What is an Intravitreal Injection?
An intravitreal injection is the term used to describe an injection of medication into the vitreous, which is the clear jelly inside the eye. An injection may be performed as a one-time treatment or may need to be repeated over the course of a few months or, in some cases even years. The response to any of the injected drugs will vary according to the patient. Some patients may benefit from the injection of more than one drug (Combination Treatment).
Common conditions that may need to be treated by Intravitreal Injection:
- Wet Age-related Macular Degeneration
- Myopic Choroidal Neovascularisation
- Proliferative Diabetic Retinopathy
- Diabetic Macular Oedema
- Macular Oedema following Branch Retinal Vein Occlusion (BRVO) or Central Retinal Vein Occlusion (CRVO)
- Any other retinal vascular condition that may cause fluid to leak or new abnormal blood vessels to grow
There are several different medications used to treat the above and your retinal surgeon, Prof Stanga, will discuss the specific treatment plan with you based on your particular condition and progression. Without treatment, your vision may continue to get worse and progress to a point where treatment may no longer help.
Types of injection
Anti-VEGF Intravitreal Injections – EYLEA® and Avastin®
Eyelea® (Aflibercept) and Avastin® (Bevacizumab) are both anti-vascular endothelial growth factor (anti-VEGF) treatments which work by blocking a chemical called vascular endothelial growth factor (VEGF). VEGF encourages the growth of abnormal blood vessels as well as vascular leakage. This chemical is produced in excess in some eye diseases, such as age-related macular degeneration (AMD), Diabetic Retinopathy and Retinal Vein Occlusion (RVO). Both injected drugs, EYLEA® and Avastin® block VEGF by trapping it between its molecular arms.
Ophthalmologists have been using Avastin® “off-label” since 2006 to treat AMD and similar conditions because research indicates that VEGF is one of the causes for the growth of the abnormal vessels that cause these conditions. Most patients who receive treatments have decreased retinal swelling and more normal-appearing macula, which often means improved vision. Avastin® also treats macular oedema in diabetic patients.
The Royal College of Ophthalmologists (UK) has campaigned since 2012 for the use of Avastin in treatment for wet AMD. The use of Avastin as an effective treatment and with positive cost benefits was supported by the National Institute for Health and Care Excellence (NICE) guidance published in January 2018.
Steroid Intravitreal Injections – Ozurdex® and Kenalog-40®
Ozurdex® is a biodegradable “pellet” or implant that provides sustained release of a steroid or anti-inflammatory called Dexamethasone. This steroid helps to decrease inflammation, leakage from retinal blood vessels, and swelling (oedema) of the macula and/or retina.
Kenalog-40® is the commercial name of Triamcinolone Acetonide injectable suspension; a steroid or anti-inflammatory. It was initially developed as an anti-inflammatory agent for intramuscular and intraarticular use only. Ophthalmologists have been successfully using Kenalog-40® “off-label” for well over 15 years to treat Macular Oedema secondary to Vein Occlusion and similar conditions because of its anti-inflammatory properties.
How do I prepare for the injection?
You should not wear make-up or apply facial creams on the day of the injection. You should make sure you thoroughly wash your face using soap on the day of the injection. You will be given antibiotic drops following the treatment, to reduce the risk of infection.
What should I expect from treatment?
On the day of your treatment, your pupils will be dilated. A large pupil allows the doctor to examine the retina (back of the eye), if necessary, before and after the injection. The medication is injected into the eye using a very fine needle. Although the surface of your eye is numb from the anaesthetic drops, you may notice slight discomfort when the needle is inserted. The procedure is conducted in the operating room to provide maximum comfort and reduce the risk of infection. The entire procedure takes approximately 20 minutes with the injection itself taking less than 20 seconds.
Once the anaesthetic wears off, you may feel as if there is something in your eye. This usually settles within a few hours. Please refrain from rubbing your eyes for 24 hours after the injection to decrease the chance of infection or injury.
What will my vision be like after the injection?
Due to the dilating drops and the treatment itself, your vision will be blurred for some hours. For this reason, we ask that patients do not drive following their treatment.
What are the risks of this treatment?
As with any medical procedure, there is a small risk of complications. Some risks are related to the injection procedure itself and others to the type of drug injected.
Serious complications are rare and injections into the eye are considered a relatively safe procedure. The most serious post-injection complication is bacterial infection or endophthalmitis, which can lead to blindness and therefore requires an urgent report of symptoms by the patient and treatment to be administered as necessary and as an emergency in the form of an antibiotic intraocular injection or vitrectomy surgery.
After intravitreal injections of anti-VEGF, there may be an increased risk of blood clots linked to heart attacks or strokes.
Steroids injected inside the eye can cause an increase in the intraocular pressure. Drops, or rarely laser treatment or surgery may be required. Steroids can also accelerate cataract formation and surgery may be required to improve vision.
Common side effects:
- Red eye (there is usually a response to the cleaning around and of the eye prior to the injection or a bleed in the white part of the eye where the injection has been done but (this will clear within a week or two)
- Sore and gritty eye (slight ache usually lasting a few hours)
- Blurred vision (usually lasting a few hours)
- Floaters (air bubbles) in your vision may be seen for a few days following treatment. Also, there could be transient swirls of fluid in your vision immediately after the injection.
- When implanted with a steroid implant, they can usually be seen as a “floater” in the peripheral vision that usually resolves as the implant reabsorbs.
- When injected with Kenalog-40®, vision may be blurred and cloudy for 7-15 days until the steroid crystals dissolve.