Your Complete Guide to Anti-VEGF Injection Treatment at Precision Retina Care
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Version: 1.0 | Created: July 2026 | Last Reviewed: July 2026 | Next Review Date: July 2027
What is Retinal Vein Occlusion?
Understanding RVO
The retina is the light-sensitive layer at the back of your eye that captures images and sends them to your brain so you can see.
Retinal vein occlusion (RVO) occurs when a vein in the retina becomes blocked. This blockage prevents blood from flowing out of the eye normally. When blood backs up behind the blockage, it leaks into the retina and macula, the central part of the retina responsible for sharp vision.
Why does this happen? The exact cause is not always clear, but RVO typically occurs when a blood clot forms in a retinal vein or when the vein is compressed. Risk factors include high blood pressure, glaucoma, and blood-clotting disorders.
The impact
- Sudden blurred or cloudy vision in one eye
- Floaters, which are small spots or lines floating in your vision
- Dark or missing areas in your vision
- Vision loss that develops suddenly or over several days
- Difficulty reading or recognizing faces
Two Types of RVO
Branch Retinal Vein Occlusion (BRVO)
- A smaller vein is blocked
- Affects part of the retina
- Vision loss is usually localized to one area
- Generally has a better visual prognosis
Central Retinal Vein Occlusion (CRVO)
- The main vein is blocked
- Affects the entire retina
- Vision loss can be more significant
- Requires close monitoring and treatment
Key Point About RVO
RVO is a serious eye condition that requires prompt evaluation and treatment. However, modern anti-VEGF treatment is effective at preserving and sometimes improving vision when started early.
Am I at Risk for RVO?
Risk Factors
Your risk for RVO increases if you have:
- High blood pressure or hypertension: The most common risk factor
- Glaucoma: Increased eye pressure
- Diabetes: Damages blood vessels
- High cholesterol: Affects blood-vessel health
- Blood-clotting disorders: Increase clot risk
- Age: RVO is more common as you get older
- Smoking: Damages blood vessels
- Obesity: Associated with hypertension and diabetes
- Atherosclerosis: Hardening of the arteries
- Recent eye surgery or trauma
Reducing Your Risk
Although some risk factors cannot be changed, you can take steps to reduce your overall risk:
- Control your blood pressure: This is the most important factor. Work with your doctor to maintain healthy levels.
- Manage other health conditions: Keep diabetes, high cholesterol, and glaucoma well controlled.
- Take medications as prescribed: Do not skip doses of blood-pressure or other medications.
- Maintain a healthy lifestyle: Exercise regularly, eat a heart-healthy diet, and maintain a healthy weight.
- Stop smoking: If applicable, quitting is one of the best things you can do.
- Have regular eye exams: Early detection of eye problems is important.
- Manage stress: Chronic stress can affect blood pressure.
Why Early Detection Matters
Many people do not realize they have RVO until significant vision loss has occurred. Regular eye exams are essential because:
- RVO can develop suddenly with minimal warning
- Early detection allows for prompt treatment
- Prompt treatment helps preserve vision
- Delayed treatment may result in permanent vision loss
Recognizing the Symptoms
Warning Signs You Should Know
Contact your eye doctor immediately if you notice:
- Sudden vision loss or blurring in one eye
- Sudden onset of floaters or dark spots
- Blurry or distorted vision that develops suddenly
- Dark or blank areas in your visual field
- Flashing lights in your vision
- Sudden difficulty seeing to the side, or peripheral vision loss
- Hazy or cloudy vision in one eye
- Sudden difficulty reading or seeing fine details
- Pain in or around the eye, which may indicate another condition
When to Seek Urgent Care
Seek emergency evaluation immediately if you experience:
- Sudden complete vision loss in one eye
- Sudden vision loss with eye pain
- Any sudden, significant change in vision
Do not wait for a routine appointment. Call your eye doctor the same day or go to an emergency room. Rapid evaluation of RVO is critical because prompt treatment helps preserve vision.
How is RVO Diagnosed?
Comprehensive Eye Examination
Your ophthalmologist will perform several tests to diagnose RVO and determine the extent of the condition.
