An intravitreal injection is a shot of medication delivered directly into the gel-filled center of your eye, called the vitreous. It is the most frequently performed eye procedure in the world, used primarily to treat conditions that threaten vision, including age-related macular degeneration (AMD), diabetic retinopathy, and retinal vein occlusion. If your eye doctor has recommended one, here’s what to expect.
Why Medication Goes Directly Into the Eye
Your eye has a natural barrier that prevents most substances in your bloodstream from reaching the retina, the light-sensitive tissue at the back of the eye. This is useful for keeping out harmful molecules, but it also blocks medications you might swallow as a pill or receive through an IV. Injecting medication directly into the vitreous bypasses that barrier entirely, delivering a concentrated dose right where it’s needed.
Most intravitreal injections deliver a type of drug that blocks a protein called VEGF (vascular endothelial growth factor). In conditions like wet AMD and diabetic retinopathy, VEGF drives the growth of abnormal, leaky blood vessels in the retina. Those vessels leak fluid and blood, damaging the retina and causing vision loss. Anti-VEGF drugs stop that process. In some cases, steroid medications are injected instead, particularly for inflammation-related conditions like uveitis or certain types of diabetic swelling.
Conditions Treated With Intravitreal Injections
The most common reasons for intravitreal injections are:
- Wet age-related macular degeneration (AMD): abnormal blood vessels grow beneath the retina and leak fluid, distorting central vision.
- Diabetic retinopathy and diabetic macular edema: high blood sugar damages retinal blood vessels over time, causing swelling and bleeding.
- Retinal vein occlusion: a blockage in the veins draining the retina leads to fluid buildup and vision loss.
Less common indications include severe eye inflammation (uveitis), myopic degeneration in highly nearsighted people, and certain retinal infections. For most of these diseases, both eyes are often affected over time, so treatment in the second eye may eventually be needed as well.
What the Procedure Feels Like
The injection itself takes only a few seconds, and the entire office visit typically lasts under 30 minutes. Before the shot, your eye is numbed using anesthetic drops, a numbing gel, or a small anesthetic-soaked pad placed on the surface of the eye. Some doctors also use a small injection of local anesthetic under the clear membrane covering the white of the eye.
With numbing in place, most patients report mild or no pain during the injection. Studies using standardized pain scales consistently place the experience in the “mild” range for the majority of people. You may feel brief pressure or a slight sting. Many patients say the anticipation is worse than the actual shot. After the injection, it’s common to notice mild irritation, a gritty sensation, or a small red spot on the white of the eye where the needle entered. These are normal and resolve within a few days.
How Often Injections Are Needed
Chronic retinal conditions like wet AMD and diabetic macular edema typically require ongoing treatment, not just a single injection. Most treatment plans start with a “loading phase” of three or more monthly injections to get the disease under control.
After that, many doctors use a “treat and extend” approach. If imaging shows the eye is stable, the interval between injections is gradually extended by two to four weeks at a time, potentially stretching to every 12 to 16 weeks. If signs of disease activity return (fluid leaking back into the retina, for example), the interval gets shortened again until things stabilize. This strategy aims to find the longest safe gap between injections, reducing the total number of office visits while keeping the disease in check. Some patients eventually reach a point where injections can be stopped, while others need them indefinitely.
How Well the Injections Work
Anti-VEGF injections have transformed the outlook for diseases that used to cause irreversible blindness. A large study tracking patients with wet AMD found that one year after starting treatment, about 59% of eyes achieved 20/40 vision or better, which is good enough to drive in most places. Among patients who already had 20/40 vision before treatment, roughly 71% maintained it after the first year.
Over longer periods, vision does tend to decline slowly, losing about 1.5 to 2 letters per year on an eye chart. At the five-year mark, about half of treated eyes still had 20/40 vision or better. Around 14% had dropped to 20/200 or worse, which is considered legally blind. These numbers reflect the reality that treatment slows disease progression dramatically but doesn’t always halt it completely. Consistent follow-up and timely injections are the strongest predictors of good long-term outcomes.
Risks and Complications
Serious complications from intravitreal injections are rare. The most feared is endophthalmitis, a severe infection inside the eye. A 2022 analysis of more than 83,000 injections found an infection rate of 0.05%, or roughly 1 in 2,000 injections. Retinal detachment is even less common, occurring at a rate of about 1 in 7,500 injections.
Minor side effects are more frequent and almost always temporary. These include a red spot on the white of the eye from the needle, mild soreness, the sensation of floaters, and temporarily blurry vision from the numbing drops or the medication itself. A small number of patients experience a temporary increase in eye pressure immediately after the injection, which the doctor may check before you leave.
What to Watch for Afterward
If your doctor places an eye pad after the injection, you can typically remove it about two hours later. Most people can return to normal activities the same day, though your vision may be slightly blurry for several hours. Over-the-counter pain relievers like acetaminophen can handle any mild discomfort.
Certain symptoms after an injection need prompt attention. Severe eye pain that worsens rather than improves, a noticeable drop in vision, or new or increasing floaters and clouds in your vision in the days following the injection can signal a serious complication like infection or retinal detachment. These are uncommon, but catching them early makes a significant difference in outcomes.