Eye injections

Your ophthalmologist (eye doctor) might recommend a course of intravitreal (into the eye) injections as part of the treatment for your condition. 

Types of injections

We might recommend that you have a course of ranibizumab, Faricimab (Vabysmo®), or aflibercept (Eylea®).

When there are no national guidelines to tell us which medicine to use, we sometimes use bevacizumab (Avastin®). 

All of these injections work by blocking a substance called vascular endothelial growth factor (VEGF), and are known as anti-VEGF agents. VEGF causes leakage from blood vessels at the back of the eye, which causes your eye problem.

These treatments are injected directly into the vitreous (jelly in the back of your eye). This treatment is usually given to patients with: 

  • wet, age-related macular degeneration (abnormal blood vessels and leakage in the back of the eye) 
  • diabetic macular oedema (leaking at the back of the eye due to diabetes) 
  • retinal vein occlusions (blocked blood vessel at the back of the eye)

Medicine – taking an unlicensed medicine

Using bevacizumab in the eye is unlicensed, which means that the manufacturer of the medicine has not specified it can be used in this way. However, there is evidence that it works to treat this particular condition.

You can read our information about unlicensed medicines

Benefits of intravitreal injections

The injections give the best chance of stabilising your eye condition, so that your vision is less likely to get worse. Sometimes, this treatment can improve your vision.

How many injections you will need

Some eye conditions only need 1 injection, but it is more common to have a course of treatment. They are commonly given 4 to 6 weeks apart over several months, or even years. This interval can sometimes be increased further if your condition is stable.

You are likely to be monitored with vision checks and retinal scans over a long time, and might not need an injection at each visit. Your ophthalmologist will give you more information about this.

Not having treatment

You can choose not to have treatment. It is likely that without treatment, the vision in the affected eye will get worse, and might not be recoverable at all. Please speak to your consultant if you would like more information about other treatment options that might be available to you.

People who should not have the injections

You will be asked on the day if you have any allergies. Anyone who is allergic to the medicines, or to any of the ingredients of the injection, should not have the treatment. Tell the healthcare professional if you have allergies. 

Patients with active or suspected infection in the eye, or severe inflammation, should also not have the injection. Please tell the doctor if you have a sticky, or red eye on the day of the injection.

If you have had stroke or heart attack within the previous 6 months, you must tell the doctor as your treatment might have to be delayed. The risk of having a further stroke is slightly increased in this group of patients. You will continue to be monitored in the clinic and might be suitable for treatment in the future.

Having the injection

The injection is relatively straightforward and should only take a few minutes. It will be done in a specially designed treatment room.

You will sit in a reclining chair. When you arrive for your appointment you will have eye drops put in to enlarge (dilate) your pupil, and some tests. 

The health professional giving the injection will clean around your eye with an antiseptic solution to reduce the risk of infection. Please tell the nurse if you are allergic to iodine.

You will then have a plastic drape put over your eye to hold back your eyelashes. A clip will help to stop you blinking during the procedure. More drops will be put into your eye to numb the surface of the eye.

Although you might feel a slight scratch during the injection, it is rarely painful.

Immediately after the procedure, you might have the back of your eye checked with a bright light. If you have glaucoma (raised pressure within the eye), you might have your eye pressure checked before you leave the hospital.

You might have a sensation of grit in your eye when the anaesthetic drops wear off. This should settle over time.

Side effects

Like all medicines, aflibercept, bevacizumab, and ranibizumab injections into the eye can have with side effects, although not everyone will get them.

This is not a complete list of possible side effects. Speak to your eye doctor or nurse for more information, or if you have any questions.

  • You might have a slight bleed on the surface of the eyeball, called a sub-conjunctival haemorrhage. This will heal on its own in 5 to 7 days.
  • You might notice small particles or spots in your vision (floaters). These usually settle within a few days.
  • Sometimes, small air bubbles can enter the eye at the time of the injection, creating black spots which move around, creating shadows in the vision. These are nothing to worry about and will disappear in a few days.
  • Occasionally, you might have an ache in the eye, or your vision might be dimmer than usual. This might be due to raised pressure within the eye. This should settle on its own. However, if you have glaucoma, or take anti-glaucoma medicine, or the dimness does not get better, you must tell the health professional who did your injection. If the pain persists or your vision gets worse, you must return to the hospital to have your eye pressure checked.
  • Very rarely, the treatment can cause a cataract, which can lead to your vision getting worse over a few weeks. The cataract might need to be removed surgically.

After the dilating drops, you will have temporary visual blurring for about 4 hours.

Do not drive or operate machinery until the effects of the drops have worn off and your pupil size has returned to normal. Ask someone to accompany you, or drive you to and from your appointment. 

When to get help

Contact eye casualty immediately if:

  • you have severe pain for a prolonged period of time after your injection, especially if your vision becomes more blurred. You might be asked to come back to the hospital to have the eye checked in case you have a severe infection (1 in every 1,000 cases), which can lead to loss of vision
  • there is a dark shadow across your vision which gets worse. You might have might have a retinal detachment, and surgery would be needed to correct this
  • you have any pus or discharge from the eye, as this can be a sign of infection 

Phone: 020 7188 4336, Monday to Friday, 9am to 4.30pm

After the injection

It is safe to continue with work, travel or your usual activities after having injections in your eye.

You should avoid getting water in your eye, swimming, and using eye makeup for the first 5 days.

After the injection, you will be prescribed some lubricant eye drops (carbomer) which we will give you. These lubricate the eye and will help with any gritty sensation you have after the injection, and make you feel more comfortable. You can use the drops 3 or 4 times a day, for 4 days after the injection.

You can take your usual pain relief medicines to help with any discomfort. Always follow the instructions on the packet.

Use your regular eye drops as usual.

More information on support

Macular Society provide information about macular disease and local support groups.


RNIB provide information, advice and support for people with sight problems. 


Resource number: 3195/VER4
Last reviewed: April 2024 
Next review: April 2027

Trusted Information Creator. Patient Information Forum

Contact us

If you need more information about your condition or the treatment, please speak to one of the nurses or doctors in the clinic.

If you have a problem after your injection, contact eye casualty at St Thomas’ Hospital, phone: 020 7188 4336, Monday to Friday, 9am to 4.30pm.

If you cannot get through, you can phone the Nettleship Clinic, phone: 020 7188 4321 or phone: 020 7188 4307, Monday to Friday, 9am to 4.30pm. 

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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