What Are Intravitreal Injections?
An intravitreal injection is a brief, in-office procedure in which your retina specialist delivers medication directly into the vitreous — the gel-filled interior of your eye — through a very fine needle. The procedure typically takes only seconds, and it is one of the most commonly performed medical procedures in the United States, with approximately 3–4 million anti-VEGF injections administered each year.
The reason medication is delivered this way is simple: the retina is protected by a natural barrier that prevents pills or eye drops from reaching it at effective concentrations. Direct injection delivers the drug exactly where it’s needed — in contact with the retina — at concentrations far higher than any other route can achieve, while minimizing side effects elsewhere in your body.
There are two main types of intravitreal medications. Anti-VEGF agents block a protein called vascular endothelial growth factor (VEGF) that drives abnormal blood vessel growth and leakage in the retina. Corticosteroid agents reduce inflammation and swelling inside the eye. Your retina specialist will recommend the type best suited to your condition.
Anti-VEGF therapy has transformed retinal care. Before its development, conditions like wet macular degeneration led almost inevitably to severe vision loss. Today, treatment can stabilize and often improve vision in the majority of patients. RVC’s Dr. Steven Schwartz was among the physicians who helped pioneer anti-VEGF therapy for macular degeneration — the very treatment now used to preserve vision for millions of patients worldwide.
What Conditions Do Intravitreal Injections Treat?
- Wet Age-Related Macular Degeneration (AMD) — Anti-VEGF injections block the abnormal blood vessel growth that causes rapid central vision loss in wet AMD, the most common reason patients receive this treatment.
- Diabetic Macular Edema (DME) — Diabetes-related damage to retinal blood vessels causes fluid to accumulate in the macula; anti-VEGF injections reduce this swelling and help preserve vision.
- Diabetic Retinopathy (Proliferative) — Anti-VEGF injections cause abnormal blood vessels to regress and reduce the risk of severe complications like vitreous hemorrhage.
- Retinal Vein Occlusion (BRVO/CRVO) — When a retinal vein becomes blocked, anti-VEGF injections treat the resulting macular swelling and improve vision.
- Myopic Choroidal Neovascularization — Abnormal blood vessel growth in highly nearsighted eyes responds well to anti-VEGF therapy.
- Uveitis-Related Macular Edema — Corticosteroid implants deliver medication directly inside the eye to control chronic inflammation and swelling that hasn’t responded to other treatments.
How Intravitreal Injections Work
In healthy eyes, VEGF helps maintain normal blood vessels. In conditions like wet AMD and diabetic retinopathy, your retina overproduces VEGF, which triggers the growth of fragile, abnormal blood vessels that leak fluid and blood beneath and within the retina. This leakage damages the macula — the part of your retina responsible for sharp, central vision — and causes progressive vision loss.
Anti-VEGF medications bind to VEGF and neutralize it, stopping abnormal vessel growth and reducing leakage. Within days to weeks, existing fluid is reabsorbed, the retina recovers its normal structure, and vision stabilizes or improves. Several FDA-approved anti-VEGF medications are available, including ranibizumab (Lucentis), aflibercept (Eylea), faricimab (Vabysmo), and aflibercept 8mg (Eylea HD). Your retina specialist will choose the medication best suited to your specific condition and response.
Newer medications like faricimab target two proteins instead of one (both VEGF and angiopoietin-2), which may allow longer intervals between injections. Bevacizumab (Avastin) is also widely used off-label and has been shown to be comparably effective at a lower cost.
For conditions driven primarily by inflammation rather than VEGF — such as uveitis or certain cases of diabetic macular edema — corticosteroid implants like dexamethasone (Ozurdex) or fluocinolone acetonide (Iluvien) deliver anti-inflammatory medication inside the eye over weeks to months. These are typically reserved for cases where anti-VEGF alone has been insufficient or when inflammation is a major contributor.
What to Expect
Before Your Injection
Your first injection is usually scheduled about 1–2 weeks after your initial retinal evaluation, once imaging and a treatment plan are in place. Urgent cases can sometimes be treated the same day.
- No fasting required — eat and drink normally
- Continue all medications, including blood thinners
- Remove contact lenses at least 2 hours beforehand
- Skip eye makeup on the day of the injection
- Arrange a driver — you will not be able to drive home due to dilation and temporary blurred vision
- Plan for about 45–60 minutes total at the office, though the injection itself takes only seconds
When you arrive, we’ll check your vision, measure your eye pressure, and take imaging of your retina. Your eye will be dilated if needed.
During the Injection
Here’s what happens, step by step:
Your eye is cleaned with an antiseptic solution (povidone-iodine) to prevent infection — this is the single most important safety step. You may feel a cool, wet sensation and a slight sting that lasts a few seconds.
Numbing drops are applied to your eye, and in many cases a small amount of additional anesthetic is given at the injection site. Within a minute or two, your eye becomes profoundly numb. Patients often describe this as “the eye is there but I can’t feel it.”
