What Are Anti-VEGF Eye Injections?

Patients ask because they have just been told they need injections into the eye, which sounds frightening, and they want to know what the medicine does and whether it really works. Many have wet macular degeneration or diabetic swelling and are anxious about both the diagnosis and the idea of a needle near the eye. They are usually reassured to learn that these injections are one of the biggest advances in retina care and often preserve vision that used to be lost.

In several retinal diseases, the body produces too much VEGF, which tells blood vessels to grow where they should not and to leak fluid and blood into the retina. When this happens in the macula, the center of vision, it causes swelling, distortion, and loss of sharp central sight. Anti-VEGF medicine works by binding and neutralizing that protein, so the leaking slows, the swelling recedes, and abnormal vessels regress.

The practical effect is that fluid in the macula dries up and vision often stabilizes or improves. Because the diseases that cause excess VEGF are usually chronic, the protein tends to build back up over time, which is why the injections are repeated rather than given once. Keeping the retina dry with regular treatment is what protects vision over the long run.

VEGF, vascular endothelial growth factor, is a signaling protein that promotes the growth of new blood vessels and increases vessel leakiness. In wet macular degeneration, abnormal vessels grow under the retina and leak; in diabetic retinopathy, high blood sugar damages vessels and drives VEGF up, causing macular edema; in retinal vein occlusion, backed-up circulation raises VEGF and causes swelling. Anti-VEGF drugs, delivered directly into the vitreous gel of the eye, counteract this at the source.

Several agents are used, including aflibercept, ranibizumab, and bevacizumab, and newer longer-acting options exist. They differ in dosing and duration but share the same basic mechanism. The procedure is done in the office: the eye is numbed and cleaned with an antiseptic, a lid speculum holds the eyelids, and the medicine is injected through the white of the eye with a very fine needle in a matter of seconds.

Most regimens begin with a series of monthly injections to dry the retina, then transition to an individualized schedule. A common approach is treat-and-extend, where the interval between injections is gradually lengthened as long as the retina stays dry on OCT imaging. This tailors treatment to each eye and reduces the total number of visits over time while protecting vision.

Anti-VEGF injections are very safe overall, and the injection itself rarely causes lasting problems. Mild redness, a small blood spot on the white of the eye, floaters, or a gritty, irritated feeling for a day or two are common and expected.

The rare but important complications to watch for are infection inside the eye (endophthalmitis), retinal detachment, and a large rise in eye pressure. Warning signs that need same-day contact with your eye doctor include increasing or severe eye pain, worsening or sudden loss of vision, a marked increase in floaters or a curtain in your vision, and growing redness or light sensitivity in the days after an injection.

The decision to use anti-VEGF injections rests on a dilated retinal exam and optical coherence tomography, or OCT, which shows fluid and swelling in the macula in fine cross-sectional detail. Fluorescein angiography, a dye test, may be used to map leaking or abnormal vessels. Before each treatment, the doctor checks vision and repeats OCT to see whether the retina is dry, whether swelling is improving, and how long the effect is lasting, which is exactly how the injection interval is set and adjusted over time. Eye pressure is monitored as well.

Anti-VEGF injection is the first-line treatment for wet macular degeneration, diabetic macular edema, and macular edema from retinal vein occlusion, and the specific agent is chosen based on the condition, response, and other factors. Injections are given in the office after numbing, and the schedule, monthly to start, then extended, is guided by OCT.

For some conditions, anti-VEGF is combined with or followed by other treatments. Steroid injections or implants are an alternative for certain cases of macular edema. Laser treatment still has a role in diabetic retinopathy and in vein occlusions with abnormal new vessels. The overall plan is individualized by a retina specialist and balances the number of injections against keeping the macula dry and vision stable.

• Do not skip or stretch out your injection appointments on your own, because the underlying disease and swelling often return when treatment lapses.
• Do not rub the eye or get untreated water in it right after an injection; follow the aftercare instructions you are given.
• Do not ignore increasing pain, worsening vision, or new floaters in the days after an injection, contact your eye doctor the same day, as these can signal infection.
• Do not assume one injection is a cure; these medicines control a chronic process and usually need to be repeated.
• Do not stop managing the root cause, such as blood sugar or blood pressure, since that drives the disease the injections are treating.

Call to be evaluated if you have new or worsening central blur, distortion, or a diagnosis of macular degeneration, diabetic swelling, or a vein occlusion, so the retina can be imaged and injections arranged if needed; patients in the Hanover area are seen at May Eye Care Center for this care. After an injection, contact the office the same day for increasing pain, worsening vision, or a burst of new floaters, and seek emergency care for sudden severe vision loss.

Anti-VEGF eye injections block the protein that makes retinal vessels leak, and they are the main, generally well-tolerated treatment for wet macular degeneration, diabetic macular edema, and vein-occlusion swelling, given on a repeating schedule to protect vision.