few developments:
Plaque radiation preserves the eye: A landmark trial showed that plaque radiation controls medium-sized eye melanomas as well as removing the eye does, allowing most patients to keep their eye without sacrificing survival.[1]
Collaborative Ocular Melanoma Study (COMS)
First effective therapy for spread to the liver: A new immune-based medicine became the first treatment shown to extend survival for metastatic uveal melanoma, a disease that previously had few options.[2]
Tebentafusp phase 3 trial, New England Journal of Medicine
Genetic testing predicts risk of spread: Analyzing the tumor's genetic profile helps identify which eye melanomas are more likely to spread, guiding how closely patients are monitored afterward.[3]
Gene-expression profiling studies, Ophthalmology
Common questions
Is ocular melanoma caused by sun exposure? Unlike melanoma of the skin, ocular melanoma is not clearly linked to sun exposure. It arises from pigment cells deep inside the eye, and its exact causes are still being studied, though certain eye colors and genetic factors may raise the risk.
Will I lose my eye? Usually not. Most ocular melanomas are treated with eye-preserving radiation — often a small radioactive plaque placed on the eye — that controls the tumor while keeping the eye. Removing the eye is reserved for very large tumors or when the eye can't be saved.
Where does ocular melanoma spread if it spreads? When it spreads, ocular melanoma most often goes to the liver. Because of this, doctors monitor the liver with imaging over time. New immune-based treatments designed for this cancer have, for the first time, been shown to help patients whose disease has spread.
References
Numbered sources for the studies cited above. Links open the primary publication on PubMed or the publisher’s site.