Retinoblastoma

A malignant tumor that develops in one or both eyes.  A hereditary form is caused by a missing gene that suppresses tumors.  Symptoms include unreflective white pupils, a squint, and painful red eyes.  Potentially fatal if untreated.  Treatment includes chemotherapy, freezing or stitching a radioactive disc over the tumor, or removing the affected eye or eyes.  The survival rate is more than 90% if treated early.