MODEL RELEASED. Eye cancer, ophthalmoscope view. Intraocular lymphoma is a rare form of lymphocyte (a type of white blood cell) cancer that occurs inside the eye. It can arise alone (primary intraocular lymphoma, PIOL) or as a secondary cancer that has metastasised (spread) from elsewhere in the body. PIOL is usually revealed, as seen here, by yellow patches resulting from infiltrates leaking beneath the retina layer of the inner eye. The most common symptoms of PIOL include blurred or reduced vision that may be irreversible. Treatment is by radiotherapy and chemotherapy.