Endophthalmitis: Protecting Your Vision From Eye Infection
Understanding Endophthalmitis
Endophthalmitis is a severe infection that develops inside the eye. It affects the vitreous (the clear gel that fills the eye) and the aqueous humor (the fluid in the front of the eye). Infectious organisms such as bacteria or fungi enter the eye and trigger an intense inflammatory response. This inflammation can damage the retina and other delicate structures.
The infection causes white blood cells to accumulate inside the eye. This buildup can create a visible white or yellow layer in the front of the eye called a hypopyon. The vitreous gel becomes cloudy as the infection spreads. This blocks light from reaching the retina and causes rapid vision loss.
There are two main categories based on how the infection enters the eye. Exogenous endophthalmitis occurs when organisms enter from the outside. This can happen during surgery, after an injury, or following an injection into the eye. This is the most common type.
Endogenous endophthalmitis occurs when organisms spread to the eye through the bloodstream from an infection elsewhere in the body. This type is less common but can be more difficult to diagnose. There may not be a recent eye procedure or injury to raise suspicion.
Acute endophthalmitis develops rapidly, usually within two to seven days after surgery, trauma, or an injection. Symptoms are sudden and severe, including intense pain and rapid vision loss. This form demands immediate emergency treatment.
Chronic endophthalmitis develops slowly over weeks or even months. Symptoms may be mild at first and gradually worsen. Certain organisms, such as Propionibacterium acnes, tend to cause this slower form. Although less dramatic in its onset, chronic endophthalmitis still requires prompt treatment to protect vision.
Who Is Affected and Risk Factors
The most common cause of endophthalmitis is eye surgery, particularly cataract surgery. Recent Medicare data show that post-cataract surgery rates decreased from 1.53 per 1,000 surgeries in 2012 to 1.11 per 1,000 surgeries in 2019 (AAO, 2023). While this decline is encouraging, endophthalmitis remains one of the most feared complications of cataract surgery.
Other surgical procedures carry risk as well. Corneal transplantation and secondary intraocular lens placement have been associated with higher infection rates. Complicated surgeries where the posterior lens capsule is disrupted also increase risk.
Intravitreal injections (injections of medication directly into the eye) are among the most frequently performed eye procedures. These injections treat conditions such as wet age-related macular degeneration and diabetic macular edema. The risk of endophthalmitis after an intravitreal injection is approximately 0.035% per injection, or about 1 in 2,857 injections (AAO Journal, 2024). Although this rate is very low, patients who receive many injections over time have cumulative exposure to this risk.
Penetrating injuries to the eye carry a significant risk of endophthalmitis. The infection rate following penetrating ocular trauma ranges from 4% to 13% and may reach up to 30% after injuries in rural settings (ASRS). Rural injuries pose a greater danger because soil and organic materials can introduce aggressive organisms. Injuries that leave a foreign body inside the eye are especially high risk.
Endogenous endophthalmitis is linked to conditions that weaken the immune system or allow infections to enter the bloodstream. Key risk factors include:
- Diabetes
- HIV or AIDS
- Active chemotherapy or immunosuppressive therapy
- Systemic infections or septicemia (blood infection)
- Intravenous drug use
- Indwelling catheters or other long-term medical devices
Research shows that certain demographic factors increase the likelihood of developing endophthalmitis. Adults over age 75 face higher risk, as do males. Patients with high comorbidity scores, meaning they have multiple coexisting health conditions, are also more vulnerable. These factors may relate to slower wound healing and a less robust immune response.
Signs and Symptoms
Endophthalmitis is a medical emergency. Any of the following symptoms, especially within days of eye surgery, an injection, or an eye injury, require immediate evaluation. See a retina specialist or go to the emergency room immediately:
- Severe eye pain that worsens rapidly
- Sudden and significant vision loss
- Increasing redness of the eye
- White or yellow discharge from the eye
- A visible white or yellow layer in the front of the eye
- New floaters or shadows in your vision
- Significant sensitivity to light
Acute bacterial endophthalmitis typically appears within two to seven days after a procedure or injury. In some cases, symptoms can develop as early as 24 hours after surgery. The speed of progression depends on the type of organism. More aggressive bacteria, such as Streptococcus species, cause faster and more severe symptoms.
