Why You Might Get an Eye Injection Before Vitrectomy Surgery for a Diabetic Tractional Retinal Detachment
The Shot Before Diabetic Retinal Detachment Surgery at a Glance
Most eye injections are quiet and dull. But a few signs mean you should call your retina team the same day, and not wait for your surgery date. The labels for these eye medicines say that shots into the eye have been linked to infection inside the eye and to retinal detachment. They tell you to seek immediate care from an eye doctor if the eye turns red, becomes sensitive to light, hurts, or your vision changes12
- Severe eye pain, or pain that gets worse after the first day
- A sudden drop in vision, or a new curtain or shadow across your sight
- A shower of new floaters, or new flashing lights
- A red eye with new light sensitivity
- Thick discharge, or a lid that swells shut
Now the calmer half. Serious infection inside the eye after a shot is rare. A large United States claims study counted it after 268 out of 481,572 Avastin injections3 Three hospitals in Korea counted about 3.64 cases in every 10,000 Avastin injections4 Caught early, it is far easier to treat. One phone call the same day is the whole job. If you cannot reach the office, go to an emergency room.
The shot is there to make your operation safer, not to replace it. The scar tissue tugging on your retina is fed by fragile new vessels that bleed as soon as a surgeon cuts and peels. A pre-surgery injection aims to shrink that abnormal blood supply first, so there is less bleeding during the operation5 In a Cochrane review of 28 trials covering 1,914 eyes, adding an anti-VEGF drug lowered accidental retinal tears during surgery, seen in about 12 of every 100 eyes with the drug against about 31 of every 100 without it6 Your retina is still detached afterwards. The vitrectomy is what puts it back.
If your surgery is booked a few days after the shot, that is on purpose. The drug quiets the blood vessels quickly, but the scar tissue left behind can tighten as it does. In one review, operating within 5 days of the bevacizumab injection was linked to less extensive scarring and fewer surgical complications, while operating more than 13 days afterwards was linked to a higher risk of a tractional retinal detachment starting or getting worse5 So if the surgery date slips, tell the office. The gap matters as much as the drug.
What a Diabetic Tractional Retinal Detachment Actually Is
It happens in slow steps over years. High blood sugar damages the tiny vessels feeding the retina, the light-sensing film at the back of your eye. The eye responds by growing new blood vessels that do not work well, and scars can form in the back of the eye. When those scars pull the retina away from the back of the eye, that is a tractional retinal detachment7 The new vessels and fibrous tissue sit where the jelly of the eye meets the retina, and can create the pulling forces that lift it5 Nothing here means you did something wrong. More than half of people with diabetes eventually develop some diabetic retinopathy7
Most retinal detachments start with a tear and arrive suddenly. Yours works differently. Often there is no hole at all: a sheet of scar tissue slowly tents the retina off the wall of the eye. That is why the vision change can be gradual, and why your surgeon may watch rather than rush. A tear can sometimes be sealed in the office, while traction has to be cut away from inside the eye.
Urgency here depends on one small patch of retina. The macula is the central part that gives you reading and face-recognition vision, and once traction reaches it the clock matters. A retina surgeon on an American Academy of Ophthalmology panel describes recommending surgery when the macula is already detached, and following a patient whose central vision is still attached with an Amsler grid so they can step in as the blind spot moves closer to the center8 If you have been offered a date, that judgment is already made. If you are watching and waiting instead, ask what change should make you call.
How the Injection Works and What the Surgery Does
Almost always it is an anti-VEGF drug, often the cheapest one. Anti-VEGF means a medicine that blocks a growth signal (clinical: vascular endothelial growth factor, the protein that tells new vessels to grow). Avastin, whose drug name is bevacizumab, is used most here. Avastin was developed as a cancer drug, and using it inside the eye for diabetic retinopathy is an off-label use that requires compounding pharmacies5 Off-label sounds alarming and mostly is not: it means the FDA has not reviewed this specific use, not that your surgeon is improvising. Eylea and Lucentis, the two versions made for the eye, are also used. Their labeled eye uses cover conditions such as diabetic retinopathy and diabetic macular edema2 Preparation for vitrectomy is not among them.
The drug starves the abnormal vessels rather than removing the scar. VEGF is the signal an oxygen-starved retina keeps sending, and it keeps leaky vessels alive inside the fibrous sheets on your retina. Block it for a few days and those vessels shrink, so the tissue your surgeon cuts bleeds much less. The American Academy of Ophthalmology's practice pattern states that anti-VEGF agents reduce the severity of diabetic retinopathy and effectively treat the proliferative stage9 What the drug cannot do is loosen scar tissue that has already formed.
