What it is
The choroid is a dense layer of blood vessels and pigmented cells sandwiched between the retina and the white wall of the eye. It nourishes the outer retina. A choroidal melanoma is a malignant tumor arising from the pigment cells of that layer. It is the most common cancer to start inside the adult eye, though it remains uncommon overall — roughly six cases per million people per year. It is more frequent in people with light skin, light eyes, and a tendency to burn rather than tan.
This is a diagnosis that understandably frightens people. Two things are worth saying at the outset: most pigmented spots found inside the eye are not cancer, and for those that are, treatment today is highly effective at controlling the tumor and, in most cases, preserving the eye.
Freckles, nevi, and melanoma
A choroidal nevus is a benign pigmented spot — essentially a freckle inside the eye. They are common, found in something like one in twenty adults, and the overwhelming majority never change or cause any trouble. When one is found, the question is not usually “is this cancer?” but “does this have features that warrant closer watching?”
The features that raise concern are well established: greater thickness, fluid under the adjacent retina, symptoms, orange pigment on the surface, proximity to the optic nerve, and documented growth over time. A lesion with none of these is very likely to stay a harmless nevus. A lesion with several is treated as a melanoma until proven otherwise.
Symptoms
Small tumors typically cause nothing at all, which is why so many are found incidentally. When symptoms do occur they may include:
- Blurred vision in one eye
- A shadow, blind spot, or loss of part of the field of vision
- Flashing lights or new floaters
- Distortion of straight lines, if fluid has tracked under the macula
Pain is unusual and, when present, occurs only in advanced disease.
How we evaluate it
The evaluation is done with imaging rather than with a biopsy, and it is painless:
- Dilated examination with careful documentation of the lesion’s location, color, and borders
- Wide-field retinal photography, so that we can compare the lesion precisely against itself over time
- B-scan ultrasound, which measures the thickness of the lesion in millimeters and shows its internal characteristics — the single most useful test in distinguishing a nevus from a melanoma
- Optical coherence tomography (OCT), which detects subtle fluid under the retina that the eye alone cannot see
- Autofluorescence imaging, which highlights orange pigment and areas of retinal stress overlying the lesion
Treatment
Choroidal melanoma is treated at specialized ocular oncology centers, and we refer patients directly to one when the diagnosis is made or strongly suspected. The main options are:
- Plaque brachytherapy. A small disc containing radioactive seeds is stitched to the outside wall of the eye over the tumor for several days and then removed in a second short operation. This is the most common treatment for small and medium tumors, and it saves the eye in the great majority of cases. Large clinical trials established that survival with plaque radiation is equivalent to removing the eye.
- Proton beam or stereotactic radiotherapy, used for tumors in locations that are difficult to treat with a plaque.
- Enucleation — removal of the eye — which is reserved for very large tumors or eyes that are already blind and painful.
- Genetic testing of the tumor, often done at the time of treatment with a fine-needle sample, which gives useful information about the risk of spread and guides how closely you are monitored afterward.
Because choroidal melanoma can spread — most often to the liver — treatment is paired with a schedule of systemic surveillance imaging and blood work coordinated with a medical oncologist.
Monitoring and follow-up
For a benign-appearing nevus, follow-up usually means repeat photographs, OCT, and ultrasound at intervals — more often at first, then spaced out once stability is established. Comparing today’s images against a baseline from years ago is far more informative than any single visit, which is why we keep and archive them.
After treatment for a melanoma, we work alongside the ocular oncology team to monitor the eye locally, and to manage the effects that radiation can have on the retina and optic nerve over the following years, including intravitreal injections for radiation-related retinopathy or macular edema.
Our role
We evaluate and follow pigmented lesions inside the eye, arrange the imaging needed to characterize them, and provide clear, honest guidance about what we are seeing. When treatment is needed, we make the referral, help you get seen quickly, and stay involved in your care afterward — you do not have to manage that process alone.