Warning Signs After an Eye Injection: When to Call and When to Go to the ER
Warning Signs After an Eye Injection at a Glance
Most eyes feel fine after an injection. But a few signs mean you should act fast. Call your eye doctor the same day, or go to the ER, if you notice any of these:
- Severe eye pain that gets worse, not better, after the first day
- Sudden vision loss or fast-dropping vision in that eye
- A dark curtain or shadow moving across your sight
- A sudden shower of floaters or new flashing lights
- Growing redness with more light sensitivity or discharge
These are not the normal soreness of the first day. They can be the first sign of an eye infection, a pressure spike, or a torn retina. Getting seen right away gives your eye the best chance. If you cannot reach your retina specialist, go to the nearest emergency room.
An eye injection, usually an anti-VEGF shot for a retina condition, is one of the most common eye treatments, and serious problems are uncommon. A small red patch on the white of the eye, mild grittiness, and a few new floaters are common and harmless in the first day or two, and most of these minor effects settle on their own without treatment1. The skill is knowing which symptoms are the normal healing of a tiny needle stick and which ones are asking for a same-day call.
This page walks through both. It explains what is expected, what is a warning sign, how your retina specialist checks the eye, and exactly when a symptom means the office versus the emergency room.
Keep the phone number of your retina office where you can find it, and note any after-hours or on-call line. If a symptom on the list above appears, that number is your first call. For milder questions, the same office can tell you whether to come in or wait. When in doubt about a sudden change in vision or a painful eye, it is always reasonable to be checked rather than to wait and see.
What These Symptoms Mean After an Injection
An injection puts medicine into the jelly (clinical: vitreous) that fills the back of the eye through a very small opening. A red spot where the needle went in, called a subconjunctival hemorrhage, along with mild grittiness and a few floaters, is expected and usually clears within days1. The gritty feeling often comes from the cleaning solution used to keep the eye sterile, not from damage, and artificial tears usually ease it. Knowing this ahead of time keeps a normal red spot from becoming a scare.
None of these expected effects should be getting steadily worse after the first day. Normal soreness fades. A problem grows.
The clearest signal is the direction and timing of your symptoms. When a serious infection follows an injection, it usually appears within about 2 to 14 days as increasing pain, growing redness, and worsening vision rather than the mild soreness of the first day2. So the pattern to watch is not day-one discomfort but day-two-or-later worsening. Pain that deepens, redness that spreads, or vision that drops are the opposite of healing.
If your symptoms are fading each day, that is the reassuring pattern. If they are climbing, that is the pattern that earns a phone call.
Almost every serious after-injection warning sign points to one of three problems: an infection inside the eye, a sharp rise in eye pressure, or a tear or detachment of the retina. Each is uncommon, and each is treatable when caught early. The next section explains what each one is and the symptoms it tends to cause, so a warning sign leads you to the right kind of help rather than to guesswork.
What Causes Warning Signs After an Eye Injection
The most feared cause is an infection inside the eye, called endophthalmitis, when bacteria get into the eye through the injection site. Serious eye infection after an anti-VEGF injection is rare, occurring in about 35 of every 100,000 injections (roughly 1 in 3,000) in a pooled analysis of 276,774 injections3. It is rare, but it is the reason the warning-sign list exists, because prompt treatment protects sight. Its hallmark is worsening pain and vision a few days after the shot.
Adding fluid to a closed eye raises the pressure inside it for a short time. Eye pressure often rises briefly just after an injection and usually settles on its own, but a large spike can cause severe eye pain, a hard eye, blurred vision, and halos and needs prompt treatment4. Most pressure rises are small and pass within minutes to hours. A big spike is uncommon and tends to announce itself with real pain rather than mild soreness.
Rarely, the retina, the light-sensing layer at the back of the eye, can tear or begin to peel away. The National Eye Institute lists a sudden increase in floaters, flashes of light, and a dark curtain or shadow over the vision as warning signs that the retina may be detaching5. These symptoms can occur with or without a recent injection, and they carry the same meaning either way: get the retina examined without delay.
Normal After-Effects Versus Warning Signs
It helps to have a short list of what usually does not need a call. A red patch on the white of the eye, mild scratchiness, watering, and a small number of new floaters are the common, harmless effects of an injection and typically ease day by day1. A little tenderness around the eye and blurriness for a few hours from the cleaning drops or a gas bubble in the medicine are also expected. The theme is mild and improving.
If that describes your eye, artificial tears and time are usually all that is needed. Keep an eye on the trend rather than any single moment.
