Retina Injection Therapy (Anti-VEGF)

What are Anti-VEGF Agents

Anti-Vascular endothelial Growth Factor (anti-VEGF injection therapy) refers to a group of medications that block the activity of VEGF, thereby mitigating its abnormal effects on ocular blood vessels.

These agents work at a molecular level by binding to VEGF proteins, preventing them from activating receptors that stimulate abnormal vessel growth. Each agent has a distinct molecular structure and mechanism, which influences its clinical dose, duration of action, and suitability for specific retinal conditions.

Clinical studies and ophthalmology experts, including guidelines from the American Academy of Ophthalmology, support the use of anti-VEGF agents as a first-line treatment for several sight-threatening retinal diseases, with strong evidence backing their efficacy and safety profiles.

Key Differences Between Anti-VEGF Agents

Bevacizumab

Bevacizumab (Avastin) is a full monoclonal antibody originally approved for colorectal cancer that has been widely used off-label for retinal conditions. A pivotal clinical study the CATT (Comparison of Age-related macular degeneration Treatment Trials) demonstrated that bevacizumab was non-inferior to ranibizumab in visual acuity outcomes for wet AMD, establishing its role in clinical practice.

Ranibizumab

Ranibizumab (Lucentis) is an antibody fragment specifically designed for intravitreal use. It has better retinal penetration and higher affinity for VEGF-A compared to bevacizumab. It is FDA-approved for wet AMD, diabetic macular edema, and retinal vein occlusion.

Aflibercept

Aflibercept (Eylea) is a fusion protein that acts as a VEGF trap, binding to multiple VEGF family members, including PIGF. The VIEW 1 and VIEW 2 international clinical trials demonstrated that aflibercept dosed every 8 weeks was equivalent in efficacy to monthly ranibizumab for wet AMD, supporting its extended dosing interval after initial loading regimen.

Brolucizumab

Brolucizumab (Beovu) is the smallest of the anti-VEGF molecules (single-chain antibody, 26 kDa), allowing high molar dosing in small volumes. The HAWK and HARRIER phase 3 trials showed non-inferiority to aflibercept, with a significant proportion of patients maintained on every 12-week dosing interval after initial loading regimen, demonstrating a meaningful advantage for treatment burden reduction.

How have anti VEGF treatment influenced the management of various eye conditions

Anti VEGF agents when administered under appropriate conditions act at molecular level countering the action of VEGF and thereby reducing the morbidity.

Many diseases which were considered untreatable earlier like age related macular degeneration are rendered treatable, enabling patients maintain quality vision and subsequent improvement in quality of life

Ocular manifestation of systemic diseases with diabetes hypertension are also now treated with anti VEGF agents, with quality vision being restored and maintained.

The Impact of Anti-VEGF Treatment on Eye Disease Management

Anti-VEGF agents have transformed the management of various eye conditions. When administered under appropriate conditions, they act at the molecular level, counteracting VEGF and thereby reducing morbidity and preventing irreversible vision loss.

Many diseases previously considered untreatable, such as wet age-related macular degeneration, are now manageable, enabling patients to maintain good vision and experience meaningful improvements in quality of life. Anti-VEGF therapy has revolutionized retinal care by shifting the treatment paradigm from reactive to proactive vision preservation.

Ocular manifestations of systemic diseases like diabetes are also now effectively treated with anti-VEGF agents, with quality vision being restored and maintained.

Conditions Treated by Anti-VEGF Agents and Their Benefits

Anti-VEGF therapy for diabetic macular edema

has shown remarkable outcomes in preserving and improving central vision, while anti-VEGF injections for retinal vein occlusion have significantly reduced the rate of severe visual impairment in affected patients.

How Do I Choose the Type of Anti-VEGF Agent

The doctor examining you will prescribe the most appropriate agent based on your specific disease process, systemic health status, and treatment history.

