An intravitreal injection is a procedure in order to directly administer drug into the back of the eye, an area called the vitreous cavity

This vitreous cavity which is filled with a jelly-like fluid called the vitreous humor. The procedure is usually performed by a trained ophthalmologist in the operating theatre or special procedure room at the doctor’s office.


What are intravitreal injections used for? 

Intravitreal injections are used to treat a variety of retinal conditions with different kind of drugs:


What drugs can we administer by intravitreal injection?


The intravitreal injection procedure 

Intravitreal injections are performed in a special room or the operating theatre, often with the patient on a special surgical table.

First, the eye and eyelids are given anaesthetic drops or gel so the injection will not give any pain. Sometimes a small numbing injection may be given under the conjunctiva if necessary. 

The eye and the eyelids are then sterilised, usually using povidone-iodine, a very effective solution at killing bacteria.  An eyelid speculum will then be used in order to keep the eyelids open during the whole procedure. 

Once the eye is ready for the injection, you will be asked to look in a certain direction depending on the location of the injection while the drug is injected through the white part of the eye with a very small atraumatic needle. 


Typically, patients feel slight pressure, with little to NO pain during the procedure. After the injection, the speculum will be removed and the eye will be cleaned. The entire process takes about 15 minutes.


Safety and results 

Severe complications are very rare with these injections. The major risks are:

Sometimes there may be a small subconjunctival haemorrhage on the eye where the needle enters but this usually will be absorbed within a week or two.

Your ophthalmologist may check the intraocular pressure (IOP) which is the pressure within the eye, following the procedure. There is a temporary rise in intraocular pressure (IOP) that usually returns to normal in few minutes. The intraocular pressure (IOP) may take longer to normalize in patients with glaucoma and may need further drops to lower the intraocular pressure (IOP).


What to expect after the injection

There are usually no restrictions after the injection apart from avoiding an infection of the eye on the day of the injection. However, you should contact your ophthalmologist if you experience any complications, such as:

Sometimes after the injection, you may feel that “there is something is in your eye”—this can be a reaction to the sterilising agents (povidone-iodine). Artificial tears (preferably sterile single use minims) can be used to help with such symptoms of dryness and surface irritation.

A follow-up visit with your ophthalmologist will be scheduled depending on the condition being treated but is usually about 4 to 6 weeks after the injection.


Repeated intravitreal injections 

Intravitreal injections are a necessary tool for the retinal specialist in order to treat a variety of conditions. Their use has become more popular since the introduction of Anti-VEGF drugs in 2006. Intravitreal administration often need to be repeated in conditions such as age related macular degenearation, diabetic macular oedema, and retinal vein occlusions, since their protocol often involves injections initially per month for a period of three months. Repeat injections are usually well tolerated by the patients over several years. The need for a repeat injection is determined during the clinical examination, often with the use of diagnostic tools such as Optical Coherence tomography (OCT) and Fluorescein Angiography (FA).

Research is underway that will hopefully provide longer-acting drugs in the near future which will make the injection intervals longer.