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Intravitreal steroid injections

Corticosteroid drugs are used increasingly in treating a number of retinal conditions by intravitreal injection. Corticosteroids have many different effects on many different processes in and around cells throughout the body. They have been used a great deal in all aspects of medicine for several decades but do have a wide range of side effects, particularly if taken in tablet form. Treatment by intravitreal injection limits any side effects to the eye and avoids many effects on the rest of the body.

Corticosteroids work mainly by reducing inflammation, which has been shown to be involved in many retinal conditions, particularly those causing macular oedema such as diabetic retinopathy, central retinal vein occlusion and post-operative macular oedema. Dr Chauhan also uses this at the end of epiretinal membrane peels to improve the rate and amount of visual recovery after surgery.

How Are Intravitreal Steroid Injections Different?

The intravitreal injections are given in exactly the same way as those for other drugs, the only difference being that the steroid injected is not a colourless fluid and is made up of hundreds of tiny specks that are initially seen as floaters; these usually settle over days to weeks.

Are There Any Differences Between Steroid And Anti-vegf Injections?

Steroid within the eye tends to last for several months before the effect wears off so repeat injections are often required but usually only once or twice a year depending on the condition being treated.

Another difference between triamcinolone and other drugs injected into the eye is in the range of possible side effects. In addition to those for anti-VEGF drugs, there are two significant ones:

  • Cataract this is a clouding of the lens within the eye that eventually causes reduced vision and requires cataract surgery. This is a highly likely side effect of intravitreal triamcinolone and may well develop within a year or two. If cataract surgery has already been done in the eye being treated cataract does not grow back and is not relevant.
  • High intraocular pressure (IOP) – depending on the dose used, this occurs in between 20 and 40% of patients. It has been argued by some that a higher dose (4mg or more) lasts longer but this is also seems to raise the IOP more on a greater number of people. It is for this reason that Dr Chauhan uses a lower dose (2mg), as this has also been shown to be equally as effective as 4mg. At the end of vitrectomy for epiretinal membranes he uses an even lower dose (1mg).

How Are Intravitreal Injections Given?

The intravitreal injection (injection straight into the vitreous of the eye) is given in a clean environment in order to reduce the risk of infection. Most patients are concerned about 4 issues:

Will it hurt?

No. You will have anaesthetic drops instilled into your eye about three times about ten minutes apart by a nurse or orthoptist. At this stage your eye would already be numb enough for a cataract operation.  The injection itself is extremely quick and you will feel a sudden and split-second feeling of pressure. Almost every patient has a “is that all there is to it”? response after their first injection.

How will I keep my eye open for the operation?

Your eye will be held open gently with the gloved fingers of the injecting doctor.

How will I keep my eye still for the injection?

You will be asked to look at a particular point on the ceiling. This will keep your eye still.

Will I be able to see the needle?

No. The injection is done from the side and you will not see it at all.

The nurses will test your vision immediately after the injection and will then apply ointment and an eye pad. You may then go home, usually about an hour and a half after entering the clinic. The eye pad should stay on, untouched, for 4 to 6 hours and should then be removed at home. You should then put the gel that you’re given in your injected eye every 1 to 2 hours until you go to sleep. When you wake up the next day, your eye should be comfortable.

You will be provided with the gel before you leave. You will also be given instructions and several contact telephone numbers in case of problems.

What Are The Risks Of Intravitreal Injections?

Before you are treated, you need to know the risks and benefits so you can make an informed decision.
Side effects are uncommon with intravitreal injections. Some are related to the injection itself, and some due to the drug itself.

Chances of injection-related risks:

  • Infection: less than 1/2000*
  • Severe bleeding into the eye: less than 1/1000*
  • Retinal detachment: less than 1/1000*
  • Persistent high pressure in the eye: less than 1/100*
  • Cataract: less than 1/1000*
  • Allergy: less than 1/1000*
  • Inflammation: less than 1/1000* (* for each injection)