Active bleeding or fluid leak at the back of the eye (macula) warrants urgent treatment. Your ophthalmologist will perform appropriate scans — including OCT (Optical Coherence Tomography) to confirm, quantify, and monitor disease progression. The choice of agent is a clinical decision made by a trained and experienced retinal specialist, personalized to your individual needs.

Vision is measured at each visit and serves as a key yardstick for monitoring your response to treatment.

Administering Anti-VEGF Agents: Step-by-Step Guide

The anti-VEGF injection procedure is performed exclusively by a trained and qualified ophthalmologist in a sterile environment. Understanding how the anti-VEGF agent is injected into the eye can help reduce anxiety and help patients prepare better.

•   After clinical examination and relevant scans, a diagnosis is made and the doctor discusses available treatment options with the patient.
•   The anti-VEGF agent is administered into the eye using a fine needle under sterile conditions in an operating theatre.
•   The eye is numbed with a topical anaesthetic agent to ensure the procedure is painless.
•   The eye and surrounding structures are cleaned with an antiseptic solution.
•   A protective sheet called an eye drape is applied around the eye.
•   Eyelids are gently held open with a clip called an eyelid speculum.
•   The doctor injects the drug through the white part of the eye (sclera) using a fine needle.
•   After injection, a gentle massage is applied at the site of injection to normalize intraocular pressure.
•   The eye clip is removed, and antibiotic drops are instilled in the eye. Antibiotic drops are also prescribed for continued use post-procedure.

This step-by-step process is carried out only by a qualified retinal surgeon and typically takes less than 15 minutes from preparation to completion.

How is the anti-VEGF agent administered

• After clinical examination and relevant scans and making a diagnosis, the doctor will discuss the available options with the patient

• The anti-VEGF agent is administered into the eye by means of a fine needle under sterile conditions in an operation theater.

• The eyes are numbed with topical anaesthetic agent

• Cleaning of eyes and surrounding structures with an antiseptic solution is done

• Protective sheet called eye drape is applied around the eye

• Eyelids are opened with a clip called an eyelid speculum

• The doctor injects the drug through the white part of the eye through a fine needle

• After injection, gentle massage is done at the site of injection

• The eye clip is removed, and antibiotic drops are instilled in the eye

Antibiotic drops are prescribed for usage after injection in the eye.

Anti-VEGF Agents Available for Treatment

The following anti-VEGF agents are currently used in India for intravitreal injections. Their availability in India and intravitreal anti-VEGF injection price in India may vary depending on the clinical setting, hospital, and specific brand used.

• • Bevacizumab 

Bevacizumab is used off-label for intravitreal injections and remains among the most cost-effective options. While not FDA-approved for ocular use, extensive clinical data support its safety and efficacy. It is widely available across eye care centres in India and is often the most affordable option for patients requiring multiple injections.

• • Ranibizumab

Ranibizumab is FDA-approved and specifically engineered for intravitreal use. It is available under the brand name Accentrix/Lucentis in India. It is particularly preferred in cases requiring precision dosing and when systemic safety considerations are paramount.

• • Aflibercept

Aflibercept (Eylea) is FDA-approved and offers the advantage of extended dosing intervals (up to every 8–12 weeks after the loading phase), reducing the overall injection burden. It is available at major tertiary eye care centres in India.

• • Brolucizumab

Brolucizumab (Beovu) is the newest FDA-approved anti-VEGF agent and is increasingly being adopted at leading ophthalmology centres in India. It is particularly suited for patients with high fluid burden who benefit from extended treatment intervals.

Anti-VEGF injection therapy has fundamentally changed the way retinal diseases are managed. From wet AMD to diabetic macular edema and retinal vein occlusion, these agents offer the ability to preserve and even improve vision in conditions that were once considered untreatable. The choice of agent, dosing schedule, and monitoring plan should always be individualized guided by your retinal specialist based on your diagnosis, systemic health, and treatment response.

Early diagnosis and timely treatment are essential. If you are experiencing any visual disturbances, floaters, or a sudden drop in vision, consult an experienced ophthalmologist promptly.

Written by: Dr. Mohanraj – Consultant Ophthalmologist, Coimbatore