This is the operation that reattaches your retina. Vitrectomy treats problems of the retina and vitreous, including diabetic retinopathy with bleeding or scar tissue, and can remove blood from inside the eye and scar tissue that is wrinkling or tearing the retina10 It is usually done at an outpatient surgery center under local or general anesthesia and takes one to several hours. The surgeon makes a small cut in the white of the eye, may use a laser, and may leave a gas bubble, or a silicone oil bubble removed at a second operation later11 Most people go home the same day.
The measured benefits are real, and mostly about bleeding and tearing. The Cochrane review found less bleeding into the eye in the first weeks after surgery with anti-VEGF, about 12 of every 100 eyes against about 31 of every 100, and less late bleeding, about 10 of every 100 against about 23 of every 1006 A review of 13 trials in 688 eyes reported shorter operating times, fewer accidental retinal breaks, less need for repeat surgery, and better long-term vision in the treated groups12 Vision at six months was somewhat better with anti-VEGF added, though the Cochrane authors graded that finding as low-certainty evidence6
Who Gets an Injection Before Surgery, and Who Does Not
The best candidate is an eye whose scar tissue is still full of live blood vessels. Your surgeon sees this at the slit lamp: fresh vessels that look red and full rather than white and empty, in a membrane likely to bleed when peeled. One retina surgeon on the Academy panel describes pretreating only when the membranes are very vascular, and then injecting just one or two days before the operation8 A surgery date you can keep matters too, because the benefit depends on the operation following closely.
Plenty of these operations are done without any injection, and that is legitimate. If the scar tissue has already gone white and bloodless, there is little abnormal vasculature left to shrink, so the drug has little to offer and the traction risk is not worth taking. Surgeons on the Academy panel describe rarely giving anti-VEGF before this surgery, and warn that a patient who has to be rescheduled may come back in a worse situation from a rebound effect8 If your surgeon is not injecting, ask why.
A few situations mean the shot should not be given that day. The labels for these eye medicines list an infection in or around the eye and a known allergy to the drug as reasons not to inject, and the aflibercept label adds active inflammation inside the eye12 Tell the office beforehand if you have a stye, a red or discharging eye, or a reaction to a previous injection. Say so too if you have had a recent stroke or heart attack, or if you are pregnant or might be. None of these is automatically a bar, but each changes the conversation.
Settling the Plan Before Your Surgery Date
Shorter and duller than almost everyone expects. Your doctor puts numbing medicine on the eye, cleans it to help prevent infection, and gives the medicine through a very small needle and syringe13 You stay awake, look in one direction, and a small clip stops you blinking on the needle. Most people describe pressure, not a sting. Injections do not change your vision straight away, and most people go back to normal activities right afterwards; irritation from the antiseptic and floating air bubbles that look like floaters are common13
The practical arrangements deserve an evening of planning. Ask what to do about your insulin or diabetes tablets on the morning of surgery, since you will likely be fasting. Ask whether to continue blood thinners; that is a decision for your surgical and medical teams together, never a rule to apply yourself. Arrange a driver, and if you can, someone to stay the first night. Managing your diabetes remains the best way to lower your risk from diabetic retinopathy, and controlling blood pressure and cholesterol helps too7
Recovering From the Injection and Then From the Surgery
Expect a gritty, bloodshot eye, and expect it to settle. The antiseptic is the usual reason it stings for a day, and a bright red patch on the white of the eye is a broken surface vessel, not a bleed inside. Floaters and small dark bubbles are common. What is not routine is pain that climbs after the first day, or vision that gets worse rather than better. Those are the same-day calls described at the top of this page.
This recovery is longer and more demanding than the injection. You may be given eye drops to use for up to 4 weeks and a patch for a few days, and you may be asked to hold your head in a particular position for a set period11 Positioning is what people underestimate: face-down for hours a day is genuinely hard, so borrow the right pillow or chair rest before surgery rather than after. Vision is usually blurry at first, because the bubble blurs everything above its edge.
One restriction is absolute, so put it in your calendar. You cannot fly in an airplane until the gas bubble is gone11 Altitude expands the bubble, and the pressure rise inside the eye can be dangerous. The same caution applies to mountain roads. If silicone oil was used instead, flying is not restricted the same way, but the oil usually needs a second, smaller operation later. Your surgeon will tell you which situation you are in.
Risks, Trade-Offs, and a Realistic Picture of Vision
It sounds paradoxical: the drug that calms the vessels can tighten the scar. As abnormal vessels shrink, the fibrous tissue around them can contract, and contracting tissue pulls harder on the retina. A multicenter study of 608 eyes given an anti-VEGF injection before vitrectomy found a tractional macular detachment in 61 of those 608 eyes, and the risk was lower when surgery was done within 6 days of the injection14 Reported rates of traction starting or worsening after the injection have ranged from about 1.5 to 18 of every 100 eyes in larger studies5 The practical protection is simple: keep the surgery date, and report a sudden vision change while you wait.
