An intravitreal injection is an eye procedure in which medicine is injected into the vitreous cavity, the gel-filled space behind the lens and in front of the retina. It is used to deliver a high concentration of medicine to the back of the eye while limiting exposure elsewhere in the body.
Intravitreal injections are common in modern ophthalmology, especially for retinal disease. They are usually performed as outpatient procedures under local anaesthetic drops.
Uses
Intravitreal injection is used for conditions affecting the retina, macula, or vitreous. Common uses include:
- Wet age-related macular degeneration.
- Diabetic macular oedema.
- Retinal vein occlusion.
- Some cases of diabetic retinopathy.
- Eye infection or inflammation, where antibiotics, antivirals, antifungals, or steroid medicines may be needed inside the eye.
The Royal College of Ophthalmologists identifies neovascular age-related macular degeneration, diabetic macular oedema, and retinal vein occlusion as common UK indications for intravitreal therapy.
Medicines
The best-known group of intravitreal medicines is anti-VEGF treatment. VEGF stands for vascular endothelial growth factor, a signal involved in abnormal blood-vessel growth and leakage. Blocking VEGF can reduce leakage and swelling in several retinal conditions.
Medicines used by intravitreal injection may include anti-VEGF drugs, corticosteroid implants or injections, antibiotics, antivirals, antifungals, and other specialist medicines. The exact medicine depends on the diagnosis, eye findings, licensing, local policy, and the patient's previous response to treatment.
Procedure
The procedure varies by clinic, but usually follows a standard pattern:
- The patient's identity, eye, medicine, and consent are checked.
- Anaesthetic drops are used to numb the eye.
- The eye and surrounding area are cleaned with antiseptic.
- A sterile field is prepared.
- The eyelids are held open.
- A very small needle is passed through the white of the eye into the vitreous cavity.
- The medicine is injected and the needle is removed.
- Vision, comfort, and aftercare instructions are checked before discharge.
The injection itself is brief. Patients may feel pressure, watering, grittiness, or mild irritation afterwards. Some people see transient floaters or bubbles after the injection.
Safety and Infection Control
Intravitreal injection involves entering the eye, so sterile technique is central. Royal College of Ophthalmologists guidance stresses that anything injected into the eye must remain sterile, the setting and equipment must be suitable, and staff must be trained to manage complications.
Endophthalmitis, a serious infection inside the eye, is rare but potentially sight-threatening. Antiseptic preparation, careful checking, and clear aftercare instructions are therefore important parts of the procedure.
Follow-Up
Follow-up depends on the condition and medicine. Anti-VEGF treatment often requires repeated injections over months or years, with monitoring by visual acuity testing, optical coherence tomography scans, and clinical examination.
For chronic retinal disease, missed appointments can affect outcome. Many services use planned recall systems so patients receive treatment and review at the intended interval.
Risks
Possible risks include:
- Eye pain, redness, watering, or surface irritation.
- Temporary rise in eye pressure.
- Floaters or transient blurred vision.
- Bleeding on the surface of the eye.
- Inflammation inside the eye.
- Infection inside the eye.
- Retinal tear or retinal detachment.
- Cataract or lens injury, which is uncommon.
Patients are usually told to seek urgent advice if pain, redness, worsening vision, increasing light sensitivity, or discharge develops after an injection.
Role in Retinal Care
Intravitreal injection changed the treatment of several retinal diseases. Conditions that previously led to progressive central vision loss, particularly wet age-related macular degeneration, can often be stabilised or improved with timely treatment.
The burden of treatment can be high because some conditions need repeated visits. This has made clinic capacity, consent, safe delegation, follow-up systems, and patient information important parts of retinal service planning.
References
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