Intravitreal Injection: How It Works, Results and What to Expect

An intravitreal injection is a common outpatient eye procedure that places medicine into the vitreous, the gel-like substance inside the eye. It is used to treat several retinal conditions and can help preserve vision, reduce retinal swelling, or control abnormal blood vessel growth.

Overview: how an intravitreal injection works

An intravitreal injection is a procedure in which an ophthalmologist injects medication into the vitreous, the clear gel that fills most of the eye. Delivering medicine in this way allows it to reach the retina and macula at a therapeutic level. The retina is the light-sensitive tissue at the back of the eye, while the macula is the central area responsible for detailed, straight-ahead vision.

These injections are most often used to reduce leakage and swelling in the retina or to slow the growth of abnormal, fragile blood vessels. Many medicines used are anti-VEGF drugs, which block vascular endothelial growth factor (VEGF), a signal that can promote abnormal vessel growth and leakage. Other injected medicines, including corticosteroids, may be appropriate in selected situations.

The procedure is usually performed in an outpatient eye clinic under local anaesthetic drops. It does not involve an incision or general anaesthesia, and patients generally return home the same day. The treatment plan is individual: some people need an initial series of injections, while others receive treatment at longer intervals based on examination findings and retinal imaging.

Who may benefit from retinal injections

An intravitreal injection may be recommended for conditions that affect the retina or macula. Common reasons include wet age-related macular degeneration, diabetic macular oedema, diabetic retinopathy, retinal vein occlusion, and some inflammatory eye diseases. In these conditions, fluid, bleeding, inflammation, or abnormal blood vessels can interfere with retinal function and threaten vision.

Suitability depends on the diagnosis, the location and severity of retinal changes, previous treatments, general health, and the patient’s visual needs. An ophthalmologist evaluates the eye with a dilated examination and commonly uses optical coherence tomography (OCT), a non-invasive scan that shows fluid and retinal layers in fine detail.

Injections may not restore vision that has already been permanently lost from scarring or advanced retinal damage. However, timely treatment may prevent further deterioration and, in many people, improve vision affected by active swelling or leakage. The goal should be discussed clearly before treatment, including how progress will be measured over time.

• Wet age-related macular degeneration
• Diabetic macular oedema and proliferative diabetic retinopathy
• Macular oedema after retinal vein occlusion
• Selected cases of uveitis or other retinal inflammation
• Some eye infections, when specialist-directed injection treatment is needed

What happens during the procedure

Before the injection, the eye team confirms the treatment eye and medication. The eye is cleaned with an antiseptic solution to reduce infection risk. Anaesthetic drops, gel, or a small local anaesthetic injection are used so that the procedure should not be painful, although brief pressure or a momentary sensation may still be noticed.

The eyelids are kept open with a small device or gentle support. The ophthalmologist injects the medication through the white part of the eye, called the sclera, at a carefully selected location away from the central cornea and retina. The injection itself usually takes seconds. The team may check vision, eye pressure, or the eye’s appearance afterward, depending on the clinical situation.

Most appointments are longer than the injection because they may include visual acuity testing, pupil dilation, OCT imaging, and discussion of the treatment plan. It is sensible to arrange transport home when dilation has been used, as driving may be difficult until vision clears. Patients should tell the clinician about eye pain, infection symptoms, recent eye surgery, medication allergies, and blood-thinning medicines, but should not stop prescribed medicines without medical advice.

Recovery timeline after an intravitreal injection

Recovery is usually quick. Mild scratchiness, tearing, redness at the injection site, and sensitivity to light can occur on the day of treatment and commonly settle within 24 to 48 hours. A small red patch on the white of the eye is often caused by a minor surface blood vessel bleed; it can look noticeable but usually resolves gradually over days to a couple of weeks.

Blurred vision may occur for several hours, particularly after pupil dilation. Some people notice small bubbles, dots, or moving shadows immediately after the injection. These are often related to the medication or tiny air bubbles and tend to fade within a day or two. The eye care team may provide lubricating drops or specific instructions if discomfort occurs.

Visual improvement from the medicine is not always immediate. In some cases, OCT scans show reduced fluid before the person notices a meaningful change in sight. Follow-up timing varies by condition and medicine, but regular monitoring is important because retinal activity can return without obvious symptoms. Keeping scheduled appointments helps the ophthalmologist adjust treatment safely.

Benefits, risks and realistic results

The main benefit of an intravitreal injection is targeted treatment of retinal disease. Anti-VEGF therapy can reduce fluid in the macula and control abnormal blood vessels, while steroid treatment can reduce inflammation and swelling in appropriate cases. For many retinal disorders, injections have changed the outlook from progressive vision loss to stabilisation or improvement for a substantial number of patients.