Visual Acuity Test
Your doctor will check how clearly you can see with an eye chart.
Dilated Eye Examination
Your pupils will be dilated or widened using special drops. This allows your doctor to examine the entire retina and identify the blocked vein and any associated swelling.
Diagnostic Testing
Diagnostic testing is individualized and may include:
- Optical coherence tomography (OCT): Creates detailed cross-section images of the retina to measure fluid and swelling
- Retinal photography: Detailed photos of the retina showing the blocked vein and blood-vessel changes
- OCT angiography: Shows blood-vessel circulation patterns and identifies the blockage location
- Fluorescein angiography: Uses dye injected into your arm to highlight the blockage and areas of leakage
- Other imaging when clinically indicated
Additional Tests
Your doctor may also check:
- Your blood pressure
- Blood tests if a blood-clotting disorder is suspected
- Intraocular pressure for glaucoma screening
Treatment Options for RVO
Anti-VEGF Injections
VEGF stands for “vascular endothelial growth factor”—a protein that tells the body to grow new blood vessels.
The problem: In RVO, the blocked vein causes blood and fluid to back up in the retina. The retinal tissue responds by producing VEGF, which causes additional abnormal vessel growth and increased leakage. This leads to macular edema, or swelling, and vision loss.
The solution: Anti-VEGF medications are injected directly into the eye. They block this protein, preventing abnormal vessel growth and stopping fluid leakage.
The result
- Fluid gradually decreases in the retina and macula
- Swelling decreases
- Vision stabilizes
- In many patients, vision improves significantly
- The progression of vision loss is halted
Your ophthalmologist will recommend a medication that is appropriate for your condition. Your doctor will discuss the evidence, benefits, risks, and approval status of the recommended medication.
Treatment recommendations are based on your ophthalmologist’s clinical assessment, current evidence, and your individual circumstances.
Timeline: What to Expect
Phase 1: Initial Evaluation Before Treatment Starts
Precision Retina Care provides specialized assessment and treatment clinics for patients with wet age-related macular degeneration, diabetic macular edema, and retinal vein occlusion. Our structured approach includes comprehensive assessment with diagnostic testing to confirm the diagnosis and develop a personalized treatment plan tailored to your specific condition.
First appointment
- Comprehensive eye examination
- Individualized diagnostic testing that may include OCT, retinal photography, OCT angiography, fluorescein angiography, and other imaging when clinically indicated
- Review of your medical history, including blood pressure and cardiovascular health
- Discussion of treatment options
- Answers to your questions and concerns
What we are determining
- Is it definitely RVO?
- Is it BRVO or CRVO?
- Which vein is blocked?
- What is the extent of the blockage and damage?
- Is there macular edema or swelling?
- Is an anti-VEGF injection the right treatment for you?
- Which treatment option is most appropriate for your condition?
- Are there any contraindications?
- How well is your blood pressure currently controlled?
What you should do
- Write down your questions beforehand
- Bring a list of all current medications, especially blood-pressure medications
- Bring recent blood-pressure readings if you monitor at home
- Ask about costs and insurance coverage
- Discuss any concerns about the procedure
- Arrange transportation if you will need it
Phase 2: Intensive Treatment During Months 1–3
Initial Schedule: Monthly Injections
Most patients receive injections in Month 1, Month 2, and Month 3.
What Happens at Each Injection Appointment
Duration: Up to one hour in total, including preparation and monitoring.
