The short answer
Retinoblastoma is a cancer that forms in the retina, the light-sensing layer at the back of the eye. It mostly affects young children and is often first noticed as a white glow in the pupil. Treatment aims to cure the cancer and, when possible, save vision.
Retinoblastoma forms in the retina, the light-sensing layer at the back of the eye.
It mainly affects young children, usually under age 5.
A common early sign is a white glow in the pupil, especially in photos with flash.
It can affect one eye or both, and some forms are inherited.
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The full explanation.
The simple version
Retinoblastoma is a cancer that forms in the retina. The retina is the light-sensing layer at the back of the eye. It is a very rare childhood cancer. It can occur in one eye or in both, and it happens most often in children younger than 2.
An early sign to know
Most children are first noticed to have a white pupil. When light shines into the eye, the pupil looks white instead of red. Parents often spot it in a flash photograph. Eyes that seem to look in different directions are the next most common sign.
Other signs can include eye pain or redness, an eye that looks larger than normal, and a cloudy look to the iris and pupil. Any of these should be checked by a doctor.
One eye or both
Retinoblastoma can affect one eye or both. Most cases are not inherited, but some are. The inherited form involves a change in a gene called RB1. Children with a family history of retinoblastoma should have their eyes checked starting at an early age.
Genetic testing can show whether a child has the inherited form. This matters. Children with it also have a higher risk of a brain tumor, and of some other cancers later in life. Families are often offered genetic counseling to talk it through.
How it is treated
Treatment depends on the size and place of the tumor. It also depends on whether one or both eyes are affected. Options include cryotherapy, which freezes the tumor, and thermotherapy, which uses laser heat. Chemotherapy and radiation are also used. In some cases the team uses high-dose chemotherapy with a stem cell rescue. Surgery to remove the eye is used when it is needed.
The goals of treatment are to cure the cancer and, when possible, preserve vision.
When to get help sooner
- Call your child's oncology team at once, day or night, if your child is having chemotherapy and their temperature reaches 100.4°F (38°C) or higher. CDC treats fever during chemotherapy as a medical emergency, because a child's infection-fighting cells can be low and infection can move within hours. If you cannot reach the team quickly, take your child to an emergency department and say on arrival that the child is on chemotherapy.
- Call 911 or go to an emergency department if your child is hard to wake or unusually floppy, is breathing fast or working hard to breathe, has a seizure, has a rash that does not fade when you press a glass against it, has a sudden severe headache with vomiting, or has a serious eye injury.
- Go to an emergency department the same day if your child cannot keep fluids down, has far fewer wet diapers or bathroom trips than usual, or is very pale, cold or mottled.
- Call the eye doctor or care team the same day if your child's eye becomes painful, very red, or swollen, if the eyelid area looks infected, or if the eye bulges.
- Book an eye exam within a day or two if you see a white glow in your child's pupil, or if the eyes start to look in different directions.
Families at the start of this can see Newly Diagnosed With Retinoblastoma. It has first-week questions about specialty care, genetic counseling, and treatment planning.
Sources
Words to know
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Common questions
What is retinoblastoma?
Retinoblastoma is a cancer that forms in the retina, the light-sensing tissue at the back of the eye. It is the most common eye cancer in children.
What is an early sign?
A common early sign is a white glow or reflection in the pupil, sometimes seen in flash photographs, instead of the usual red reflection. A child may also develop a crossed or wandering eye.
Can it affect both eyes?
Yes. Retinoblastoma can affect one eye or both. When both eyes are involved, it is usually the inherited form.
Is it inherited?
Some retinoblastoma is caused by an inherited gene change, especially when both eyes are affected. Families may be offered genetic counseling.
How is it treated?
Treatment depends on the size and location of the tumor and whether one or both eyes are affected. Options can include chemotherapy, laser or freezing treatments, radiation, and sometimes surgery to remove the eye. The goals are to cure the cancer and, when possible, save vision.
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Last updated: 2026-08-18Next planned review: 2027-07-07
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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