Vision changes

Vision changes are changes in your ability to see. They can range from small changes, such as blurred vision, to complete loss of vision. Loss of vision may also be called sight loss.

Vision changes can be caused by cancer or cancer treatments.

Cancer can cause vision changes if it affects parts of the eye, the optic nerve or the areas of the brain related to vision. These types of cancer include:

• melanoma of the eye
• lymphoma of the eye
• metastatic cancer that spreads to the eye from another part of the body
• some head and neck cancers (nasopharyngeal cancer, nasal cavity and paranasal sinus cancer)
• brain cancers

Benign (non-cancerous) brain tumours can also affect vision.

Treatments may cause vision changes when they are given to treat eye cancer, cancers that affect areas close to the eye (such as nasal cavity and paranasal sinus cancer) or a brain tumour. Treatments that may cause vision changes are surgery and radiation therapy.

Treatments that are given for other types of cancer can still cause vision changes because the eyes are sensitive to the effects of the drugs. Treatments and drugs that may cause vision changes are:

• chemotherapy – for example, cisplatin, paclitaxel, vincristine, fluorouracil
• hormonal therapy – for example, tamoxifen (Nolvadex-D)
• targeted therapy – for example, crizotinib (Xalkori), trametinib (Mekinist), ipilimumab (Yervoy)

The side effects of cancer treatment that can cause vision changes include:

• radiation retinopathy – damage to the retina caused by radiation
• optic neuropathy – damage to the optic nerve
• glaucoma – an eye disease that damages the optic nerve
• cataract – clouding of the lens of the eye
• uveitis – inflammation in the eye

Symptoms of vision changes can vary depending on their cause and other factors. Symptoms of vision changes include:

• blurred vision
• cloudy vision
• double vision
• floaters (spots that move across your field of vision)
• sensitivity to light (called photophobia)
• trouble seeing at night (called night blindness)
• loss of peripheral (side) vision
• partial loss of vision
• total loss of vision

If symptoms get worse or don't go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.

Some changes in vision are temporary and go away when treatment is finished. Some vision changes are permanent. 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.

Your doctor will try to find the cause of your vision changes. You may need to see an ophthalmologist (a medical doctor who treats eye problems).

You may need to have the following tests:

• different types of eye exams
• a neurological exam

Your healthcare team can suggest ways to help manage your vision changes. If your symptoms are a side effect of a cancer drug that you are taking, your doctor may stop giving you the drug.

Treatments are available for some vision changes but not for others.

Your doctor may prescribe a vascular endothelial growth factor (VEGF) inhibitor (a type of growth factor inhibitor therapy) to treat radiation retinopathy or optic neuropathy. This medicine is injected into the eye.

Other medicines may be prescribed to treat glaucoma. Most of these medicines come as eye drops.

Steroids may be used to treat inflammatory eye conditions that affect your vision.

Surgery may be able to help with some vision changes. Laser surgery may be used to treat glaucoma. Cataract surgery removes the lens of your eye and replaces it with an artificial lens.

You may need to wear glasses or contact lenses to help correct your vision.

Be sure to let your healthcare team know about your vision changes. You can try the following to help you manage changes to your vision.

• 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 is easier to read.

Photophobia

• Avoid bright lights.
• Wear sunglasses when you go outside or when you move from a dark to light area.

Cataracts

• Use a bright light when reading.
• Wear glasses to improve your vision.

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, and 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 they should get better as you adjust to the changes in your vision.

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.