An anti-VEGF injection is a medication delivered directly into the eye to treat conditions where abnormal blood vessels grow and leak fluid into the retina, threatening vision. These injections are the standard treatment for wet age-related macular degeneration (AMD), diabetic retinopathy, and several other retinal diseases. The name refers to vascular endothelial growth factor (VEGF), a protein the drugs are designed to block.
How Anti-VEGF Injections Work
Your body naturally produces VEGF proteins to grow new blood vessels, which is useful during wound healing and normal development. But in certain eye diseases, the retina becomes starved of oxygen, often because existing blood vessels are blocked or damaged. In response, the eye ramps up VEGF production, triggering the growth of fragile new blood vessels. These abnormal vessels leak blood and fluid into the retina, causing swelling, scarring, and vision loss.
Anti-VEGF drugs work by binding to VEGF molecules inside the eye, essentially neutralizing them before they can trigger new vessel growth or further leakage. With the signal blocked, existing abnormal vessels can shrink and stop leaking, fluid buildup in the retina decreases, and vision often stabilizes or improves. The medication is injected directly into the vitreous (the gel-like substance filling the eye) so it reaches the retina at high concentration without affecting the rest of the body in a meaningful way.
Conditions These Injections Treat
Anti-VEGF injections are used for several retinal conditions that share a common problem: abnormal blood vessel activity damaging the retina. The most common include:
- Wet (neovascular) AMD: The leading reason these drugs were developed. Abnormal vessels grow beneath the macula, the part of the retina responsible for sharp central vision.
- Diabetic macular edema (DME): Diabetes damages retinal blood vessels, causing them to leak fluid into the macula.
- Diabetic retinopathy: More broadly, the retinal damage from diabetes that can progress to vision-threatening stages.
- Retinal vein occlusion: A blockage in the veins draining the retina leads to fluid buildup and swelling.
- Ocular histoplasmosis syndrome: A fungal infection that can later cause abnormal vessel growth in the eye.
Available Medications
Several anti-VEGF drugs are currently used, and they differ in cost, how often they need to be given, and which VEGF targets they block. The FDA-approved options for intravitreal injection include ranibizumab, aflibercept, brolucizumab, and faricimab. Bevacizumab, originally developed as a cancer drug, is widely used off-label for eye conditions at a significantly lower cost than the approved alternatives. It is not FDA-approved for treating wet AMD, but clinicians frequently prescribe it because large studies have shown comparable results for many patients.
Faricimab, approved in 2022, takes a somewhat different approach. It targets two proteins instead of one, blocking both VEGF and a second molecule called angiopoietin-2 that also contributes to blood vessel instability. This dual action may help some patients go longer between injections.
A newer high-dose formulation of aflibercept (marketed as EYLEA HD) delivers four times the standard dose. In clinical trials, patients receiving this higher dose needed fewer injections over the first year, around 5 to 6 shots compared to about 7 to 8 with the standard dose, while achieving equivalent vision improvements for both wet AMD and diabetic macular edema.
What the Injection Feels Like
The idea of a needle in the eye understandably causes anxiety, but the procedure is quick and typically less painful than people expect. The entire process takes only a few minutes. Your eye is numbed with anesthetic drops, then cleaned with an antiseptic solution (povidone-iodine) to minimize infection risk. A small device called a speculum holds your eyelids open so you don’t need to worry about blinking.
You’ll be asked to look away from the injection site. The needle enters through the white part of the eye, about 3.5 millimeters behind the colored part, into the vitreous gel. Most patients feel pressure rather than sharp pain. Studies comparing different numbing methods, including drops, gels, and deeper local anesthesia, have found no significant difference in pain levels, meaning the simple approach of anesthetic drops works well for most people.
Afterward, you may notice floaters, mild redness at the injection site, or a slightly gritty feeling. These are normal and typically resolve within a day or two. Some people see small dark spots in their vision from the medication itself as it disperses, which also clears on its own. You can generally return to normal activities the same day, though your eye doctor will provide specific guidance based on your situation.
Treatment Schedules
Anti-VEGF therapy is not a one-time treatment. These conditions are chronic, and most patients need repeated injections over months or years. The schedule depends on which drug is used and how your eye responds, but three main approaches exist.
The original approach is fixed monthly injections, which formed the basis of the pivotal clinical trials. This produces excellent results but requires frequent office visits. A second approach, sometimes called “as needed,” involves three monthly loading doses followed by monitoring visits where you receive another injection only if signs of disease activity return. The third and increasingly popular method is “treat and extend.” You receive monthly injections until the disease is controlled, then your doctor gradually stretches the interval between injections, pushing it out to every 8, 12, or even 16 weeks as long as the retina stays stable. If signs of activity return, the interval shortens again.
With newer formulations like high-dose aflibercept, many patients can maintain results with injections every 12 to 16 weeks after the initial loading phase, reducing the treatment burden considerably.
How Well They Work
Anti-VEGF injections transformed the treatment of wet AMD and diabetic eye disease. Before these drugs existed, most patients with wet AMD faced progressive, irreversible vision loss. Now the majority can maintain or improve their vision, at least in the early years of treatment.
Results tend to be strongest in the first year or two. Vision typically improves after the initial loading doses as retinal fluid clears. Long-term data tells a more nuanced story. One real-world study tracked patients with wet AMD over eight years of as-needed treatment. Vision improved from a baseline of about 61 letters on a standard eye chart to 70 letters after the initial loading phase, but gradually declined to 55 letters by year eight. At the eight-year mark, 47% of eyes still had stable or improved vision compared to where they started. Patients in that study received an average of about 32 injections over the full eight years, tapering from six injections in the first year to three in the eighth.
These numbers reflect real-world treatment, where patients sometimes miss appointments or receive fewer injections than ideal. Consistent treatment tends to produce better outcomes.
Risks and Side Effects
The most common side effects are mild: temporary redness, floaters, and eye irritation that resolve quickly. The most serious risk is endophthalmitis, an infection inside the eye that can threaten vision. This is rare. Large-scale data shows the rate has declined over time as injection techniques have improved, dropping from about 0.20% of procedures in 2000 to roughly 0.05% in 2022, or about 1 in 2,000 injections. The careful antiseptic protocol used before each injection is specifically designed to minimize this risk.
Other uncommon complications include increased eye pressure, inflammation inside the eye, and in very rare cases, retinal detachment. Because these injections are repeated many times over years of treatment, cumulative exposure to these small risks is something your eye doctor monitors at each visit. Any sudden vision loss, increasing pain, or sensitivity to light after an injection warrants prompt attention.