Eye cancer. Coloured magnetic resonance imaging (MRI) scan of the left eye of a 62 year old female patient with a malignant (cancerous) melanoma (dark) of the choroid, the vascular layer. It has resulted in haemorrhagic detachment of the retina, the light sensitive membrane at the back of the eyeball. The cancer has arisen from cells that produce pigment (melanin). Melanomas are invasive cancers, and may spread to other parts of the body (metastasis). If this occurs, the prognosis is poor. If the cancer has not spread, surgical removal may effect a cure.