What causes ocular melanoma?

Most ocular melanomas arise in the uvea, the pigmented middle layer of the eye that includes the iris, ciliary body, and choroid. They are biologically distinct from melanoma that begins in the skin. Cell changes disrupt the controls on division and allow a tumour to form.

Lighter eye colour, certain unusual pigmented eye or skin conditions, and some inherited susceptibility can be associated with greater risk. These features do not prove what caused a particular tumour. The contribution of ultraviolet light to melanoma inside the eye is less clear than it is for skin melanoma, so a patient should not assume that sun exposure explains the diagnosis.

An eye specialist may examine the dilated eye and use ultrasound or detailed retinal imaging to define the lesion. Some tumours are observed for change, while confirmed melanoma may be treated with plaque brachytherapy, another form of radiotherapy, laser-based treatment, or surgery. The choice depends on location, size, vision, the condition of the other eye, and the person's wider health.

Keep eye and oncology appointments after diagnosis because surveillance checks the treated eye, vision, and other organs. Ask for practical help with driving, work, or home safety if treatment or the tumour reduces sight.

Ocular melanoma may present with blurred vision, flashes, floating spots, a growing dark area on the iris, or loss of part of the visual field, although it can also be found during a routine eye examination. Seek urgent eye care for sudden vision loss, a new curtain-like shadow, many new flashes or floaters, severe eye pain, or an acutely red eye with nausea; these can signal other time-sensitive eye conditions.

Ask where the lesion sits within the eye, how certain the diagnosis is, what each treatment aims to preserve, how vision could change, whether tumour testing would influence follow-up, and which eye or general symptoms should prompt an earlier appointment.