Chronic endophthalmitis may not produce noticeable symptoms for weeks or months. Patients may notice gradually worsening vision, mild discomfort, or persistent redness. Because symptoms develop slowly, chronic cases can be mistaken for other inflammatory conditions.
Patients with acute endophthalmitis often describe intense, deep eye pain not relieved by over-the-counter pain medication. Vision may drop from normal to very poor within hours. The eye typically appears very red, and the eyelids may swell. Some patients notice a visible cloudy or white area in the pupil. Any combination of pain, redness, and vision loss following an eye procedure should be treated as a potential emergency.
Diagnosis and Testing
A retina specialist will perform a thorough examination using a slit lamp (a special microscope for examining the eye). The specialist looks for signs of inflammation, including cells floating in the front chamber. A hypopyon (white blood cell accumulation at the bottom of the front chamber) and cloudiness of the vitreous gel are key findings. The degree of vitreous haze helps gauge infection severity.
To identify the specific organism causing the infection, the retina specialist may collect fluid samples from inside the eye. A vitreous tap involves removing a small amount of vitreous gel with a needle. An aqueous tap collects fluid from the front chamber. These samples are sent to a laboratory for culture and sensitivity testing. The results help determine which antibiotics will be most effective.
B-scan ultrasonography is often used when the vitreous is too cloudy for the specialist to see the retina. The ultrasound can reveal the extent of vitreous inflammation, detect retinal detachment, and identify foreign bodies inside the eye. For suspected endogenous endophthalmitis, blood cultures and systemic workup may be performed to find the original source of infection.
Treatment Options
The cornerstone of endophthalmitis treatment is the injection of antibiotics directly into the vitreous cavity. This delivers a high concentration of medication right where the infection is occurring. The standard combination includes vancomycin for gram-positive bacteria (such as Staphylococcus and Streptococcus) and ceftazidime for gram-negative bacteria. Some centers also use intravitreal moxifloxacin for broader antibacterial activity.
These injections are performed as an emergency procedure, often within hours of diagnosis. Treatment should not be delayed while waiting for culture results. Time is critical in preserving vision.
Vitrectomy (a surgery to remove the vitreous gel from inside the eye) may be recommended in more severe cases. The landmark Endophthalmitis Vitrectomy Study found that patients who could only see light perception or worse benefited from immediate vitrectomy combined with intravitreal antibiotics. Patients with better vision at diagnosis may be treated with antibiotics alone initially. Vitrectomy is reserved if the infection does not improve.
During vitrectomy, the retina specialist removes the infected vitreous gel. This reduces the bacterial load and the concentration of inflammatory toxins inside the eye. The specialist can also collect a larger vitreous sample for analysis and ensure medication reaches all areas of the eye.
Fungal endophthalmitis requires different medications than bacterial cases. Intravitreal antifungal drugs such as amphotericin B or voriconazole are used. Unlike bacterial cases, fungal endophthalmitis typically also requires systemic (oral or intravenous) antifungal therapy. Fungal infections tend to progress more slowly but can be more difficult to eradicate. Longer treatment courses are often necessary.
For exogenous endophthalmitis (caused by surgery or injury), the role of systemic antibiotics is debated among specialists. They are not routinely prescribed for all cases. However, systemic antibiotics are essential for endogenous endophthalmitis because the infection originates from elsewhere in the body. Treating the primary source of infection is critical.
Supportive measures may include topical antibiotic eye drops and corticosteroid eye drops to control inflammation (used carefully under close supervision). Pain management is also part of the care plan. The retina specialist will monitor the eye closely with frequent follow-up visits in the days and weeks following treatment.