Results are variable rather than guaranteed. They depend on the cause of retinal damage, how early treatment begins, the degree of swelling or scarring, the response to medication, and whether treatment visits can be maintained. The treating ophthalmologist will review vision testing and retinal imaging to explain whether the eye is responding and whether the interval between injections can change.

Serious complications are uncommon but require prompt attention. These can include infection inside the eye (endophthalmitis), retinal tear or detachment, significant bleeding, raised eye pressure, cataract progression with some steroid treatments, or inflammation. The clinic should provide clear instructions about symptoms that require urgent review.

Patients seeking coordinated retinal assessment and treatment may discuss their options with ophthalmology specialists at Acibadem International, where JCI-accredited hospitals support international patients with multidisciplinary care.

What not to do after an intravitreal injection

For the rest of the day, patients should avoid rubbing or pressing on the treated eye. Hands should be washed before using any eye drops, and only drops recommended by the eye specialist should be used. Temporary blurring can make driving, operating machinery, or reading fine print unsafe until sight has cleared.

Many clinics advise avoiding swimming pools, hot tubs, and getting potentially contaminated water directly into the eye for a short period, often around 24 to 48 hours. Contact lens use should follow the ophthalmologist’s individual instructions. Normal gentle activities are usually possible, but people should ask their eye team about strenuous exercise or heavy lifting if they have additional eye conditions or have recently had surgery.

It is important not to miss follow-up visits simply because the eye feels better. Retinal fluid or abnormal blood vessels can recur before symptoms are noticed. Patients should also avoid self-treating significant pain or worsening visual symptoms with leftover eye drops; they should contact an eye professional instead.

When to seek medical care

Mild irritation, temporary blurred vision, and a small area of redness can be expected after an injection. However, severe or increasing eye pain, worsening redness, marked sensitivity to light, pus-like discharge, a substantial or persistent drop in vision, or increasing floaters should be assessed urgently. These symptoms can occasionally indicate infection, inflammation, pressure changes, or another complication that needs timely care.

Emergency assessment is also needed for flashes of light, a sudden shower of floaters, or a dark curtain or shadow across the vision, as these may be warning symptoms of a retinal tear or detachment. Patients should use the urgent contact route provided by their injection clinic, or seek emergency eye care if they cannot reach the clinic promptly.

Even without urgent symptoms, patients should contact their ophthalmologist if discomfort is not improving after a couple of days, if they are unsure about their drops or activity restrictions, or if an appointment needs to be rescheduled. Ongoing care is a key part of protecting retinal health.

Frequently asked questions

How long does it take to recover from an intravitreal injection?

Most people recover from the immediate effects within one to two days. Mild grittiness, tearing, light sensitivity, and a red patch on the white of the eye can occur, while blurred vision from dilation may last several hours. The recovery of vision from the retinal condition itself may take days to weeks and depends on the reason for treatment.

What is the success rate of intravitreal injections?

There is no single success rate because intravitreal injections treat different diseases and use different medicines. In many people, treatment stabilises vision or improves retinal swelling, especially when started before extensive permanent damage occurs. The ophthalmologist assesses response through vision tests and retinal scans over repeated visits.

What not to do after an intravitreal injection?

Patients should avoid rubbing or pressing on the eye and should not drive until vision is clear. They should follow their clinic’s advice about swimming, hot tubs, contact lenses, eye drops, and strenuous activities. Severe pain, worsening redness, or a significant change in vision should not be ignored.

How long does the retina take to kick in after an injection?

The retina does not “kick in” in the same way as a muscle; the injected medicine begins acting on retinal leakage, abnormal blood vessels, or inflammation after it is delivered. Some people notice improvement within days, while others need several weeks or repeated injections before changes are apparent. OCT scans may show improvement before vision noticeably changes.

Does an intravitreal injection hurt?

The eye is numbed before the injection, so most people feel pressure, a brief pinch, or little sensation rather than significant pain. Mild scratchiness afterward is common and usually short-lived. Severe or worsening pain is not expected and needs urgent advice from the eye clinic.

How often are intravitreal injections needed?

Frequency depends on the retinal condition, the medicine used, and how the eye responds. Some treatment plans begin with injections every few weeks, then extend the interval if retinal scans remain stable. Others use treatment only when monitoring shows recurrent fluid or disease activity.

References

• American Academy of Ophthalmology
• National Eye Institute
• Royal College of Ophthalmologists
• National Health Service

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.