The same-day list is short and worth memorizing. Eye pain, decreased vision, increased floaters after the first day, or increased sensitivity to light after an injection are the symptoms that should prompt you to contact your retina specialist6. Add a spreading redness or any discharge to that list. You do not need to be certain what is wrong. Your job is to notice the change and make the call; sorting out the cause is the office's job.
The table below sums up the difference at a glance. Use it as a memory aid, not as a reason to delay a call when something feels wrong.
| Symptom | Usually normal | Warning sign |
|---|---|---|
| Redness | A single red patch that fades over days | Spreading redness that worsens after day one |
| Pain | Mild scratchiness or tenderness that eases | Severe or deepening pain |
| Vision | Brief blur that clears in hours | Vision that drops or keeps worsening |
| Floaters and flashes | A few small floaters that settle | A shower of floaters, flashes, or a shadow |
When a symptom sits in the right-hand column, treat it as a same-day call rather than something to sleep on.
How Your Retina Specialist Checks the Eye
When you call with a warning sign, the office will usually bring you in the same day. Tell them the date of your injection, which eye, and exactly how your symptoms have changed. That timeline matters, because a problem starting on day three points in a different direction from soreness on the evening of the shot. If the office is closed and your vision is dropping or your eye is very painful, the emergency room is the right place to go.
The exam is quick and painless. Your doctor checks your vision, measures the eye pressure, and looks inside the eye with a bright microscope. Because a serious infection typically shows increasing pain, redness, and worsening vision in the days after an injection, the exam focuses on signs of inflammation inside the eye and on the clarity of the eye's fluid2. If the retina cannot be seen clearly, an ultrasound scan of the back of the eye may be used to check for infection or a detachment.
Treatment depends on the cause and starts fast when needed. An infection is usually treated with antibiotic medicine placed directly into the eye, sometimes with a small sample taken first to find the exact germ. A dangerous pressure spike can be lowered with drops or by releasing a tiny amount of fluid. A retinal tear is often sealed with laser or freezing treatment, and a detachment is repaired with surgery. The common thread is that early care makes each of these more manageable.
How Often Serious Problems Happen and the Outlook
It is worth keeping the numbers in view, because fear grows in the dark. In a pooled analysis of 276,774 injections, serious eye infection occurred in about 35 of every 100,000 injections, roughly 1 in 3,0003. That means the overwhelming majority of injections cause nothing worse than a red spot and a day of mild soreness. The warning-sign list is a seatbelt, not a forecast; you wear it because the rare event is serious, not because it is likely.
For the rare serious problem, speed is the single biggest thing you control. Among people who suddenly notice new floaters or flashing lights, about 14 of every 100 (roughly 1 in 7) are found to have a retinal tear on examination, which is why these symptoms are checked quickly7. A tear caught early can often be sealed in the office before it becomes a detachment. An infection treated on the day it declares itself has a better chance than one that waits a weekend. Fast action does not guarantee a perfect result, but it consistently improves the odds.
For most people, the honest outlook is reassuring. The expected after-effects clear within days, and the injection does its job of protecting the retina. Even when a serious problem does appear, catching it early gives many people a good chance of keeping useful vision. The realistic message is not that nothing can go wrong, but that problems are uncommon and that you have real power to change the outcome by acting on a warning sign.
When to Call Versus When to Go to the ER
Your retina office is the right first call for most warning signs during working hours. Eye pain, decreased vision, more floaters after the first day, or increased light sensitivity after an injection are the symptoms that should prompt a same-day call to your retina specialist6. They know your eye and your history and can usually see you quickly. Bring the date of your injection and a clear description of how things have changed.
Some situations should not wait for a callback. Go to the emergency room if you have sudden severe vision loss, a very painful eye that will not settle, a dark curtain or shadow spreading across your sight, or these symptoms after office hours when you cannot reach your retina team. The emergency room can start care and reach an eye specialist. It is always reasonable to be checked for a sudden change in vision rather than to wait until morning.
Not everything is urgent, and it helps to know what can wait. A single red spot that is fading, mild scratchiness, a few floaters that are settling, or questions about your next appointment can all wait for regular office hours. So can general questions about your medicine or your schedule. If a symptom is mild and improving each day, a routine call is fine. If it is severe or getting worse, move it up to the same-day or emergency list.
Common Questions About Warning Signs After an Eye Injection
Yes, a red spot is one of the most common and harmless after-effects. A small pool of blood on the white of the eye, called a subconjunctival hemorrhage, happens when a tiny surface vessel is nicked, and it usually clears within a week or two without treatment. What is not normal is redness that spreads and worsens after the first day, especially with pain or dropping vision. A single fading red patch can wait; a spreading, worsening red eye deserves a same-day call.
