Eye and vision problems

The eye is a sensitive and complex organ. Certain types of cancer or cancer treatment can cause eye and vision problems that make your eyes uncomfortable or affect your ability to see. Some of these problems may go away on their own, but most of them need treatment.

Sometimes eye and vision problems happen as late effects years after having cancer treatment.

The glands above your eyes (called the tear glands or lacrimal glands) produce tears. They keep your eyes moist and comfortable, lubricating the surface whenever you blink. Tears also remove dust and debris from the eye and help prevent infection. Tears drain through very small openings in the inner corner of your eyes and travel down through the tear ducts and out the nose.

Types of eye and vision problems include:

• blepharitis – inflammation of the eyelids
• cataracts – clouding of the lens of the eye, which causes blurred, double or faded vision
• dry eye syndrome – dryness of the eyes due to insufficient tear production, which causes pain and damage to the eye tissues
• enophthalmos – sunken eyeballs in the eye sockets
• glaucoma – increased pressure in the eye, which is a very serious condition that can damage the optic nerve and cause vision loss
• lacrimal duct atrophy – shrunken lacrimal duct (tear duct) causing more tearing or watery eyes
• maculopathy – damage to the middle part of the retina causing blurred vision
• optic neuropathy – damage to the nerves that send messages from the eye to the brain, which may cause vision loss
• orbital hypoplasia – underdeveloped eye and surrounding tissue, which causes a small eye or orbit
• papillopathy – swelling of the area where the optic nerve enters the eye.
• photophobia – eyes being sensitive to light
• retinopathy – damage to the retina causing vision loss
• telangiectasias – enlarged blood vessels in the sclera (white part of the eye)
• uveitis – inflammation in the eye
• vision changes – changes in your ability to see, which can range from blurred vision to complete loss of vision (sight loss)

Eye and vision problems can be caused by some types of cancer, or they can happen during or after certain cancer treatments.

Eye and vision problems can happen when cancer affects parts of the eye, the optic nerve or the areas of the brain related to vision.

The types of cancer that most commonly cause eye and vision problems are:

• melanoma of the eye
• lymphoma of the eye
• metastatic cancer that spreads to the eye from another part of the body
• nasopharyngeal cancer
• nasal cavity and paranasal sinus cancer
• brain cancers

Non-cancerous brain tumours can also put pressure on the optic nerve and cause eye problems. They may also cause increased pressure inside the skull, fluid buildup in the brain or other brain-related problems that affect vision.

Radiation therapy destroys cancer cells using high doses of radiation. But it can also damage healthy cells and cause side effects, including eye and vision problems. Even low doses of radiation can increase the risk of some types of eye and vision problems.

Eye and vision problems can happen when radiation is given directly to:

• the eye (orbital radiation)

• the entire body (total body irradiation, or TBI)

• the brain (cranial radiation)

• the brain and spine (craniospinal radiation)

Common eye and vision problems caused by radiation therapy include:

• dry eye syndrome
• cataracts
• enophthalmos
• maculopathy
• loss of eyelashes
• photophobia
• lacrimal duct atrophy
• orbital hypoplasia (in children)
• retinopathy
• watery eyes (due to radioactive iodine for thyroid cancer)

Drug therapies for cancer are systemic, which means the drugs travel along the bloodstream to affect the entire body. Most of these drugs cannot cross the blood-brain barrier. But some can, and they may cause changes in the eye.

Most of these changes are temporary and go away when you finish your treatment. Some eye and vision problems may be permanent or occur as late effects.

Chemotherapy drugs, such as cytarabine, cisplatin, methotrexate and vincristine, can cause photophobia, cataracts and vision changes. Combining chemotherapy and radiation therapy may increase the risk for eye and vision problems.

Immunotherapy and targeted therapies may cause inflammation in the eyes. Certain drugs, such as ipilimumab (Yervoy) and nivolumab (Opdivo), can cause dry eye and swelling around the eyes. These side effects are more common among people who receive a combination of immunotherapy drugs.

Some hormone therapy drugs, such as apalutamide (Erleada) and tamoxifen, can also cause eye and vision problems. But these are typically mild problems.

Corticosteroids, such as prednisone and dexamethasone, can increase the risk for cataracts. Inhaled steroids may cause high pressure in the eye or increase the risk for glaucoma.

Children younger than 12 years of age who are treated with drugs therapies for cancer can have more serious eye and vision problems than people who are treated when they're older.

Having surgery to remove a tumour in or close to the eye can increase the risk for eye and vision problems.

Some people may experience blurred vision after having surgery with a general anesthetic.

Dry eyes are very common in people who develop chronic graft-versus-host disease (GVHD) after a stem cell transplant. People who have received an allogenic stem cell transplant and TBI have a greater risk for cataracts. Long-term treatment of GVHD with high doses of steroids may also increase the chance of developing cataracts.

Other medical conditions and lifestyle habits can increase the risk for eye and vision problems:

• Diabetes increases the risk for problems involving the retina and optic nerve.
• High blood pressure increases the risk for damage to the optic nerve.
• Frequent exposure to sunlight increases the risk for cataracts.

