Iris and conjunctival melanomas occur predominantly in individuals of Northern European descent aged older than 50 years, and both are rarely seen in other races and ethnicities.

Iris melanoma usually arises in existing nevi that are noted to have changed in size or color, or that cause pain due to increased intraocular pressure. Patients may also experience decreased vision. It is uncommon, with an incidence of 1 per million per year. Iris melanoma occurs most commonly in White individuals with a light iris color. Iris melanomas are the least aggressive melanomas of the eye compared with conjunctival, choroidal, and the ciliary body tumors.

A retrospective case series of over 1600 patients with an iris nevus who were monitored over time showed that by 15 years, growth into melanoma occurred in 8% of individuals. Risk factors for growth to melanoma, using an ABCDEF mnemonic:

• A – age young
• B – blood
• C – clock hour inferior
• D – diffuse
• E – ectropion
• F – feathery margin

The mortality rate of iris melanomas in 5 years is less than 5%.