What is an intravitreal injection?
An intravitreal injection is an injection of a compound into a particular part of the eye called the vitreous cavity, which lies behind the lens of the eye.
Intravitreal injections are used to treat many different eye conditions. The most common are diabetic retinopathy, age-related macular degeneration, vein obstructions, neovascular glaucoma and macular edema of any cause.
An Intravitreal Injection
What different types of intravitreal injections are there?
There are three main types of intravitreal injections commonly used to treat problems within the eye, Avastin, Lucentis and Kenalog.
Avastin is an antibody that binds to all forms of the natural human protein called Vascular Endothelial Growth Factor (VEGF). This VEGF stimulates the growth of and promotes leakage from blood vessels in the eye, like the ones we see in Proliferative Diabetic Retinopathy, Vascular occlusions, Age-related macular Degeneration and Neovascular glaucoma. Avastin is the first commercially available angiogenesis inhibitor, that prevents the formation of abnormal blood vessels, therefore helping in the treatment of these conditions. Although currently not approved by FDA for use in the eye, numerous studies have demonstrated that it is a safe and effective treatment for specific eye disorders.
Side effects: minimal side-effects have been reported with the use of intravitreal Avastin. Complications that relate to all intravitreal injections include: Endophthalmitis (infection in the eye), inflammation, retinal detachment, cataract and glaucoma. However, we do not recommend you have an Avastin injection if you have had a heart attack or a stroke in the last 12 months.
Lucentis is an antibody derived from Avastin, specifically designed for use in the eye. It is a smaller molecule than Avastin and binds to VEGF-A. It is the only currently approved (by the FDA) angiogenesis inhibitor for the treatment of Wet Age-Related Macular Degeneration. Results from large phase III clinical trials ANCHOR and MARINA showed that 90% of Lucentis-treated patients stabilized vision and 40% improved vision by 3 lines on the chart.
Monthly injections are required for 3 months, and further injections may be needed depending on response. Like Avastin, and because of the risk of thrombo-embolic events, we do not recommend a Lucentis injection if you have had a heart attack or a stroke in the last 12 months. No systemic side-effects have been reported with Lucentis.
Kenalog is a long-acting synthetic steroid used in the treatment of many eye conditions, most commonly macular edema of any cause. Like Avastin its intravitreal use is Off-Lable. When injected into the eye, it improves vision by drying the macular edema. The beneficial effects last approximately 3 months, and repeated injections are sometimes required.
The most common side-effects are: glaucoma (raised intraocular pressure), cataracts, inflammation and very rarely endophthtalmitis.