Retinoblastoma is an eye cancer that originates from cells of the retina. This cancer can occur in adults, but the vast majority of people who develop retinoblastoma are children. According to the Cleveland Clinic, between 200 and 300 children are diagnosed with retinoblastoma each year in the United States. Retinoblastoma may be either hereditary or non-hereditary; the hereditary form is more likely to occur in both eyes. In cases that are hereditary, there's an increased risk of a second child in a family developing retinoblastoma. As with most cancers, an earlier diagnosis gives the eye doctor a better chance to save the child’s vision in the affected eye. Because retinoblastoma occurs in young children who are not able to recognize any of the symptoms, parents should be aware of the symptoms.
White Pupil (Leukocoria)
Leukocoria (cat's eye reflex) is the most common symptom of retinoblastoma and is the symptom that parents might most likely notice first. This symptom occurs when the pupil appears white instead of red in photographs that were taken using a flash. This is caused by the light reflecting off the tumor in the back of the eye instead of the retina. There are other eye diseases that can cause leukocoria, such as congenital cataract or the infection Toxacara canis. A thorough examination--often under anesthesia due to the young age of the patient--would be able to distinguish between these diseases.
Crossed Eyes (Strabismus)
The nervous connections in the eye and brain are still developing in childhood. Any condition that affects this development can cause the condition of strabismus. Strabismus is when the eyes don't line up together appropriately. In retinoblastoma, the retina becomes detached as the tumor grows and subsequently, the vision in that eye becomes blurry. The brain stops taking visual information from that eye to avoid double vision and confusion in the brain; the visual information from both eyes is an important reason eyes move together in the same direction. This leads to the affected eye lining up and moving differently than the normal eye.
Eye Pain
For some patients, eye pain caused by glaucoma is a significant symptom of retinoblastoma. As noted in the 2005 "Shields' Textbook of Glaucoma," written by Allingham and colleagues, glaucoma is a frequent complication of retinoblastoma. The glaucoma may be caused by several mechanisms: closing of the drainage angle of the eye by new blood vessels (neovascularization), closing of the drainage angle mechanically by a large tumor mass, or blockage of the angle by inflammation. This eye would be red.
Enlargement of the Eye
Increased eye pressure or glaucoma causes the eyes of children to become larger than normal. The pressure causes the walls of the eye to stretch; this condition is called buphthalmos or cow eye. According to the Eye Cancer Network, children with both neovascular glaucoma and enlargement of the eye are at higher risk for the cancer to spread outside of the eye.
References
- Clevand Clinic: Retinoblastoma
- Eye Care America: Retinoblastoma
- Uninversity of Michigan Kellogg Eye Center: Retinoblastoma
- "Shields' Textbook of Glaucoma"; R. Rand Allingham, M. Bruce Shields, Sharon Freedman; 2005.
- Eye Cancer Network: Retinoblastoma
