Anti-VEGF Eye Injections: What to Expect
Understanding Anti-VEGF Therapy
VEGF stands for vascular endothelial growth factor. It is a protein your body produces naturally. In healthy tissue, VEGF helps form new blood vessels when needed. In certain retinal diseases, the eye produces too much VEGF. This excess VEGF causes abnormal blood vessels to grow beneath or within the retina. These vessels are fragile and leak blood and fluid, damaging the cells responsible for central vision.
Anti-VEGF medications are biologic drugs made from living cells. Once injected into the eye, these drugs bind to VEGF molecules and block them from attaching to receptors on blood vessel cells. This action reduces leakage from existing blood vessels, prevents new abnormal vessels from forming, and can cause existing abnormal vessels to shrink. By controlling this process, anti-VEGF therapy helps preserve vision and, in many cases, can improve it.
Anti-VEGF therapy is used for several retinal conditions where excess VEGF plays a central role. The most common conditions include:
- Wet age-related macular degeneration (wet AMD), in which abnormal blood vessels grow under the macula
- Diabetic macular edema (DME), which involves swelling in the central retina caused by diabetes
- Diabetic retinopathy, where diabetes damages blood vessels throughout the retina
- Retinal vein occlusions (RVO), which occur when a vein in the retina becomes blocked
Before anti-VEGF drugs became available in 2006, treatment options for conditions like wet AMD were limited. Laser treatments could slow vision loss but rarely improved sight. The introduction of anti-VEGF therapy represented a major breakthrough. For the first time, retina specialists could stop the disease process and often help patients regain lost vision. Today, anti-VEGF injections are the standard of care for multiple retinal diseases.
Available Anti-VEGF Medications
Lucentis (ranibizumab) was the first anti-VEGF drug approved specifically for eye use in 2006. It is FDA-approved for wet AMD, DME, diabetic retinopathy, and retinal vein occlusions. Lucentis is typically given every four weeks, though some patients may be treated on an extended schedule. Several biosimilar versions of ranibizumab, including Byooviz and Cimerli, are now available.
Eylea (aflibercept) was approved in 2011 and quickly became one of the most widely used anti-VEGF agents. It is approved for wet AMD, DME, diabetic retinopathy, and retinal vein occlusions. Eylea is typically given every four to eight weeks after initial monthly loading doses. Eylea HD (high-dose aflibercept) is a newer, more concentrated formulation approved for wet AMD and DME. This higher dose may allow longer intervals between injections after the loading phase.
Avastin (bevacizumab) is FDA-approved for the treatment of certain cancers but is widely used off-label for retinal conditions. It is not FDA-approved for use in the eye. Despite this, large clinical studies have shown it to be effective for wet AMD and other retinal diseases. Many retina specialists use Avastin because of its established track record in clinical research. It is typically given every four to six weeks.
Vabysmo (faricimab) was approved in 2022 and works differently from other anti-VEGF drugs. It is a bispecific antibody that blocks two proteins involved in retinal disease: VEGF and angiopoietin-2 (Ang-2). This dual action may provide more complete disease control. Vabysmo is approved for wet AMD and DME. Some patients may go up to sixteen weeks between injections, reducing the number of office visits needed each year.
Beovu (brolucizumab) was approved in 2019 for wet AMD. It can be given every eight to twelve weeks after loading doses. However, Beovu carries a known risk of retinal vasculitis (inflammation of the blood vessels in the retina) and retinal artery occlusion (blockage of blood flow in the retina). Because of these risks, it is typically reserved for patients who have not responded well to other options. Patients receiving Beovu should be closely monitored for inflammation.
Who May Need Anti-VEGF Treatment
Advanced age is the primary risk factor for wet AMD, the most common condition treated with anti-VEGF injections. The risk increases significantly after age 60. A family history of AMD also raises a person's likelihood of developing the condition. People with a close relative who has AMD should discuss screening with their eye care provider.
