Intravitreal Injections

Various ophthalmological diseases are now being routinely treated with intravitreal injection of pharmacological substances.

The vitreous is the jelly-like substance that fills the back part of the globe of the eye. Injecting substances directly into this jelly (intravitreal injection), allows delivery of high concentrations of the drug to the area where the greatest action of the drug is required, usually the retina. It is a potent form of treatment. It is generally considered a reasonably safe treatment. However, as with any surgical procedure, it is associated with some risks, but is generally considered a reasonably safe treatment. Your ophthalmologist will discuss with you the relative risks and benefits of such a treatment and also alternative treatment.

The eye is anaesthetised with local anaesthetic drops. The procedure is performed using an aseptic technique. The eye is cleaned with a strong antiseptic, which is essential to prevent an infection. The eyelids are then held open with a small speculum (clip) and the injection is performed using a very fine, disposable needle as shown in the figure. The procedure is usually performed in the rooms.

The white of your eye where the injection went in is likely to go red, which results from a bleed of the conjunctival vessel. It is harmless and may take 1-7 days to resolve. The eye may feel gritty once the effect of the anaesthetic wears off. These effects usually last a few hours and do not require any special treatment as they will wear off by 6-12 hours. You can take a mild analgesic tablet and/or lubricating drops if the eye is extremely uncomfortable.

Care must be taken not to rub the eye immediately after the procedure, since it can result in a corneal abrasion, which is extremely painful and can take upto 24 hours to heal. Often intravitreal injections do need to be repeated, especially when treating ongoing conditions. Your doctor will be able to inform you if this is the case and what a likely course of treatment may entail.

Drugs used in relation to age-related macular degeneration, macular edema from diabetic retinopathy and vascular occlusion include Lucentis (Ranibizumab), Eyelea (Aflibercept) and Avastin (Bevacizumab). The first two drugs have been prepared for intravitreal injection, whereas Avastin is used in an “offlabel” fashion. The “off-label” use of drugs is well accepted, where appropriate in medicine. Steroids and occasionally antibiotics and anti virals are also used for intravitreal injections in certain conditions

With any surgical intervention, there is always a possibility of a serious complication, although the risk of serious complication is very rare.

• Endophthalmitis:This is a serious vision-threatening complication which results from an infection inside the eye. The incidence of endophthalmitis is1:3000 or less. Generally, such infection will respond to treatment but occasionally it does not and results in permanent loss of sight of the eye.
• Retinal Detachment:It is a rare complication with an incidence of in 1:5000 or less. Retinal detachments are usually successfully repaired with surgery but, occasionally, this can be a serious condition with the possibility of losing some or all of sight in the eye.
• Traumatic Cataract:The chance of this occurring is probably less than 1:5000. Again, it is usually treatable with surgical intervention, but not always.
• Vitreous Haemorrhage:The chance of this occurring is in the region of 1:3000 but the bleed inside the eye tends to usually resolve with time.
• Raised intraocular pressure:Intravitreal injection may cause an immediate, brief rise in the intraocular pressure, but this is usually not a problem.Patients will often experience some vitreous floaters and possibly other transient visual disturbances and, rarely, sterile inflammation in the eye requiring treatment.

You will be given written instructions on how to contact your doctor or an emergency service and what to expect after your injection, as early intervention is very important, if there is a complication.