Eye injections have become a routine and generally safe procedure for managing several serious eye diseases. This treatment involves delivering medication directly into the vitreous cavity, the gel-filled space at the back of the eye, to target the retina. Conditions such as wet age-related macular degeneration (AMD), diabetic macular edema, and retinal vein occlusion are commonly treated with this method to preserve vision. While the procedure is quick and the overall risk profile is low, patients can expect a range of side effects, most of which are minor and temporary. Understanding the difference between expected reactions and signs of a rare, serious complication is important for proper post-procedure care.
Temporary and Expected Reactions
The most common symptoms following an injection are generally mild and are a direct result of the procedure itself, typically resolving within 24 to 48 hours. Many patients notice a red spot on the white of the eye, which occurs when the needle punctures a tiny blood vessel on the surface. This spot is harmless, analogous to a small bruise, and will naturally fade over one to two weeks.
A feeling of mild irritation, often described as having grit or a foreign body in the eye, is also very common immediately after the injection. This sensation is frequently caused by the antiseptic solution used to sterilize the eye surface before the procedure. Accompanying this may be excessive tearing or a mild burning sensation, which can be managed with artificial tears.
Vision may be temporarily blurred or hazy immediately following the procedure, sometimes accompanied by increased sensitivity to light. This visual change is often due to the residual anesthetic drops, the antiseptic wash, and the injected medication settling in the eye. The blurring typically improves over the first day, and wearing sunglasses can help manage light sensitivity. Many people also report seeing small specks or bubbles immediately after treatment. These specks are harmless air bubbles introduced during the injection and usually dissipate from the line of vision within a few days.
Less Common Ocular Changes
Beyond the immediate irritation, other internal changes may occur that are less frequent but still require monitoring. A temporary increase in intraocular pressure (IOP) is an expected event that occurs within minutes of the injection due to the added volume of fluid. The eye’s natural drainage system usually compensates quickly, bringing the pressure back to baseline.
In some instances, a sustained elevation of IOP can occur, particularly in patients who receive steroid-based injections or have pre-existing conditions like glaucoma. This sustained pressure needs monitoring, as repeated, unmanaged spikes can potentially damage the optic nerve over time.
The appearance of new or increased floaters may be a sign of a more internal change, distinct from the temporary air bubbles. While floaters can be caused by the medication or a change in the vitreous gel, a sudden shower of new floaters, especially if accompanied by flashes of light, warrants immediate attention. Another less common occurrence is a small vitreous hemorrhage, which is bleeding into the center of the eye. This may cause a temporary shadow in the vision that absorbs on its own.
Serious Risks Requiring Immediate Attention
Certain risks pose a threat to vision and demand immediate medical intervention. The most severe risk is endophthalmitis, a serious internal eye infection that occurs in a very small fraction of injections (typically 0.01% to 0.3%). The infection usually develops within the first few days after the procedure and can rapidly lead to permanent vision loss if not treated promptly.
The warning signs of endophthalmitis include severe and worsening eye pain, a significant and sudden decrease in vision, and the presence of pus or discharge from the eye. Increasing redness that is not limited to the initial injection site is also a concerning symptom. Any patient experiencing worsening pain and reduced vision should contact their eye specialist immediately.
Another rare but serious complication is retinal detachment, where the light-sensitive tissue at the back of the eye pulls away from its underlying support layers. This can occur directly from the injection procedure itself, with reported rates generally below 0.7%. Symptoms often involve a sudden increase in floaters, flashes of light, or the appearance of a shadow or curtain moving across the field of vision.
Post-Injection Care and Monitoring
Proper care following the injection is important for minimizing the risk of infection and supporting the healing process. Patients are advised to avoid rubbing or pressing on the treated eye for at least the first few days to prevent irritation. The ophthalmologist may prescribe antibiotic and anti-inflammatory eye drops, which must be used exactly as directed to prevent infection and control inflammation.
Restrictions on water exposure are necessary because tap water and certain sources can harbor bacteria, increasing the risk of infection. Patients are instructed to avoid swimming, hot tubs, and saunas for up to one week following the injection. While showering is usually permissible, avoid direct water contact with the treated eye for the first 24 to 48 hours.
Attending all scheduled follow-up appointments is necessary to allow the doctor to monitor the eye’s internal pressure and check for complications. Patients should be vigilant in monitoring their symptoms at home, especially in the first few days. If pain or vision is worsening instead of improving, the patient must contact the treating ophthalmologist right away for an urgent assessment.