How Do Anti-VEGF Injections Work?

Dr. Russel Lazarus, July 22, 2020

What is VEGF?

Vascular endothelial growth factor (VEGF) is a protein in your body that stimulates the growth of new blood vessels needed for healing— such as when the body has sustained an injury.

In certain diseases in the eye, such as wet macular degeneration (AMD), macular edema and diabetic retinopathy, VEGF encourages the growth of abnormal blood vessels underneath the retina. These abnormal blood vessels are prone to breaking, and leaking fluid and blood into the retina.

VEGF production in the eye can also cause direct damage to existing blood vessels— causing them to break, and leak fluid and blood into the retina.

The fluid that has leaked into the retina leads to swelling of the retinal cells, damage to the retina, and consequently, vision loss.

If you suspect you have VEGF contact an eye doctor near you who can diagnose and manage any eye disease you may have.

How can VEGF production be inhibited?

Since VEGF protein can be beneficial to the body, especially during times of healing, it is important to localize inhibition of the protein to the eye itself. For this reason, the anti-VEGF medications are directly injected into the eye, during a quick and relatively painless procedure.

Anti-VEGF medications stop VEGF production in order to reduce the threat of vision loss. 

What should I expect with anti-VEGF injections?

Anti-VEGF medications have been proven to stabilize vision in 90% of people, and improve vision in 30% of people.

The anti-VEGF injections are administered in your eye doctor’s office. Before the procedure, numbing eye drops will be placed into your lower eyelid to reduce any pain during administration. Once your eyes have been numbed, using a thin needle, your eye doctor will inject the anti-VEGF medication into the clear, jelly-like substance inside your eye (vitreous), through the white part of your eye (sclera)— this only takes a few seconds, and you shouldn’t feel any pain.

After the numbing agent has worn off, you may experience some soreness, or notice floaters or blurry vision— these symptoms will subside within a day or two. Most eye doctors recommended that you try to keep your eyes dry for the next few days.

Caution: Do not plan to drive on the day of your procedure. 

How often will I need anti-VEGF injections?

For the treatments to be effective, they will need to be repeated every four to six weeks for a predetermined amount of time, depending on your individual case. After that, most patients require continual or even indefinite treatments— generally up to every 12 weeks.

Is there only one type of anti-VEGF medication?

All anti-VEGF medications work to bind the VEGF with protein molecules called aptamers. Aptamers prevent the VEGF from encouraging production of any new abnormal blood vessels.

There are five different types of anti-VEGF medications. Each of these medications contain different active drugs that consist of slightly different structures.

  • Beovu uses a drug called brolucizumab
  • Avastin uses a drug called bevacizumab
  • Lucentis uses a drug called ranibizumab
  • Eylea uses a drug called aflibercept
  • Mucugen uses a drug called pegaptanib sodium

All of these medications have been proven safe and effective— but be sure to inform your eye doctor if you have had an allergic reaction to any type of medication in the past.

Caution: These medications are not safe to use during pregnancy, or if you have an internal or external eye infection. 

Contact an eye doctor near you who can diagnose and manage any eye disease you may have.

SEE RELATED: What is Diabetic Retinopathy?

Find an eye doctor near you

What are the possible complications of anti-VEGF treatments?

If you experience any of the following symptoms after your anti-VEGF procedure, consult with your eye doctor immediately:

  • Eye pain
  • Eye swelling
  • Redness that gets worse
  • Sensitivity to light
  • Vision loss

In rare cases, intraocular injections can cause infection, inflammation, increased pressure within the eye, retinal detachment, or internal eye bleeding— these conditions must be treated immediately.

If you experience any of these symptoms after your anti-VEGF contact an eye doctor near you.

Which conditions are treated with anti-VEGF medications?

Anti-VEGF injections have been proven effective in the treatment of macular conditions that cause abnormal blood vessel growth and/or leakage of fluid, such as:

  • Wet AMD
  • Myopic macular degeneration (MMD)
  • Diabetic macular edema (DME)
  • Retinal vein occlusion (RVO)


If you have been diagnosed with any type of macular disease that is affecting the health of your retina, your eye doctor may have discussed the option of anti-VEGF treatments. 

Anti-VEGF medications have been proven to reduce the progression of macular conditions and thereby decrease associated vision loss.   

LEARN MORE:  Guide to Eye Conditions

Discuss any concerns you may have about beginning anti-VEGF treatments with an eye doctor near you. The earlier you begin treatment, the greater your chances for optimal results.