The injection carries the small risks of any needle entering the eye. Infection inside the eye is the serious one, and it is uncommon. Across 128,123 injections at three Korean hospitals, the overall rate of infection inside the eye was about 2.97 in every 10,000 injections4 A brief rise in eye pressure, a small surface bleed, and floaters are commoner and far milder. The aflibercept label also lists retinal detachment and raised pressure inside the eye among the risks, and tells patients to report suggestive symptoms without delay1 Rare and serious still earns a same-day phone call.
The larger risks belong to the operation, not the shot. The Academy lists infection, bleeding, a torn or detached retina, poor vision, and raised pressure inside the eye that can lead to glaucoma among the risks of vitrectomy10 Two more matter in diabetic eyes. Cataract, a clouding of the eye's own lens, often develops afterwards and is treated with routine cataract surgery. Bleeding can also recur, which is one of the problems the pre-surgery injection is meant to reduce.
The table sets the main hoped-for gains beside the main cost, using the figures cited above. These are group averages, not a forecast for your eye.
| What the injection changes | What the studies found |
|---|---|
| Bleeding into the eye soon after surgery | About 12 of every 100 eyes with the drug, about 31 of every 100 without |
| Accidental retinal tears during surgery | About 12 of every 100 eyes with the drug, about 31 of every 100 without |
| Operating time and repeat surgery | Both lower in the treated groups across 13 trials |
| Traction worsening before surgery | 61 of 608 eyes in one study; about 1.5 to 18 of every 100 across larger studies |
This is the honest part. Surgery for a diabetic tractional detachment is usually about holding on to the sight you still have, and it tends to go best before the macula has been detached for long. Retina surgeons on the Academy panel describe the outlook this way: despite the potential for successfully putting the retina back in place, the prognosis for visual rehabilitation (plain words: how much sight comes back) is guarded8 No one can tell you from a web page what your eye will do. Most people here are trading a slow loss for a chance at stability.
When to Call, and Who Should Be Managing This Eye
Between the injection and the operation, one change matters more than any other: a definite drop in your central vision, or a shadow spreading in from the side. That can mean the traction has progressed, and it can change how soon your surgeon operates. Phone the office the same day rather than waiting for the appointment. A checked eye that turns out stable costs you a phone call. An unchecked one that was not costs more.
Plenty of what alarms people is expected. After the injection, a red patch on the white of the eye and new floaters are usual. After vitrectomy, expect blurred vision, a mildly aching eye, a wobbling line across your sight from the bubble, and swollen lids. What separates normal from urgent is direction of travel: expected symptoms improve day by day, while pain that climbs and vision that keeps falling do not. Getting worse instead of better is the signal to call.
This belongs with a retina specialist, a vitreoretinal surgeon in particular. A tractional detachment from diabetes is one of the harder operations in eye surgery, and not something an optometrist or general ophthalmologist manages alone. Your optometrist still has a real role: monitoring the other eye and catching changes between visits. Your diabetes team matters as much as the eye team here.
Questions Patients Ask About the Injection Before Vitrectomy
No. The injection shrinks abnormal blood vessels, but it cannot release scar tissue that is already pulling your retina off the wall of the eye. That pulling is mechanical, and only surgery can cut it away. Some people hope a few shots will lift the retina back into place, and that is not how traction works. Think of the injection as preparation that makes the operation safer, the way a plumber shuts the water off first.
Before this surgery Avastin is the common choice, largely because it is inexpensive and acts quickly on abnormal vessels. Your friend may have been treated for a different problem, such as macular swelling, where the labeled eye drugs are standard. In the few days before surgery, surgeons generally treat the choice between them as a practical one.
Practice varies, and the published range is short. Some surgeons inject one or two days before, others up to five. What sources agree on is that a long gap is the problem: waiting well beyond a week raises the chance that scar tissue tightens before the operating room. Ask your surgeon for the interval planned in your case, and tell the office promptly if anything threatens to move your date.
Most people are surprised how little it hurts. The eye is numbed with drops or gel first, and the needle is very fine. What people report is a second or two of pressure, then a gritty feeling for a day, caused mainly by the antiseptic. If pain arrives later and grows rather than fading, that is different, and it needs a same-day call to your eye team.
Tell your surgeon's office as soon as you know. A delay is not automatically a disaster, but it is the specific thing that makes a pre-surgery injection riskier, because scar tissue can tighten after the drug takes effect. Your surgeon may bring the operation forward, find a cancellation slot, or arrange a repeat examination to check the traction.