A small device gently holds your eyelids open so you don’t need to worry about blinking. You’ll feel mild pressure from this but no pain.
Then the injection itself: a very fine needle (about the width of two human hairs) enters the white part of your eye from the side — you won’t see the needle because it approaches outside your line of sight. Most patients feel brief pressure lasting a few seconds, not sharp pain. You may see a flash of light or a brief swirl in your vision as the medication enters. Then the needle is removed.
The entire injection takes about 5–15 seconds. Total time from sitting down to standing up is about 2–5 minutes.
Does it hurt? In surveys, 60–70% of patients report mild discomfort (1–3 on a 10-point scale), 20–25% report moderate discomfort, and only 5–10% report significant discomfort. Most patients say afterward, “That wasn’t as bad as I expected.” Anxiety before the first injection is almost always worse than the experience itself — and subsequent injections feel easier as the fear of the unknown fades.
After the Injection
In the first few hours: Your vision will be blurry from dilation and the procedure itself. This typically clears within 30 minutes to a few hours. You may notice a red spot on the white of your eye — this is a harmless subconjunctival hemorrhage that fades in 1–3 weeks. Mild grittiness or achiness is normal and usually resolves within a day or two.
Activity: Most patients return to normal activities within 24 hours. Avoid rubbing your eye vigorously for the first day, and avoid swimming or hot tubs for 3–5 days. Reading, watching TV, and computer work are fine immediately.
When to call us right away:
- Increasing pain (not just mild discomfort — significant worsening)
- Vision getting worse beyond the initial blur
- Increasing redness with discharge
- New floaters, flashes, or a shadow across your vision
These symptoms are uncommon but could indicate a rare complication that needs prompt attention. Call us at (310) 269-8565 — we are available for urgent concerns.
Your next appointment is typically scheduled 4 weeks after your injection to assess how your eye is responding.
Risks and Side Effects
All medical procedures carry some risk, and your retina specialist will discuss the specific risks relevant to your situation before treatment.
Common side effects (expected, not dangerous):
- Red spot on the eye (subconjunctival hemorrhage) — cosmetic only, fades in 1–3 weeks
- Mild grittiness or achiness — resolves in 1–2 days
- Temporary floaters — from the medication itself; resolves in hours to days
- Brief blurry vision — from dilation and the procedure; clears within hours
Rare but serious risks:
- Eye infection (endophthalmitis) — the most serious risk, occurring in approximately 1 in 2,000 to 1 in 5,000 injections; symptoms include increasing pain, redness, and vision loss within the first week; requires immediate treatment
- Retinal tear or detachment — very rare (approximately 1 in 2,000–5,000 injections); symptoms include new flashes, floaters, or a shadow in your vision
- Vitreous hemorrhage — bleeding inside the eye; rare and usually resolves on its own
- Elevated eye pressure — more common with corticosteroid injections; monitored and managed with drops if needed
- Cataract progression — associated with corticosteroid injections, not anti-VEGF; managed with cataract surgery if needed
The risk of a serious complication from the injection is far lower than the risk of losing your vision from untreated disease. This is why anti-VEGF therapy remains the standard of care for conditions like wet AMD, diabetic macular edema, and retinal vein occlusion.
Results and Recovery
For most patients, the goal of treatment is to stabilize your vision and, when possible, improve it. The results depend on your specific condition, how early treatment begins, and how consistently you receive your injections.
For wet macular degeneration: In landmark clinical trials, approximately 95% of treated patients maintained or improved their vision, and 25–35% gained significant improvement (three or more lines on the eye chart). Starting treatment early — before significant vision loss has occurred — is one of the strongest predictors of a good outcome. Without treatment, wet AMD leads almost certainly to progressive, irreversible central vision loss.
For diabetic macular edema: Patients typically gain 2–3 lines of vision on average, with 60–70% achieving complete resolution of macular swelling. Some patients with well-controlled diabetes can eventually discontinue injections and remain stable, though others require ongoing treatment.
For retinal vein occlusion: Most patients improve significantly, with roughly 45% gaining three or more lines of vision.
Treatment is typically ongoing, not one-time. You’ll start with three monthly injections (the “loading phase”), after which your retina specialist will gradually extend the interval between treatments based on your response — a strategy called “treat-and-extend.” Many patients eventually reach intervals of 8–12 weeks or longer between injections. Newer medications like faricimab may allow even longer intervals for some patients.
For wet macular degeneration specifically, treatment is usually indefinite. The injections control the disease but do not cure it — if treatment stops, the disease typically recurs and vision declines. Think of it like blood pressure medication: you take it as long as you need it to keep the condition under control. The good news is that with consistent treatment, most patients maintain functional vision for years.
Staying on schedule with your injections is the most important thing you can do to protect your vision. If appointment frequency, transportation, or cost become barriers, talk to us — our team can help coordinate scheduling, insurance authorization, and support.