- Registration and paperwork: five to 10 minutes
- Arrive 10–15 minutes early
- Check in and confirm your information
- Pre-injection testing: approximately 20 minutes
- Visual-acuity check to measure how clearly you see
- Intraocular-pressure measurement
- OCT imaging to assess fluid levels
- These tests are painless and quick
- Dilating the eyes for a complete examination: approximately 30 minutes
- Dilating drops are placed in your eyes
- The drops allow a complete examination of the retina
- Your doctor performs a thorough evaluation of the back of the eye
- The blocked vein and any swelling are carefully assessed
- Numbing and preparation: approximately five minutes
- Anaesthetic eye drops are placed in the eye
- Your eye will feel numb and tingly
- The injection area is prepared using sterile techniques
- A protective drape is placed
- The injection: less than 30 seconds
- You will see a bright light from the speculum holding your eye open
- You may feel pressure, but the eye is numb
- The actual injection is very brief
- Some patients report seeing a flash or feeling slight pressure
- Post-injection care: approximately five minutes
- Your ophthalmologist will provide appropriate post-procedure medications or instructions
- Your eye may feel slightly scratchy, which is normal
- You will rest briefly
- You will receive instructions for home care
- Discharge: approximately five minutes
- You will be cleared to go home
- Most patients can resume their usual activities shortly after the procedure
- Your ophthalmologist may recommend temporary restrictions based on your circumstances
- Mild grittiness in the eye is normal for a few hours
After Your Injection
Important: Everyone experiences the injection process differently. If you experience anything unexpected after your injection, contact your doctor’s office. Precision Retina Care provides written instructions and emergency contact information so you know how to reach the team if you have concerns.
Possible sensations after the injection
- Some grittiness or mild discomfort in the eye
- Floaters or small shadows, which should be reported if they persist or worsen
- Slight redness that may last for hours or days
- Mild sensitivity to light
If you experience anything that concerns you
- Contact your doctor’s office
- Do not wait to see whether symptoms resolve on their own
- The care team is available to help and answer your questions
- Use the emergency contact information provided in your written instructions
Physical Sensations During the Injection
Everyone experiences the injection differently. Although your eye is numbed with anaesthetic drops, you may feel some discomfort during the procedure. Most patients tolerate the injection well.
What you might feel
- Pressure in the eye
- Awareness of the syringe approaching because you will see the light
- Brief discomfort or mild, tolerable pain as the medication enters
- Brief dimming of vision
- Sensitivity to the speculum holding your eye open
What to know
- Numbing drops are used to minimize discomfort
- The procedure is very brief
- Any discomfort is temporary
- Patients generally tolerate the procedure well
Phase 3: Maintenance and Monitoring During Month 4 and Beyond
After the first three injections, your treatment plan will be adjusted based on your response.
Common Maintenance Schedules
Every four weeks
- Used if the eye continues to have fluid
Every six weeks
- Some eyes respond well with less frequent injections
Every eight weeks
- Some medications can be extended to this interval if vision is stable
Every 12 weeks
- Some patients with well-controlled RVO may achieve this interval
Individualized approach
- Your schedule is based on your specific response
- Your doctor closely monitors your progress
- Your schedule may change as your condition evolves
- Controlling your blood pressure helps optimize your response to treatment
The Importance of Managing Your Overall Health
Why Blood Pressure Matters
Managing your blood pressure during RVO treatment is critical because:
- RVO is often caused or worsened by high blood pressure
- Better blood-pressure control improves the response to treatment
- Uncontrolled hypertension increases the risk of RVO developing in the other eye
- Good control protects your retinal health
Before Each Appointment
Bring:
- Your blood-pressure readings if you monitor at home
- A list of your current blood-pressure and other medications
- Any questions about your health management
- Recent blood-pressure records
Discussing Your Overall Health With the Team
Tell your ophthalmologist if:
- Your blood pressure has been difficult to control
- You have changed your blood-pressure medications
- You have other cardiovascular conditions
- You are experiencing medication side effects
- You are having difficulty taking your medication as prescribed
Your eye-care team and primary-care doctor work together to help manage both your overall health and your eye condition.
What to Bring to Appointments
Every visit
- OHIP card
- Photo ID
- List of current medications, including blood-pressure medications
- Blood-pressure readings if you monitor at home
- Written questions or concerns
- Amsler-grid results if you are self-monitoring
- Notepad to record instructions
- Consider arranging transportation, particularly for your first treatment
First visit
- Medical history, especially cardiovascular conditions and blood-pressure control
- List of all current medications and supplements
- Information about any previous eye surgery or injury
- Family history of eye disease and blood-clotting disorders
- Recent blood-pressure readings if available
Key Questions to Ask Your Doctor
Before starting treatment
- Why is this medication recommended for me?
