Children’s cancer treatment sometimes requires the use of medications or radiation that can affect the eyes. Because vision can have a significant impact on daily living, it is important for survivors who received these treatments to have their eyes checked regularly.
The eyes convert light into impulses that are transmitted to the brain, where images are perceived. The eyes are located in the area of the skull known as the orbit or eye socket. A thin layer of tissue called the conjunctiva covers and protects the eye and eyelids. Tears are produced in the lacrimal gland, located in the outer corner of the eye socket, above the eyeball. Tears flow over the eye, providing lubrication, and drain into a tiny canal at the inner corner of the eye, called the lacrimal duct.
Light enters the eye through a clear layer of tissue known as the cornea. The cornea bends and focuses the light and sends it through the opening of the eye known as the pupil. The pupil controls how much light enters the eye. Behind the pupil is the lens of the eye, which focuses the light onto the retina, the membrane along the back wall of the eye. The nerve cells in the retina change the light into electrical impulses and send them through the optic nerve to the brain, where the image is perceived.
Eye Problems Following Treatment
Cataracts: Clouding of the lens of the eye. When this happens, light cannot pass through the lens easily. Common symptoms of cataracts include painless blurring of vision, sensitivity to light and glare, double vision in one eye, poor night vision, fading or yellowing of colors, and the need for frequent changes in glasses or contact lens prescriptions.
Keratoconjunctivitis sicca: Inflammation of the cornea (the clear, outer surface of the eye) and the conjunctiva (the membrane covering the eye and eyelids) due to dryness. This occurs when radiation or graft-versus-host disease reduces the amount of tears produced by the lacrimal gland. Symptoms include pain at the surface of the eye and light sensitivity.
Other eye problems: The following eye problems are less common and are usually seen only in survivors who had radiation treatments directed at the eye or orbit:
Orbital hypoplasia: Underdevelopment of the eye and surrounding tissues, caused by radiation to the eye or to the area surrounding the eye. This can result in a small eye and orbit (orbital hypoplasia).
Lacrimal duct atrophy: Shrinking of the lacrimal duct, which drains tears from the eye. Lacrimal duct atrophy can result in problems with increased tearing.
Xerophthalmia: Scarring of the tear (lacrimal) glands following radiation to the eye or orbit. This can result in dry eyes (xerophthalmia).
Keratitis: Inflammation of the cornea (the clear, outer surface of the eye). This can cause pain at the surface of the eye and light sensitivity.
Telangiectasias: Enlargement of blood vessels in the white part of the eye. These do not usually cause any symptoms but are sometimes bothersome because of their appearance.
Retinopathy: Damage to the retina (the back surface of the eye where visual information is passed from the eye to the brain). Painless vision loss is the major symptom of retinopathy.
Optic chiasm neuropathy: Damage to the nerves that send visual information from the eye to the brain. This can result in vision loss.
Enophthalmos: Sunken eyeball within the orbit.
Symptoms of Eye Problems
Survivors should seek prompt medical evaluation for any of the following symptoms. In some cases, referral to an ophthalmologist may be needed:
- Blurry vision
- Double vision
- Blind spots
- Sensitivity to light
- Poor night vision
- Persistent irritation of surface of eye or eyelids
- Excessive tearing/watering of eyes
- Pain within the eye
- Dry eyes
What cancer therapies increase the risk of developing these eye complications?
Certain medications increase the risk of cataracts, but do not usually increase the risk of developing other eye complications. These include:
- Corticosteroids, such as prednisone and dexamethasone
Radiation therapy to the following areas is responsible for most treatment-related eye problems:
- Brain (cranial) or brain and spine (craniospinal)
- Total body irradiation (TBI)
- Radiation doses less than 30 Gy (3000 cGy/rads) increase the risk of cataracts, but do not usually increase the risk of developing other eye complications.
The risk for cataracts caused by radiation increases with:
- Radiation dose of 2 Gy (200 cGy/rads) or higher during a single treatment (fraction)
- Total radiation dose of 10 Gy (1000 cGy/rads) or higher
- TBI given as a single dose (unfractionated TBI)
- The passage of time (the longer off therapy the survivor is)
The risk for other long-term complications affecting the eye is usually associated with a radiation dose of 30 Gy (3000 cGy/rads) or more to the eye or orbit.
Other factors that may increase the risk for developing certain eye problems include:
- Chronic graft-versus-host disease following allogenic (from a donor other than the patient) bone marrow or stem cell transplant (increased risk for keratoconjunctivitis sicca)
- Diabetes mellitus (increased risk for retinopathy and optic chiasm neuropathy)
- High blood pressure (increased risk of optic chiasm neuropathy)
- Frequent exposure to sunlight (increased risk for cataracts)
Monitoring Eye Health
The chart below provides recommendations for ongoing eye monitoring:
Busulfan Corticosteroids (such as prednisone or dexamethasone)
Evaluation of vision during regular medical checkup- including visual acuity and examination for cataracts (funduscopic examination)
Yearly (if any problems are detected survivors should have an evaluation done by an ophthalmologist)
Total body irradiation (TBI)
Examination by ophthalmologist
Radiation to the brain, eye, orbit
30 Gy(3000 cGy) or higher
Examination by ophthamologist
Less than 30 Gy (3000 cGy)
Examination by ophthalmologist
Every three years, plus yearly vision and funduscopic exams during regular medical checkups
Treating Eye Problems
Cataracts: Not all cataracts need treatment. In many cases, an ophthalmologist may monitor the vision closely over many years, and will recommend treatment if and when it becomes necessary. The only treatment for cataracts is surgical removal of the lens and replacement with an artificial lens. Today, cataract surgery is a low-risk procedure that is performed on an outpatient basis and works well in restoring vision.
Orbital hypoplasia: Usually no treatment is needed. In severe cases, rebuilding of the bones around the eye may be possible.
Lacrimal duct atrophy: A surgical procedure to widen the tear drainage system can be performed if heavy tearing is a significant problem.
Xerophthalmia: Treatment of dry eye includes the frequent use of artificial tears (eye drops) or ointments to moisten the surface of the eye. In severe cases, the tear drainage system can be blocked by surgery to reduce the drainage of tears from the eye.
Keratitis and keratoconjunctivitis sicca: The frequent use of artificial tears (eye drops) or ointments to moisten the surface of the eye is recommended. Patching the affected eye during sleep may also promote healing. Keratitis caused by infection is treated with antibiotic eye drops or ointment. Rarely, surgical replacement (transplant) of the cornea is necessary.
Telangiectasias: No treatment is necessary.
Retinopathy: Retinopathy may require laser or photocoagulation (heat) treatment of the retina. Rarely, surgery to remove the eye is necessary in severe cases.
Optic chiasm neuropathy: No treatment available.
Enophthalmos: Plastic surgery can be done to build up the orbit.
Managing Impaired Vision
If impaired vision is detected, it is important to follow the recommendations of the ophthalmologist regarding treatment. If vision is not correctable, services are available in most communities to assist people with visual impairments. In addition, in the United States, services are available for people under 22 years of age through the local public school district or referral agencies (available under the Individuals with Disabilities Education Act, PL 105-17). Sometimes special accommodations, such as seating in the front of the classroom are all that is needed, but this usually requires that the parent request an Individualized Education Plan (IEP) for the child through the school district. The Americans with Disabilities Act (ADA, PL 101-336) guarantees people with visual impairment equal access to public events, spaces, and opportunities.