Diabetes is the leading cause of diabetic retinopathy and diabetic macular edema. The longer a person has diabetes and the less controlled their blood sugar, the greater their risk. High blood pressure and cardiovascular disease also contribute to retinal vascular problems, including retinal vein occlusions. Managing these systemic conditions can help protect retinal health.
Smoking is one of the most significant modifiable risk factors for AMD. It can double or even triple the risk of developing the disease (NEI, 2023). Quitting smoking at any age can reduce this risk. A healthy diet rich in leafy greens, fish, and antioxidants may support retinal health, though diet does not replace the need for treatment once a condition develops.
Signs That May Lead to Treatment
Many retinal conditions develop slowly. Early signs may include blurred central vision, difficulty reading, and a need for brighter light. Straight lines may appear wavy or distorted, a symptom called metamorphopsia. These changes are often subtle at first and may only affect one eye, making them easy to overlook.
Some retinal conditions cause sudden symptoms that require immediate attention. A rapid increase in floaters, flashes of light, a shadow spreading across your vision, or sudden vision loss in one eye are warning signs of a serious problem. If you experience any of these symptoms, see a retina specialist or go to the emergency room immediately. Delaying care can lead to severe and irreversible vision loss.
Diagnosis and Testing
A retina specialist will begin with a comprehensive dilated eye exam. Eye drops widen the pupil, allowing the specialist to examine the retina in detail. This exam can reveal abnormal blood vessels, fluid buildup, bleeding, and other signs of retinal disease. Visual acuity testing is performed to measure how well you see at various distances.
Optical coherence tomography, or OCT, is a noninvasive imaging test that takes detailed cross-sectional pictures of the retina. It can detect fluid under or within the retinal layers, measure retinal thickness, and show structural changes at a microscopic level. OCT is one of the most important tools retina specialists use to diagnose conditions and monitor treatment response over time.
Fluorescein angiography is a test that uses a special dye to photograph blood flow in the retina. The dye is injected into a vein in the arm and travels to the eye within seconds. A camera then takes rapid photographs to identify leaking vessels, poor blood flow, and abnormal vessel growth. This helps the retina specialist plan the most appropriate treatment.
The Injection Procedure
Before the procedure, the eye is cleaned with an antiseptic solution to minimize infection risk. Numbing drops or a small injection of local anesthetic is applied to reduce discomfort. A small device called a lid speculum may keep the eyelids open. The entire preparation process typically takes a few minutes.
The injection is performed using a very fine needle inserted through the white part of the eye (the sclera) into the vitreous cavity (the gel-filled space inside the eye). The medication is delivered in a very small volume. Most patients report feeling pressure rather than sharp pain. The actual injection takes only a few seconds. The entire office visit, including preparation and a brief check afterward, usually takes about 30 minutes.
Immediately after, you may notice floaters, mild redness on the white of the eye, or a gritty sensation. These effects are normal and usually resolve within a few days. Your retina specialist may check your eye pressure before you leave. Most people can return to normal activities the same day, though you should follow specific instructions from your retina specialist.
Treatment frequency depends on the drug used and how your eye responds. Many patients start with monthly loading doses, usually three to four injections given four weeks apart. After this phase, your retina specialist may extend the interval using a treat-and-extend approach. With newer agents like Vabysmo and Eylea HD, some patients can go three to four months between injections. Individual needs vary widely.
What to Expect from Treatment
Anti-VEGF treatment improves vision in approximately one in three patients and stabilizes vision in nine out of ten patients with wet AMD (AAO, 2023). Results for DME and retinal vein occlusions are similarly encouraging. The goal of treatment is to preserve your current vision and, when possible, improve it. Not all patients will experience improvement, but most can expect their condition to stabilize with consistent treatment.
Anti-VEGF therapy requires ongoing treatment. Skipping or delaying injections can allow the disease to become active again, leading to new fluid leakage and further vision loss. Some of this vision loss may not be recoverable. Keeping all scheduled appointments is one of the most important steps you can take to protect your sight. If barriers make it difficult to keep appointments, discuss these concerns with your retina specialist.
