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Tests for Retinoblastoma

Retinoblastoma is a rare eye cancer that forms in the retina (the light-sensitive tissue at the back of the eye). It’s most common in children younger than age 5 — but in rare cases, it can develop in older children or adults.

If you notice signs of retinoblastoma in your child or you have a family history of retinoblastoma, it’s important to see your child’s doctor right away. If the tests show your child has retinoblastoma, early diagnosis and treatment can help prevent vision loss and stop the cancer from spreading.

Dilated eye exam

An eye doctor can check for retinoblastoma as part of a dilated eye exam. Your child will need to get this exam from a type of eye doctor called an ophthalmologist.

During the exam, the ophthalmologist will use eye drops to dilate (widen) your child’s pupils and numb their eye. Then they’ll place a small wire device in the eye to keep it open so they can check for retinoblastoma and other eye problems.

They can usually do this exam in the office. In some cases, they may need to give your child anesthesia (medicine that stops them from feeling pain during the exam).

Imaging tests

If your child’s doctor needs more information after the dilated exam, they may do imaging tests to help them see inside and around the eye. This may include:

  • Fundus photography. Your eye doctor may take photos of your child’s retina to see where the tumor is and what it looks like.
  • Fluorescein angiography. In this test, the doctor injects a special kind of dye into the arm. This dye then travels to the eye. The doctor uses a special camera to take pictures of the retina and find any abnormal blood vessels or fluid building up around the tumor.
  • Ultrasound. The doctor uses sound waves to take a picture of the inside of the eye. This helps them see how big the tumor is and what kind of tissue it’s made of.
  • MRI scan. The doctor may do an MRI scan to study your child’s brain and the area around the eye with tumor.

These tests are painless, but very young children may need anesthesia to keep them calm or even asleep so the doctor can get a good look at their eye.

If your child is diagnosed with retinoblastoma, the doctor may recommend other tests to check for tumors outside the eye.

Genetic testing

Children with retinoblastoma also need genetic testing to see if they have the inherited type of the disease.

The inherited type of retinoblastoma can be harder to treat. Children with the inherited type of retinoblastoma are also more likely to develop tumors in both eyes. Knowing the type of retinoblastoma your child has can help doctors find the best treatment plan for them.  

To learn more about genetic testing for retinoblastoma, you can talk to a specialist called a genetic counselor.

Last updated: February 2, 2022