White pupil can appear in the eyes of both children and adults after diagnosis of retinoblastoma. This is most commonly caused by calcification of treated tumours, a developing cataract after radiotherapy, or normal optic disc reflection.
Retinoblastoma survivors should have regular eye exams and vision testing to monitor the health of treated and unaffected eyes. Close ophthalmology follow-up should detect ocular concerns before they advance to a degree that causes white eye reflex.
Calcification and Leukocoria
As retinoblastoma cells die, the tumour calcifies (hardens), taking on a chalky appearance. This can generate a white reflection in flash photographs, similar to the common early sign of retinoblastoma.
Calcification occurs during and after all eye-salvage treatments for retinoblastoma. Parents may notice the child’s white reflex becomes brighter and more clearly defined during treatment, as tumours rapidly shrink and calcify. Calcification cannot be surgically removed, and the leukocoria it generates may remain throughout life.
Cataract
The eye is like a camera, with a lens that focuses light onto the retina. Cataract is a clouding of the lens, causing vision to appear blurred, like looking through a dirty window. Cataract can appear as a white pupil when seen with the naked eye, and will make the normally red-orange, yellow or blue ‘Fundal Reflex’ appear dull or absent. In the case of partial cataract, a shadow is created in the fundal reflex.
These photos show the developing shadow over the retina, and and pale white appearance of cataract in the eye.
Cataracts can develop after some retinoblastoma treatments, particularly radiotherapy, laser therapy and intravitreal chemotherapy. They usually form within 2-3 years of treatment, but can occur at any age after therapy. Higher doses of radiotherapy cause earlier, more severe cataract, and they tend to develop faster in younger children.
Routine eye exams after treatment will usually identify a developing cataract before it causes leukocoria or impaired vision. However, surgery to remove and replace the lens may not be possible for some time and several important factors need to be considered when deciding to treat cataract after retinoblastoma.
Optic Nerve Reflex
The retina is a very complex 10-layered tissue that forms the light-sensing film inside the eye, enabling us to see. It works much like a photographic film in a regular camera. It is divided into 3 sections: the light-sensing layer with rods and cones, and the bipolar and ganglion cell layers.
The ganglion cell layer combines to form the optic nerve, which sends electrical signals to the brain. The point where these cells exit the eye is called the “optic disc”, and unlike the rest of the retina, it contains no blood vessels, and no rod or cone cells.
This healthy eye shows a reflection of light from the optic disc.
When light from the camera’s flash hits the optic disc directly, a reflection of light can occur, causing the pupil to appear white. This is called “pseudoleukocoria” and it can happen in both heathy eyes and in eyes affected by retinoblastoma, before, during and after treatment.
This reflection most often occurs when the person is looking directly at the camera, and their eye is turned about 15° towards their nose.
Leukocoria caused by retinoblastoma and pseudoleukocoria can appear identical. Pseudoleukocoria can only be confirmed after a thorough eye exam performed by an experienced ophthalmologist or other eye specialist. The eye exam will examine the fundal reflex (“red reflex”) and look for signs of eye disease.
This young girl was diagnosed with retinoblastoma and had successful eye-salvage therapy. This photo was taken after treatment. The reflections were caused by a combination of tumour calcification and optic nerve reflex.
If You See Leukocoria
Seeing leukocoria in a child’s photographs after diagnosis of retinoblastoma can be very frightening for parents. It is important to remember that beyond the first few months of life, tumour will usually be large to cause a pronounced white reflex. Tumours also tend to grow more slowly as the child ages. If your child has had a recent stable EUA, it is highly unlikely the reflex was caused by new tumour growth.
Regular eye exams are vital after eye salvage treatment to detect and treat new tumour activity early. Retinoblastoma survivors should have regular eye exams throughout life to protect their remaining vision.
If you see a white reflex in either eye of your child diagnosed with retinoblastoma, or in your own photos as a survivor, firstly, stay calm. Remind yourself that:
- new tumour activity is unlikely to be the cause when regular eye exams are being done and there is no significant change in vision; and
- leukocoria may occur due to calcification of tumours in a treated eye.
Compare the photograph of leukocoria to other photos taken around the same time. Use the PhotoRED technique to check for fundal reflex. If the pupil appears white in only one photo, while all other photos show healthy fundal reflex, the camera has most likely captured normal optic nerve. Pseudoleukocoria may also appear in several photos taken from the same angle.
We advise that you discuss concerns with your retinoblastoma specialist, and request an eye exam to confirm the eye is healthy.