What to Expect
When endophthalmitis is suspected, treatment begins immediately. The retina specialist will numb the eye with local anesthesia before collecting fluid samples and injecting antibiotics. If vitrectomy is needed, it may be performed in an operating room under local or general anesthesia. The entire process from diagnosis to initial treatment typically happens within hours.
Patients can expect discomfort during and after the procedure. The eye will likely be red, swollen, and sore for several days. Pain medication may be prescribed. Follow-up visits are usually scheduled within one to two days to assess the response to treatment.
Recovery from endophthalmitis varies widely depending on the severity of infection, the organism involved, and how quickly treatment began. Some patients recover meaningful vision, while others experience lasting vision loss despite aggressive treatment. Infections caused by less aggressive organisms, such as coagulase-negative Staphylococci, tend to have better outcomes. More virulent bacteria like Streptococcus or Bacillus species are associated with worse results.
Full recovery can take weeks to months. The retina specialist will monitor the eye throughout this period. Complications such as retinal detachment, elevated eye pressure, or recurrence of infection may develop. Additional treatments or surgeries may be needed in some cases.
Even with prompt treatment, endophthalmitis can lead to serious complications. These may include:
- Lasting vision loss ranging from mild to severe
- Retinal detachment
- Phthisis bulbi (shrinkage of the eye)
- Chronic inflammation
- Need for additional surgeries
The best way to reduce the risk of complications is to seek treatment as early as possible. Every hour matters when it comes to treating this infection.
When to See a Retina Specialist
See a retina specialist or go to the emergency room immediately if you experience any combination of severe eye pain, rapid vision loss, or increasing eye redness. This is especially critical within the first week after eye surgery, an intravitreal injection, or an eye injury. Do not wait to see if symptoms improve on their own. Endophthalmitis is a time-sensitive emergency where delays in treatment can result in severe or total vision loss.
Contact a retina specialist if you notice gradually worsening vision, mild but persistent eye discomfort, or ongoing redness weeks or months after an eye procedure. These could be signs of chronic endophthalmitis or another inflammatory condition. Any unexplained change in vision after an eye procedure deserves professional attention.
Questions and Answers
While endophthalmitis cannot be prevented with certainty, several measures significantly reduce risk. Surgeons follow strict sterile techniques during eye procedures. The use of antiseptic solutions such as povidone-iodine before surgery and injections has been shown to lower infection rates. Intracameral antibiotics during cataract surgery have also shown promise. Patients can help by following all pre-procedure and post-procedure instructions carefully and avoiding touching or rubbing their eyes during healing.
Endophthalmitis after intravitreal injections is rare, occurring at a rate of approximately 0.035% per injection, or about 1 in 2,857 injections (AAO Journal, 2024). Retina specialists take multiple precautions to minimize this risk, including antiseptic preparation of the eye surface and wearing sterile gloves. Patients who receive regular injections should remain aware of the warning signs so they can seek care immediately if needed.
Visual outcomes depend on several factors, including the type of organism, the severity of infection at diagnosis, and how quickly treatment begins. Infections caused by less aggressive bacteria such as coagulase-negative Staphylococci generally have better results. More aggressive organisms like Streptococcus or Bacillus species are associated with worse outcomes. Early diagnosis and rapid treatment offer the best chance of preserving vision.
No. Endophthalmitis is an infection inside the eye, which makes it far more serious than common external eye infections like conjunctivitis (pink eye) or a stye. External infections affect the surface of the eye or the eyelids and are usually treated with topical drops or ointments. Endophthalmitis affects the internal structures of the eye, including the vitreous and the retina. It requires emergency intervention with injections into the eye or surgery. The two conditions should not be confused, as endophthalmitis can lead to severe or total vision loss without proper treatment.
Endophthalmitis after cataract surgery is uncommon, occurring in approximately 1 in 1,000 cases based on recent data (AAO, 2023). Modern surgical techniques and infection prevention protocols have helped lower this rate over time. While it is natural to have concerns, the overall risk is low. The most important step you can take is to follow all pre-surgery and post-surgery instructions. Learn the warning signs so you can seek immediate care if anything seems wrong during recovery.