An intravitreal injection is a procedure that delivers medication directly into the vitreous, the gel-like substance filling the eye. This method allows for concentrated delivery of medication to the retina and other structures at the back of the eye. By administering treatment directly to the target area, effects on the rest of the body are limited. The procedure is a standard of care for many retinal diseases and is performed in an office setting by a retina specialist.
Medical Conditions Treated by Intravitreal Injections
Intravitreal injections are used to treat a variety of retinal conditions, many of which involve the abnormal growth of or leakage from blood vessels. Conditions like wet age-related macular degeneration (AMD), diabetic retinopathy, and retinal vein occlusions are among the most common reasons for this treatment. In wet AMD, new, unhealthy blood vessels grow beneath the macula, leading to leakage of fluid and blood that can damage central vision.
Diabetic retinopathy is another condition where abnormal blood vessels can develop in the retina. This can lead to diabetic macular edema, which is swelling in the macula, or proliferative diabetic retinopathy. Similarly, a retinal vein occlusion occurs when a blood vessel in the retina becomes blocked, causing fluid to leak. In these diseases, the injected medications are designed to counteract fluid leakage and damage from unstable blood vessels.
The Injection Procedure Experience
The intravitreal injection procedure is performed in a clinical setting and is designed to maximize safety and comfort. The process begins with anesthetic eye drops or gel to numb the surface of the eye, and in some cases, a small numbing injection may also be given. Once the eye is anesthetized, the area around the eye and the eyelids are cleaned with an antiseptic solution, like povidone-iodine, to prevent infection.
To ensure the eye remains open, a small device called an eyelid speculum is used to hold the eyelids apart. Patients are often asked to look in a specific direction to position the eye correctly. The retina specialist then uses a very fine needle to deliver the medication into the vitreous cavity. The injection itself is very quick, and while some patients report feeling pressure, the actual discomfort is often less than anticipated. The entire process takes about 10 to 15 minutes.
Post-Procedure Care and Recovery
Following an intravitreal injection, it is common to experience some mild and temporary side effects. Many people report a gritty or sandy sensation in the eye, which can be soothed with lubricating eye drops. It is also normal to see floaters, which may appear as bubbles or specks in the field of vision; these are often the medication itself and will dissipate over a day or two. A small, red blood spot may appear on the white of the eye at the injection site and typically clears within a week.
While most side effects are minor, it is important to distinguish them from signs of a serious complication. Contact your retina specialist immediately if you experience significant or increasing eye pain, a noticeable decrease in vision, or signs of infection such as pus or severe redness. To minimize risks, patients are advised to avoid rubbing the eye, getting water in the eye, or swimming for a couple of days after the procedure.
Commonly Injected Medications
The medications delivered via intravitreal injection fall into two main categories, the first being anti-VEGF agents. Anti-VEGF (Vascular Endothelial Growth Factor) medications are a primary treatment for conditions involving abnormal blood vessel growth and leakage. VEGF is a protein that signals the body to create new blood vessels. Drugs like Avastin, Eylea, and Lucentis work by blocking this signal to inhibit the growth of unhealthy vessels and reduce fluid leakage. This action can help maintain or improve vision.
Corticosteroids are the other main class of medication used in intravitreal injections. These drugs, including triamcinolone and dexamethasone, are used for their anti-inflammatory properties. They work by suppressing inflammation and reducing swelling at the macula. The choice of medication depends on the specific condition being treated and the patient’s clinical situation.