- What are the side effects?
- How will we know whether treatment is working?
- What is the expected injection schedule?
- What happens if I need to skip an injection?
- Are there activities I should avoid?
- How does my blood-pressure control affect treatment?
- Will my other eye develop RVO?
During treatment
- How am I responding to the medication?
- Do we need to adjust the schedule?
- What should I monitor between visits?
- When can I expect to see improvement?
- What are realistic goals for my vision?
- Are other treatments available?
Long term
- How long will I need injections?
- Can I ever stop treatment?
- What happens if I stop receiving injections?
- What is the prognosis for my vision?
- What can I do to prevent RVO in my other eye?
- How does managing my health affect treatment?
Tips for a Smooth Treatment Experience
Before Each Appointment
- Arrange transportation: Consider arranging transportation, particularly for your first treatment or if your pupils will be dilated.
- Eat a light breakfast or lunch.
- Take your regular medications as scheduled, including blood-pressure medications.
- Wear comfortable clothing.
- Remove jewellery or accessories that might get in the way.
- Remove your contact lens from the eye being treated, if applicable.
- Check your blood pressure before coming if you monitor at home.
At the Office
- Arrive 10–15 minutes early.
- Take deep breaths to remain relaxed.
- Ask questions about the procedure.
- Tell the staff if you are anxious.
- Follow all instructions carefully.
- Ask for clarification if you do not understand something.
Managing Anxiety
Many patients are anxious before their first injection. This is completely normal.
Things that help
- Understanding what to expect
- Having someone with you for support, particularly if transportation is needed
- Deep-breathing exercises
- Asking staff questions before the procedure
- Remembering that numbing drops are used
- Focusing on the goal of preserving your vision
Talk to your doctor if
- Your anxiety is overwhelming
- You need additional time or support
- You want to discuss options that may make the procedure easier
Potential Side Effects and What to Watch For
Although mild scratchiness and discomfort for a few hours after an injection can be normal, contact your doctor immediately if you notice any of the following.
Rare but Serious: Call Immediately
- Severe eye pain
- Significant decrease in vision
- Persistent floaters that worsen
- Signs of infection, including increasing redness, pus, or warmth
- Bleeding or new spots in your vision that do not improve
- A sudden appearance of numerous new floaters
Serious Complications: Very Rare
Serious complications from anti-VEGF injections are extremely rare. When they occur, they may include:
- Retinal detachment
- Endophthalmitis, or an eye infection
- Cataract progression
Important: Your doctor will review the warning signs with you and provide written instructions explaining how to contact the office or seek urgent help. Keep this information accessible and do not hesitate to reach out with concerns.
Realistic Expectations
What Anti-VEGF Can Do
- Stop vision loss in most patients
- Reduce macular swelling or edema
- Stabilize vision so that it does not worsen
- Significantly improve vision in many patients with RVO
- Slow disease progression
- Reduce the risk of permanent vision loss
What Anti-VEGF Cannot Do
- Remove the blood clot; the blockage may remain
- Restore vision that was already lost before treatment began
- Cure RVO, which is a chronic condition requiring ongoing management
- Work immediately; improvement takes weeks to months
- Prevent RVO in the other eye, although monitoring helps detect problems early
Timeline for Results
- After the first injection: You may see minimal change.
- After the second injection: Some improvement in swelling may be visible.
- After the third injection: The maximum effect is usually seen.
- Ongoing: Stability is maintained with continued treatment.
Some patients respond faster and others more slowly. The response is individual and depends on factors such as blood-pressure control and the severity of the RVO.
