Endophthalmitis

What is endophthalmitis?

The inside of the eye is normally sterile. Endophthalmitis happens when bacteria or, less often, fungi get into the vitreous (the clear gel that fills the back of the eye) and the aqueous fluid in the front chamber. The immune response floods the eye with white blood cells, which can settle as a visible pale layer at the bottom of the iris called a hypopyon. The toxins and inflammation can quickly damage the retina.

If the infection spreads beyond the eye wall into the orbit, it is called panophthalmitis, which is even more serious.

Types and causes

After surgery (post-operative)

This is the most common form. After cataract surgery it occurs in roughly 1 in 1,000 to 1 in 2,000 operations. Most cases appear within 1 to 2 weeks, typically on days 3 to 7. Bacteria from the patient's own eyelids and skin, such as coagulase-negative staphylococci, are the usual cause. A slower, low-grade form caused by less aggressive bacteria can appear weeks to months later.

After eye injections

Injections for macular degeneration and diabetic eye disease carry a small risk, roughly 1 in several thousand injections. Mouth bacteria such as streptococci are more common here, which is why staff and patients avoid talking during the injection.

After an eye injury (post-traumatic)

Penetrating injuries cause up to about 1 in 10 cases of open-globe injury, especially when a foreign body remains in the eye or the wound is contaminated with soil. Bacillus species can destroy the eye within a day.

From the bloodstream (endogenous)

Bacteria or fungi travel to the eye from elsewhere. Risk factors include diabetes, IV drug use, long-term IV lines, endocarditis, liver abscess (particularly Klebsiella), recent surgery and a weak immune system. Candida (yeast) is a common fungal cause. Both eyes can be affected.

Symptoms

• Eye pain that gets worse rather than better after surgery
• Blurred, dim or rapidly worsening vision
• Red eye and swollen eyelids
• Light sensitivity
• A white or yellow layer in the front of the eye (hypopyon)
• Discharge and lid swelling in some cases
• In fungal or endogenous cases, floaters and slowly worsening blur over days to weeks, sometimes with fever

Some people, especially after an injection, have little pain, so blurred vision alone after a procedure needs checking.

How it is diagnosed

An ophthalmologist examines the eye with a slit lamp and checks pressure and vision. If the view of the retina is blocked, an ultrasound scan of the eye shows debris in the vitreous. A small sample of fluid from the front chamber and the vitreous is taken with a fine needle for culture and PCR testing to identify the organism.

In endogenous cases, blood cultures, heart ultrasound and scans look for the source of infection. Endophthalmitis needs to be distinguished from uveitis and from toxic anterior segment syndrome, a non-infectious inflammation that appears within 12 to 48 hours of cataract surgery.

Treatment

Treatment starts the same day:

• Intravitreal antibiotics: after taking samples, the doctor injects antibiotics (usually vancomycin plus ceftazidime) directly into the vitreous. This "tap and inject" is the cornerstone of treatment. Drops and tablets alone cannot reach high enough levels inside the eye.
• Vitrectomy: surgery to remove the infected gel. The Endophthalmitis Vitrectomy Study found it particularly helpful after cataract surgery when vision had fallen to light perception only. It is used more widely today, and routinely for trauma-related cases.
• Antifungal treatment: injections into the eye plus oral or IV antifungals for fungal infections.
• Systemic antibiotics: essential in endogenous cases to treat the source infection.
• Steroid and dilating drops: to calm inflammation and ease pain once infection is being treated.

Outlook

Results depend on the organism and the speed of treatment. Many people with infections from skin staphylococci recover useful vision. Infections with streptococci, Bacillus or gram-negative bacteria have a worse outlook, and some eyes lose all sight or need removal. Complications include retinal detachment, glaucoma and shrinkage of the eye.

Prevention

Surgeons use povidone-iodine antiseptic on the eye surface before every procedure, and many give antibiotic into the eye at the end of cataract surgery. After surgery, use your drops exactly as prescribed, avoid rubbing the eye, keep tap water and makeup away for the advised period, and report any worsening pain or vision immediately.

Frequently asked questions

What are the first signs of endophthalmitis after cataract surgery?

Pain that increases instead of easing, vision that gets worse after initially improving, and redness that deepens are the key early signs. They usually appear between days 2 and 7. Contact your eye surgeon or eye emergency service the same day.

How quickly does endophthalmitis cause vision loss?

Aggressive bacteria can cause severe damage within 24 hours, which is why treatment is given the same day as diagnosis. Fungal and low-grade bacterial infections progress more slowly, over days to weeks.

Is endophthalmitis contagious?

No. It is an infection inside one person's eye and does not spread to other people. Endogenous endophthalmitis can affect both eyes because it spreads through the bloodstream.

Can you recover from endophthalmitis?

Many people do regain useful vision, especially when the infection is caused by less aggressive bacteria and treatment starts early. Outcomes are poorer with virulent organisms or delayed treatment, and some people are left with permanent vision loss.