Intravitreal injections are a common medical procedure involving the direct administration of medication into the vitreous humor, the gel-like substance that fills the eye. This method delivers drugs directly to the back of the eye, offering a targeted approach to treat various eye conditions. These injections are a standard and effective treatment for numerous retinal diseases, improving the outlook for many patients. This localized delivery ensures the medication reaches the retina in a concentrated form, maximizing its therapeutic effect while minimizing systemic side effects.
Conditions Treated by Intravitreal Injections
Intravitreal injections manage several eye conditions that impact vision by delivering medication directly to the retina. This direct approach is more effective than oral or intravenous medications, allowing for concentrated doses and minimizing systemic absorption.
Age-related Macular Degeneration (AMD)
AMD, particularly its “wet” form, involves abnormal blood vessel growth under the retina that leaks fluid or blood. Intravitreal injections, using anti-vascular endothelial growth factor (anti-VEGF) medications, inhibit this growth and reduce leakage, limiting vision loss.
Diabetic Macular Edema (DME)
DME occurs when diabetes damages retinal blood vessels, causing fluid leakage and macular swelling. Anti-VEGF injections reduce this swelling, improving or stabilizing vision.
Retinal Vein Occlusions (RVO)
RVO involves blockages in retinal veins, leading to fluid buildup and vision impairment. Anti-VEGF agents and corticosteroids reduce associated macular edema.
Other Conditions
Intravitreal injections also treat uveitis (inflammation inside the eye) and endophthalmitis (a serious inner eye infection). Corticosteroids or antibiotics are injected to reduce inflammation and combat infection. Neovascular glaucoma, characterized by abnormal blood vessel growth that increases eye pressure, can also be managed with anti-VEGF injections.
The Intravitreal Injection Procedure
The intravitreal injection procedure is performed in a doctor’s office and is quick, taking about 10 to 15 minutes. Before the injection, the eye is prepared to ensure patient comfort and prevent infection. Anesthetic eye drops or a gel are applied to numb the surface of the eyeball, so the patient feels pressure rather than pain during the injection.
The area around the eye and the eyelids are cleaned with an antiseptic solution. A small device called a speculum is used to gently hold the eyelids open, preventing blinking during the procedure. The doctor will ask the patient to look in a specific direction, ensuring the medication is injected into the appropriate area of the eye.
The medication is injected using a very fine needle, which minimizes discomfort. Patients may feel slight pressure during the injection. Immediately after, the needle is removed, and a sterile cotton swab may apply gentle pressure. The eye is then cleaned again, and antibiotic drops may be applied.
Understanding Potential Side Effects
Intravitreal injections have potential side effects, ranging from common and mild to rare and serious. Common, temporary side effects include discomfort, redness, or a gritty sensation in the eye, which typically lasts for a day or two. Patients might also notice new floaters or small bubbles in their vision immediately after the injection, which usually clear within a few days. A small red spot or subconjunctival hemorrhage at the injection site is also common but generally resolves within a week or two.
Serious complications are rare but warrant immediate medical attention. These include infection inside the eye, known as endophthalmitis, and retinal detachment, where the retina pulls away from its underlying support tissue. Other rare complications include increased intraocular pressure, bleeding inside the eye (vitreous hemorrhage), or cataract formation. Patients experiencing severe pain, significant vision decrease, increased floaters, flashing lights, or a dark “curtain” effect in their vision should contact their doctor promptly.
Preparing for and Recovering from an Injection
Proper preparation before an intravitreal injection can help ensure a smooth experience. It is advisable to arrange for transportation to and from the appointment, as vision may be temporarily blurred or sensitive to light after the procedure, making driving unsafe. Patients should avoid wearing eye makeup or contact lenses on the day of the injection to reduce the risk of introducing bacteria into the eye. It is also helpful to discuss all current medications, especially blood thinners, with the doctor before the appointment, though it is usually not necessary to stop these medications.
After the injection, following specific recovery instructions is important to promote healing and prevent complications. Patients should avoid rubbing or touching the injected eye for the rest of the day, as the numbing drops may still be active, increasing the risk of scratching the eye’s surface. Swimming and wearing contact lenses should be avoided for at least two days to prevent infection. Normal activities can typically be resumed immediately, but it is best to avoid getting water or shampoo directly into the eye for a couple of days.
Mild discomfort or a gritty sensation can be managed with over-the-counter pain relievers like paracetamol and lubricating eye drops, which may be provided or recommended by the doctor. Patients should continue any other prescribed eye drops or medications as directed. It is important to be vigilant for any signs of complications, such as increasing redness, severe pain, worsening vision, or new floaters, and to contact the eye care provider immediately if these symptoms occur.