Managing Treatment Long Term
Staying Committed to Treatment
Once anti-VEGF treatment begins, staying consistent is crucial because:
- Disease progression can resume quickly if treatment stops
- Fluid can return within days or weeks
- Vision loss from missed appointments may be permanent
- Regular monitoring helps optimize treatment
Managing Your Overall Health During Treatment
Your overall health affects your treatment outcome:
- Work closely with your primary-care doctor
- Control your blood pressure effectively
- Take blood-pressure medication exactly as prescribed
- Monitor your blood pressure regularly
- Avoid smoking and excess sodium
- Maintain a healthy diet and weight
- Exercise as tolerated
Making Treatment Work With Your Schedule
If appointments are difficult
- Talk to your doctor about your challenges
- Ask about early-morning or late-afternoon appointments
- Ask whether another staff member can help address barriers
- Ask about transportation resources
If you are struggling financially
- Financial-assistance programs may be available for eligible patients, depending on the medication prescribed
- Discuss cost concerns with your doctor
- Ask about available options
- Patient advocates may be able to help
If you are struggling emotionally
- It is normal to feel anxious about vision loss and retinal disease
- Ask about support groups or counselling
- Talk to your doctor about your concerns
- Connect with other people living with RVO
When to Adjust or Change Treatment
Your doctor may recommend treatment changes if:
- You are not responding well: The eye continues to have fluid despite treatment
- You experience side effects: Significant adverse effects develop
- A different medication is needed: Another anti-VEGF medication may work better
- The interval can be adjusted: The eye is responding and injections can be spaced farther apart
- The dosage should be adjusted: A different dose may be more suitable
- Blood-pressure problems interfere with treatment: Uncontrolled hypertension may limit treatment success
Never stop or change treatment on your own. Always discuss changes with your doctor.
Clinical Trials at Precision Retina Care
Precision Retina Care is involved in a number of clinical trials in AMD, diabetic macular edema, and retinal vein occlusion.
If you are eligible for a study
- You will be informed about potential research studies and opportunities
- Study information will be discussed with you
- You can ask questions about participation
- Participation is offered only when appropriate and after a separate informed-consent discussion
Important
- Participation in research is completely voluntary and independent of clinical care
- Choosing not to participate will not affect your treatment or care at Precision Retina Care
- Your clinical care remains the primary focus
Frequently Asked Questions
About the Injection
Does it hurt?
Everyone experiences the injection differently. The eye is numbed with drops, but you may feel some discomfort during the procedure. Most patients tolerate the injection well, and any discomfort is brief.
Can I see the needle going in?
You will see a bright light and be aware of the syringe approaching, but the procedure is very quick.
Is there any bleeding?
Occasionally, minor bleeding develops under the conjunctiva, the clear membrane covering the white of the eye. This is harmless and resolves on its own.
About the Process
How long does the whole appointment take?
The appointment usually takes up to one hour, including check-in, testing, the injection, and monitoring.
Can someone come with me?
Yes. Having someone with you can provide support, particularly for your first appointment. This is especially recommended if your pupils will be dilated or you would prefer to have someone present.
Do I need to take time off work?
Most people do not. The procedure is quick, and you can usually resume normal activities immediately.
Can I drive home after the injection?
Your ability to drive depends on whether your pupils were dilated and your individual circumstances. Discuss this with your ophthalmologist before your appointment. If your pupils are dilated, your vision may be temporarily affected and you should consider arranging transportation.
About Results
When will I see improvement?
This varies. Some patients see improvement within weeks, whereas others require several months. Stabilization of vision and reduction in swelling are common outcomes.
What if I do not see improvement?
Talk to your doctor. Your medication, dosage, or treatment frequency may be adjusted. Sometimes a different anti-VEGF medication works better. Blood-pressure control also affects your response.
How long will I need treatment?
RVO is a chronic condition. Most patients need ongoing treatment for months or years, although the frequency may decrease as the condition stabilizes.
Can my blood pressure affect treatment?
Yes, significantly. Uncontrolled blood pressure can limit the effectiveness of treatment and increase the risk of vision problems. Good blood-pressure control is essential for the best outcomes.
About Safety
Is the medication safe?
Your ophthalmologist will recommend a medication appropriate for your condition and discuss its evidence, benefits, risks, and approval status.
What about my other eye?
Both eyes should be monitored regularly. If you have had RVO in one eye, the other eye has a higher risk. Regular check-ups can identify problems early. Tell your doctor immediately if you notice changes in your other eye.