Anti-VEGF injections have a strong safety profile. The most common side effects are minor and temporary, including mild redness, floaters, and a gritty or sore feeling. Serious complications are rare. The risk of endophthalmitis (a severe infection inside the eye) is approximately 1 in 3,500 injections based on pooled clinical data (ASRS, 2023). Though rare, endophthalmitis is a medical emergency. Seek immediate care if you develop severe eye pain, significant vision loss, increasing redness, or discharge from the eye within days of an injection.
Living with Ongoing Anti-VEGF Treatment
Because anti-VEGF therapy is a long-term commitment, finding ways to manage the schedule is important. Using a calendar, phone reminders, or asking a family member to help track appointments can make it easier to stay on track. Some patients find it helpful to coordinate injection visits with other errands.
Between appointments, you can monitor your vision using an Amsler grid. This is a simple chart with a grid of straight lines and a central dot. By looking at the grid with each eye separately, you can detect new distortion, blurriness, or missing areas. These changes may indicate the disease is becoming more active. Report any new changes promptly rather than waiting for your next scheduled visit.
Living with a chronic eye condition and undergoing regular injections can be stressful. It is normal to feel anxious before injections or worried about your vision. Talking with family, friends, or a counselor can help. Low-vision rehabilitation services and support groups are available for those who have experienced significant vision changes.
When to See a Retina Specialist
If you have been diagnosed with wet AMD, DME, diabetic retinopathy, or a retinal vein occlusion, your eye care provider may refer you to a retina specialist. Retina specialists are ophthalmologists with additional fellowship training in retinal diseases and surgery. They perform intravitreal injections and manage ongoing anti-VEGF therapy. Starting treatment promptly after diagnosis gives you the best chance of preserving your vision.
While receiving anti-VEGF injections, certain symptoms require immediate attention. Contact your retina specialist or go to the emergency room right away if you experience severe eye pain, a sudden decrease in vision, markedly increased redness, new flashes of light, a sudden increase in floaters, or a shadow over part of your vision. These could be signs of a serious complication such as endophthalmitis, retinal detachment, or retinal artery occlusion. Early treatment of these complications produces the best outcomes.
Questions and Answers
Most patients are surprised at how little discomfort there is. Numbing drops or local anesthetic are applied before the injection, and the injection itself takes only a few seconds. Patients commonly describe the sensation as brief pressure rather than sharp pain. Some soreness or mild irritation may occur afterward and typically resolves within a day or two.
For most retinal conditions treated with anti-VEGF therapy, treatment is ongoing. The underlying diseases, including wet AMD and diabetic eye disease, are chronic conditions that can reactivate if treatment stops. Some patients can extend the time between injections as their condition stabilizes. Your retina specialist will adjust your schedule based on how your eye responds.
Anti-VEGF therapy significantly reduces the risk of severe vision loss. Nine out of ten patients with wet AMD maintain stable vision with consistent treatment (AAO, 2023). However, outcomes vary and no treatment can ensure a specific result. Some patients may lose vision despite treatment, particularly if the disease was advanced before starting therapy or if injections are delayed. Consistent follow-up provides the strongest protection against vision loss.
All FDA-approved anti-VEGF drugs are effective at treating retinal conditions. They differ in molecular structure, duration in the eye, dosing intervals, and other factors. For example, Vabysmo blocks two proteins instead of one, and Eylea HD may allow longer periods between injections. Avastin is used off-label for eye conditions but has proven effective in major clinical trials. Your retina specialist will recommend the medication best suited to your condition and response.
For most patients with wet AMD, DME, or retinal vein occlusions, anti-VEGF injections are the most effective treatment available. In certain cases, laser photocoagulation or steroid implants such as Ozurdex (dexamethasone implant) may be used as alternatives or supplements. Research into longer-lasting treatments, including sustained-release implants and gene therapy, is ongoing. Your retina specialist can explain which options may be appropriate for your situation.