Retinoblastoma is a rare type of cancer found in the eye. In retinoblastoma, 1 or more tumors form in the retina. The retina is a layer of light-sensitive tissue that lines the back of the eye. It converts visual images into nerve impulses in the brain that allow us to see.

Retina of the Eye
Retina of the Eye
Copyright © Nucleus Medical Media, Inc.

As with most cancers, early diagnosis and treatment lead to better outcomes.

During early stages of fetal development, fast-growing, immature cells called retinoblasts form. Later, these cells become retinal cells. In retinoblastoma, some of these cells quickly grow out of control. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The cancer may grow along the optic nerve and reach the brain, or it may travel to other parts of the body.

It is not clear exactly what causes these problems in the cells, but it is probably a combination of genetics and environment.