Often yes, but this is a decision for your surgeon and the doctor who prescribed it, not one to make alone. One surgeon on the Academy panel reports rarely stopping blood thinners before this surgery8 The risk of stopping them can outweigh the extra bleeding risk in the eye. Bring an up-to-date list of every medicine and supplement to your pre-operative visit, and never stop a prescribed drug on your own.
More Questions About Surgery Day and What Comes After
Usually yes, in the sense that you are sedated rather than fully asleep. Many of these operations use local anesthesia, with an injection around the eye that numbs it and stops it moving, plus sedation to keep you comfortable. General anesthesia is used when the case is expected to be long or difficult, or when lying still would be hard.
Longer than most people expect, and the first weeks are not a fair test. If a gas bubble was used, vision stays poor until it shrinks and clears, which commonly takes several weeks. Swelling and a healing surface blur things further. Your surgeon will usually wait months before measuring your final vision. The endpoint depends on how much healthy retina you started with.
Many people do, for a different reason than before. After surgery, injections treat ongoing diabetic disease in the retina, such as swelling in the macula or new vessels that keep growing, rather than preparing for an operation. Some people also need laser treatment. Your retina specialist sets the schedule from what your scans show, and reviews it at each visit through the first year.
It can, and that is part of why follow-up is so close. Diabetic eyes can grow new scar tissue and new vessels after a vitrectomy, and a further operation is sometimes needed. Bleeding into the eye can also recur. Keeping your follow-up appointments is the practical protection, along with the blood sugar and blood pressure work.
Take this list to your pre-operative visit and write the answers down.
- Is the macula in my eye already detached, or is it still attached?
- Are you giving an injection before my surgery, and if not, why not?
- Exactly how many days will there be between the injection and the operation?
- Who do I call if my surgery date moves, or if my vision drops while I wait?
- Is the plan a gas bubble or silicone oil, and how long will positioning last?
- What is the realistic aim for this eye: keeping the vision I have, or regaining some?
- U.S. prescribing information for aflibercept (FDA label via DailyMed, U.S. National Library of Medicine) (2024). EYLEA (aflibercept) injection, for intravitreal use: full prescribing information.
- U.S. prescribing information for ranibizumab (FDA label via DailyMed, U.S. National Library of Medicine) (2024). LUCENTIS (ranibizumab injection) solution, for intravitreal injection: full prescribing information.
- Clinical Ophthalmology (Kiss S, Dugel PU, Khanani AM, Broder MS, Chang E, Sun GH, Turpcu A) (2018). Endophthalmitis rates among patients receiving intravitreal anti-VEGF injections: a USA claims analysis.
- Epidemiology and Health (Mun Y, You SC, Lee DY, Kim S, et al.) (2021). Real-world incidence of endophthalmitis after intravitreal anti-VEGF injections in Korea: findings from the Common Data Model in ophthalmology.
- International Journal of Retina and Vitreous (Arevalo JF, Beatson B) (2023). Pre-operative intravitreal bevacizumab for tractional retinal detachment secondary to proliferative diabetic retinopathy: the Alvaro Rodriguez lecture 2023.
- Cochrane Database of Systematic Reviews (Dervenis P, Dervenis N, Smith JM, Steel DHW) (2023). Anti-vascular endothelial growth factors in combination with vitrectomy for complications of proliferative diabetic retinopathy (Cochrane systematic review).
- National Eye Institute (NIH) (2025). Diabetic Retinopathy.
- EyeNet Magazine, American Academy of Ophthalmology (Schocket LS, Berrocal MH, Solomon SD, Thompson JT) (2024). Managing Severe Diabetic Retinopathy, Part 1: Tractional Retinal Detachment.
- American Academy of Ophthalmology (2024). Diabetic Retinopathy Preferred Practice Pattern (2024).
- American Academy of Ophthalmology, EyeSmart patient education (2026). What Is Vitrectomy?.
- American Academy of Ophthalmology, EyeSmart patient education (2020). What Happens During a Vitrectomy?.
- Therapeutic Advances in Ophthalmology (Dervenis P, Dervenis N, Steel D, Sandinha T, Tranos P, et al.) (2021). Intravitreal bevacizumab prior to vitrectomy for proliferative diabetic retinopathy: a systematic review.
- National Eye Institute (NIH) (2026). Injections to Treat Eye Conditions.
- Journal of Clinical Medicine (Russo A, Longo A, Avitabile T, Bonfiglio V, Fallico M, et al.) (2019). Incidence and Risk Factors for Tractional Macular Detachment after Anti-Vascular Endothelial Growth Factor Agent Pretreatment before Vitrectomy for Complicated Proliferative Diabetic Retinopathy.