Retinoblastoma - (Reh-tin-oh-blast-oma) is a cancer of one or both eyes which occurs in young children. There are approximately 350 new diagnosed cases per year in the United States. Retinoblastoma affects one in every 15,000 to 30,000 live babies that are born in the United States. Retinoblastoma affects children of all races and both boys and girls.

The retinoblastoma tumor(s) originate in the retina, the light sensitive layer of the eye which enables the eye to see. When the tumors are present in one eye, it is referred to as unilateral retinoblastoma, and when it occurs in both eyes it is referred to as bilateral retinoblastoma. Most cases (75%) involve only one eye (unilateral); the rest (25%) affect both eyes (bilateral). The majority (90%) of retinoblastoma patients have no family history of the disease; only a small percentage of newly diagnosed patients have other family members with retinoblastoma (10%).