Can I have an allergic reaction to the medication?
True allergies are very rare. Report unusual symptoms to your doctor.
Will treatment prevent RVO in my other eye?
Treatment in one eye does not prevent RVO in the other. However, good blood-pressure control and regular eye exams help identify problems early.
Your Role in Success
Successful treatment depends on a partnership between you and your medical team.
What your doctor does
- Carefully monitors your response
- Adjusts treatment as needed
- Provides skilled injections
- Communicates with your referring doctor and primary-care team
What you do
- Keep all appointments
- Self-monitor using the Amsler grid
- Report vision changes promptly
- Take medications as prescribed
- Maintain good overall health and blood-pressure control
- Ask questions and communicate concerns
- Stay engaged in your care
- Work with your primary-care doctor
Living Well With RVO and Treatment
Daily Life
- Continue regular activities as tolerated
- Exercise and stay active to support blood pressure and eye health
- Maintain a healthy diet low in sodium
- Wear UV-protective sunglasses
- Monitor your blood pressure as directed
- Do not smoke
- Monitor your vision daily using the Amsler grid
Maintaining Independence
Many people maintain their independence and quality of life while receiving anti-VEGF treatment for RVO, including:
- Driving when appropriate
- Reading and participating in hobbies, with adaptations as needed
- Working and socializing
- Travelling
- Staying engaged in life
Emotional Support
It is normal to have mixed feelings about an RVO diagnosis and treatment, including:
- Fear about vision loss and blindness
- Frustration with managing a chronic retinal condition
- Worry about treatment effectiveness
- Concern about cardiovascular health
These feelings are valid. Consider:
- Connecting with other people who have RVO
- Talking to a counsellor or therapist
- Joining a retinal-disease support group
- Discussing concerns with your healthcare team
When to Reach Out to Your Doctor
Contact your doctor before your next scheduled appointment if:
- Your vision changes significantly
- You develop new symptoms
- You notice new floaters or shadows
- You have concerns about treatment
- You are struggling with the appointment schedule
- You have questions about your condition
- You want to discuss alternative treatments
- Your blood pressure has been difficult to control
- You have changed your blood-pressure medication
Resources
At Precision Retina Care
- Your care team is available to support you
- Ask for educational materials
- Request referrals to support services
- Discuss concerns openly
Eye-Health Resources
- American Academy of Ophthalmology
- National Eye Institute
- Patient support organizations for retinal disease
- Low-vision rehabilitation services
Cardiovascular-Health Resources
- Your primary-care doctor
- Cardiologist, if applicable
- Blood-pressure management programs
- Heart-disease support organizations
Summary: Your Treatment Journey
- Evaluation: Comprehensive assessment and treatment planning
- Initial phase: Three monthly injections during Months 1–3
- Monitoring: Regular visits to assess your response
- Maintenance: Ongoing injections on an individualized schedule
- Long term: Continued treatment to preserve vision and manage cardiovascular health
The goal is to preserve your vision and maintain your quality of life through consistent, evidence-based treatment combined with good overall health management.
Final Thoughts
Retinal vein occlusion is a serious eye condition, but modern treatment works. Combined with good overall health management, regular injections and monitoring can help many patients:
- Stop their vision loss
- Reduce retinal swelling
- Stabilize or improve their vision
- Maintain independence and quality of life
You are not alone in this journey. Your eye-care team, primary-care doctor, family, friends, and other people living with RVO are here to support you.
Addendum
Clinical Care Provider
Clinical care is provided by Dr. Varun Chaudhary and the Precision Retina Care team at the Hamilton Regional Eye Institute.
Medical Review and Approval
This patient-education guide has been reviewed and approved by Dr. Varun Chaudhary, MD, FRCSC, an ophthalmology specialist with expertise in retinal disease.
Accessibility
This guide is available in large print, audio format, and alternative formats upon request. Please call the office to request an alternative format.
Educational Use
This guide is intended for patient education and does not replace individualized medical advice from your ophthalmologist. Always follow the recommendations provided by your treating eye specialist.
Precision Retina Care | Retina Consultants of Hamilton