Watch the direction and the timing. Normal soreness is mild and fades a little each day, and it usually comes from the cleaning drops rather than the injection itself. A serious problem tends to start on day two or later and to worsen, bringing deepening pain, spreading redness, or vision that drops. If your symptoms are easing, that is reassuring. If they are climbing, call your retina specialist the same day rather than waiting to see what happens.
Most serious infections show up within about two to fourteen days of the injection, not on the first evening. They usually announce themselves with increasing pain, growing redness, and worsening vision, which is different from the mild soreness right after the shot. Because the window stretches to about two weeks, it is worth staying alert to worsening symptoms for that whole period and calling promptly if pain or vision changes for the worse.
Usually not, if it clears within hours. Some blur is expected from the cleaning drops, from a gas bubble in the medicine, or from the eye simply being disturbed. This kind of blur tends to lift the same day. What is concerning is vision that drops and stays down, or that keeps getting worse over the following days. Short-lived blur on the day of the injection is common; persistent or worsening vision loss is a same-day warning sign.
It is a rare risk, and the warning signs are the same as a detachment from any cause. Watch for a sudden increase in floaters, new flashes of light, or a dark curtain or shadow crossing your vision. These symptoms mean the retina needs to be examined without delay, whether or not you recently had an injection. A detachment caught early can often be repaired with a good chance of protecting vision, so do not wait on these particular symptoms.
Use the severity to decide. If you have sudden severe vision loss, a very painful eye, or a spreading curtain or shadow, go to the emergency room rather than waiting for morning. If the symptom is mild and stable, such as a little scratchiness or a fading red spot, it is reasonable to call your retina office when it opens. Many retina practices also have an after-hours line, so keep that number handy for exactly this situation.
More Questions Patients Ask About After-Injection Symptoms
Not usually, and routine antibiotic drops are no longer standard after these injections. Research has not shown that they lower the already-low risk of infection, and some studies suggest they do not help. Your retina specialist cleans the eye with an antiseptic before the injection, which is the step that matters most for preventing infection. If your doctor does not send you home with antibiotic drops, that reflects current evidence, not a gap in your care.
Most retina offices will bring you in the same day for a true warning sign, because timing affects the outcome for infection, pressure spikes, and retinal problems. When you call, say the date of your injection, which eye is affected, and how your symptoms have changed since the shot. That information helps the team gauge urgency. If they cannot see you quickly and your vision is dropping or your eye is very painful, the emergency room is the right backup.
Most pressure rises after an injection are small and pass on their own within minutes to hours. A large spike is uncommon and usually causes real symptoms, such as severe eye pain, a hard-feeling eye, blurring, and halos around lights. Those symptoms deserve a same-day call or a trip to the emergency room, where the pressure can be lowered quickly. Brief, mild discomfort that settles is expected; severe pain with halos is not.
It depends entirely on the cause, which is exactly why guessing is risky. Some problems, like a serious infection or a spreading detachment, can worsen over hours, so a lost day can matter. Others are minor and would be fine. Because you cannot tell from the outside which one you have, the safe habit is to treat a true warning sign as same-day, not next-week. Being checked and reassured costs little; waiting on a serious problem can cost vision.
Bringing a few focused questions to your injection visit helps you feel prepared. Consider asking:
- Which specific symptoms after this injection should make me call you the same day?
- What is your after-hours or on-call number if a problem starts at night or on a weekend?
- How long after the injection should I stay alert for signs of infection?
- Is any redness, soreness, or floating spot expected in my case, and for how long?
- Should I use artificial tears or avoid anything in the first day or two?
- If I cannot reach your office, at what point should I go straight to the emergency room?
- Retinal Physician (clinical review) (2022). Complications of Intravitreal Injections.
- Journal of Ophthalmology (case series, PMC10643029) (2023). Postintravitreal Injection Endophthalmitis: Incidence, Characteristics, Management, and Outcome.
- Scientific Reports (peer-reviewed meta-analysis, PMC5741717) (2018). Intravitreal injections of anti-VEGF agents and antibiotic prophylaxis for endophthalmitis: a systematic review and meta-analysis.
- Retinal Physician (clinical review) (2022). Complications of Intravitreal Injections (intraocular pressure).
- National Eye Institute (NEI, NIH) (2024). Retinal Detachment.
- American Society of Retina Specialists (ASRS) (2024). Intravitreal Injections (patient information).
- JAMA, Rational Clinical Examination systematic review (Hollands et al.) (2009). Acute-Onset Floaters and Flashes: Is This Patient at Risk for Retinal Detachment?.