Symptoms can vary depending on the type of eye and vision problem. They include:

Vision changes

• being sensitive to light​
• ​blurred vision​
• cloudy vision​
• ​double vision​
• floaters (spots that move across your field of vision)​
• loss of areas of vision​
• not being able to see distant or close objects as well as you used to​
• ​poor night vision​
• ​seeing faded colours​
• ​seeing halos or rainbow-like rings around lights​
• total loss of vision
• ​trouble seeing at night

Eye changes and discomfort

• dry, itchy or burning eyes
• swelling
• the feeling that there is something in the eye
• watery eyes
• pain
• redness
• sclera that doesn't look white
• lumps or tumours on the eyelid
• a drooping eyelid
• a small eye and orbit
• a sunken eye

Other symptoms

• nausea
• headache

If you notice any of these symptoms during or after your cancer treatment, report them to your healthcare team. The sooner you tell them of any symptoms, the sooner they can suggest ways to help manage them.

An eye doctor, such as an ophthalmologist or optometrist, can check your eyes for any problems. It's important to have your eyes checked regularly, especially if you:

• had radiation therapy to the head, brain or eyes
• had TBI for a stem cell transplant
• had a tumour in or close to the eye
• have GVHD from a stem cell transplant

The doctor will try to find out the cause of any eye and vision problems with an eye exam and neurological exam.

During an eye exam, the doctor will:

• put drops in the eyes to dilate the pupils
• use an instrument that shines a narrow beam of light in the eye (called a slit-lamp exam)
• look at the inside of the eye, including the retina and the optic nerve
• take pictures of the eye to keep track of changes in the eye

An ophthalmologist can also examine the back of the eye using a magnifying lens and light.

Once your healthcare team knows the cause of your eye and vision problem, they can suggest ways to manage it. Not all eye and vision problems need to be treated right away or at all.

If your symptoms are a side effect of a cancer drug that you are taking, your doctor may stop giving you the drug.

If vision problems are permanent, you may be referred to services in the community that help people with vision impairment.

Blepharitis is mainly treated with regular cleaning of the eyelids. Your doctor may prescribe steroid eye drops to control swelling or irritation.

Cataracts are treated with surgery to remove the lens and replace it with an artificial one. If your symptoms are mild, you may not need surgery. Getting new prescription glasses may help.

Dry eye syndrome may be treated with artificial tears or an ointment to moisten the eye. If dry eye syndrome is caused by an infection, your doctor will prescribe antibiotic eye drops or ointment. In severe cases, surgery may be done to block the tear drainage system so that tears aren't drained from the eye too quickly.

Enophthalmos may be treated with plastic surgery to build up the eye socket.

Glaucoma may be treated with eye drops, medicines, laser treatment or surgery to lower the pressure in the eye.

Lacrimal duct atrophy may be managed with medicines or warm compresses to reduce swelling. If the tearing is too heavy to manage, you may need surgery to widen the tear drainage system.

Maculopathy and retinopathy may be treated by injecting a vascular endothelial growth factor (VEGF) inhibitor (a type of growth factor inhibitor therapy) into the eye, or by applying a laser or heat to the retina.

Optic neuropathy may be treated with medicines.

Orbital hypoplasia usually isn't treated. In severe cases, you may need surgery to rebuild the bones around the eye.

Papillopathy may be treated with medicines.

Photophobia may be treated using steroid eye drops. Wearing sunglasses also helps lower the amount of light your eyes are exposed to.

Telangiectasia normally doesn't need treatment.

Uveitis may be treated with steroid eye drops and medicines.

Vision changes can sometimes be corrected by wearing glasses or contact lenses.

Talk to your healthcare team to learn more about how to manage your specific eye problems.

Changes in vision can affect reading, writing, driving, your work and other aspects of your daily life. These problems usually get better as you adjust to the vision changes and learn ways to cope.

Talk to your healthcare team about your vision changes. You can try the following to help you manage the changes in everyday life:

• Use a vision aid, such as a magnifier, to help you read small print.
• Use a small audio recorder or your phone to record things you need to remember.
• Read large-print books or listen to audiobooks.
• Use a keyboard with large-print keys.
• Make the font on your computer screen and phone larger so that it's easier to read.

The Canadian National Institute for the Blind (CNIB) Foundation provides information and resources on vision loss. They can give you practical tips to help you adapt to changes to your vision. They also offer training in specialized technology and products that make living with vision loss easier. Vision loss doesn't mean that you will have a poorer quality of life or lose your independence and ability to do your normal activities. Find out more about the CNIB Foundation.

Changes to your vision or vision loss can lead to feelings of shock, anger, sadness and frustration. It takes time and patience to deal with these feelings. But, as you adjust to the changes in your vision, your feelings should improve.

For more information about dealing with changes to your self-esteem and body image, or living with an artificial eye, check out supportive care for eye cancer.

Here are some things you can do to protect your eyes and lower your risk of developing eye and vision problems:

• Wear sunglasses with UV protection.
• Use protective eyewear when playing sports, mowing the lawn or doing anything that may get particles or fumes in your eyes.
• Be careful when using hazardous chemicals at home or work.
• Avoid accidents by not playing with things that have sharp parts, and not using fireworks or sparklers.
• Have regular eye checkups to help manage potential problems early on.

Talk to your healthcare team to learn more about ways to protect your eyes.

All people who are treated for cancer need regular follow-up. Your healthcare team will develop a follow-up plan based on the type of cancer, how it was treated, and your needs.

If you develop eye and vision problems, see an eye doctor regularly.

If you have had any of the following, have an eye exam by an ophthalmologist at least once a year:

• treatment for a tumour of the eye
• radiation therapy to the eye, orbit or brain
• GVHD as a result of a stem cell transplant

If you received radioactive iodine treatment and have side effects, your healthcare team can refer you to an ophthalmologist.

If you have an artificial eye, see your ocularist (a person who makes and fits artificial eyes) for follow-up at least once a year.