Intravitreal injections means injection into the vitreous of the eye – this may be a course of Anti-VEGF injections. Patients with several retinal conditions (as listed below) can lose their central vision when abnormal blood vessels bleed or fluid accumulates under the retina in the back of the eye.
A series of injections with anti-VEGF may be given into the back of the eye to stop blood vessels from growing and thereby controlling the fluid leakage. This treatment has been in use over the last decade and is known to be highly effective in preserving central vision in many people.
Conditions where intravitreal injection with Anti-VEGF may be used:
There are two types of AMD. About 75% of people have a form called ‘early’ or ‘dry’ AMD, which develops when there is a waste buildup under the macula. Clinically, we see the waste build up as drusen. A small proportion of patients with early AMD can progress to the vision-threatening forms of AMD called late AMD. The most common form of late AMD is ‘exudative’ or ‘wet’ AMD.
Wet AMD occurs when abnormal blood vessels grow beneath the macular which may leak fluid or cause a bleed, thereby obstructing centre vision. If untreated, patients lose their vision very quickly. Anti-VEGF therapy is particularly useful in this form of AMD. Treatment is usually over a course with a loading dose of 3 or 4 monthly injections depending on the type of Anti-VEGF used.
A less common form of late AMD called geographic atrophy is where vision is lost through the macular tissue becoming atrophic or worn out. Unfortunately, Anti-VEGF treatment cannot help this form of late AMD.
Diabetic macular oedema is an eye condition occurring in people with both type 1 and type 2 diabetes. Macular oedema refers to the swelling and thickening of the macula. DMO occurs as a result of changes in retinal blood vessels in people with diabetes.
Consistently high blood sugar levels as seen in diabetes can cause damage to blood vessels, with the first signs appearing in the smallest vessels, called capillaries.
The damaged blood vessels will leak, causing the build- up of excess fluid (oedema) and blood in the macula. This may lead to severe impairment of central vision in the affected eye. DMO may be treated with a course of Anti-VEGF therapy or steroid implant.
RVO happens when there is a block in one of the retina veins. This can happen in patients with atherosclerosis, are diabetic, hypertensive or have hypercholesterolemia or are blocked by some inflammatory conditions.
The block can occur in the main retinal vein- central retinal vein occlusion (CRVO), or in one of the branches of the main vein-branch retinal vein occlusion (BRVO). One of the known sequelae of retina vein occlusion is macular oedema which may be treated by a course of Anti-VEGF treatment or steroid implant.
Anti-VEGF therapy should not be given to patients with the following:
Anti-VEGF should be used with caution in patients who have had a heart attack or stroke in the last three months, or who have uncontrolled angina or uncontrolled high blood pressure. Latest studies have shown that the risk of Anti-VEGF to stroke or heart attack is very small, theoretical risk. There is little evidence of use in pregnancy so patients who are intending to start a family would need careful discussion.
The treatment is given in an outpatient setting in a sterilised environment. The drug is injected into your eye using a fine needle. Minimal discomfort is to be expected The entire procedure takes approximately five to seven minutes, but the injection itself is over in less than 20 seconds.
The injection is given with you lying down comfortably on the couch. Local or topical anaesthetic drops will first be applied to numb your, your eyelids and surface of the eye are cleaned to prevent infection. Your face and the area around your eye will be covered by a small surgical sheet (a drape) to keep the area sterile.
A small clip (speculum) will be used to keep the eye open . The injection site is marked with callipers and your eye is stabilised with forceps or a cotton bud. A few seconds later, the injection is given.
As with any medical procedure, there is a small risk of complications following Anti-VEGF treatment. Most complications that might occur are from the injection itself, rather than the drug. For the majority of patients, the benefit of the treatment outweighs the small risks from injection.
Some common side effects that could occur include:
During the treatment process, Ms Heng will monitor you very closely , you may be seen between 2-4 weeks following injection to determine response to treatment. Usually, non responders may be noted after the loading dose.
Ms Heng will determine your response to treatment by monitoring your vision and your reduction of fluid following injection to decide if treatment should be stopped , changed to a second line treatment or switched to alternative Anti-VEGF.
You will be able to go home shortly after the treatment. You will go home with lubricating drops which will provide some comfort after the injection. Use them as often as necessary. Many patients require a loading course of three or four injections at regular intervals of four weeks.
We usually ask that you monitor for the symptoms of complications which will include severe pain/redness or vision loss and ask that you contact our clinic urgently or attend your local AnE should this happen.
VEGF – vascular endothelial growth factor plays an active and important role in promoting growth of blood vessels and maintaining retina health. However, overproduction in various retina pathologies such as wet AMD, proliferative diabetic retinopathy, diabetic macular oedema will lead to pathologies that may cause sight impairment. Anti-VEGF medication works by binding to VEGF and preventing it from binding to their receptors, reducing the growth of new and unwanted blood vessels.
The treatment has been licensed in excess of a decade for various retina pathologies , initial and multiple phase III clinical trials across diseases such as wet AMD, diabetic macular oedema, retina vein occlusion macular oedema has shown positive results in terms of vision improvements in majority of patients treated. Real world data has shown equally positive results.
