Radiotherapy side effects

Radiotherapy to the eye does have some side effects. You may not have all of the side effects in the list below. It depends which part of your eye is treated. During treatment, parts of your eye are protected with tiny lead shields to help prevent long term side effects.

Short term side effects

The possible short term side effects are

1. 1Loss of eyelashes
   

2. 2Increased pressure in the eye
   

3. 3Feeling tired
   

Your eyelashes should grow back after your treatment, although maybe not straightaway. Until they do grow back, some people wear false eyelashes.

Temporary swelling can cause the pressure inside your eye to rise. Until your treatment is over you have to use eye drops and possibly steroid tablets to treat this.

You are likely to feel quite tired for a few weeks after your radiotherapy. This is normal but can be frustrating. People tend to think they should have their energy back because their treatment has finished. But the radiotherapy doses can affect you for some time after treatment. So it is important to take care of yourself and rest if you feel tired.

Long term side effects

Radiotherapy to the eye sometimes causes a cataract. This is when your lens becomes misty or fogged, so that you can't see clearly. Your specialist shields your lens from the radiation beam if possible. A cataract after radiation exposure takes a while to develop, perhaps years. If you do get a cataract, you can have an operation to remove it and put in a new lens. 

Dryness of the eye can sometimes develop as a long term side effect. The gland that makes tears is shielded from the radiation to reduce this side effect. You can have eye drops to moisten your eye if dryness becomes a problem. You may need to use these drops every day to stop the covering of the eye (the cornea) from getting inflamed and sore.

Radiotherapy may cause damage to the retina (the inner lining at the back of the eye), and the optic nerve if it was in the area being treated. This damage may lead to sight loss. 

It is sometimes possible to reduce the radiation damage and hopefully improve or maintain sight by giving injections of drugs into the eye, such as bevacizumab (Avastin). This is a type of anti-VEGF drug which stops the growth of new blood vessels in the eye. Doctors usually use this type of treatment for an eye condition called macular degeneration.

If you have radiotherapy for lymphoma, you may have treatment to the brain and spinal cord as well as the eye. Radiation can cause changes to the brain tissue. This may cause problems with thinking clearly and memory, or depression.