The Endophthalmitis Vitrectomy Study (EVS) is the randomized trial that defined the initial treatment of acute endophthalmitis after cataract surgery.
Its main message is that vision at presentation decides the procedure: a tap and injection for patients who can also see hand motions.
An immediate vitrectomy for those with light perception only (see acute postoperative endophthalmitis).
Design of the Endophthalmitis Vitrectomy Study
The study enrolled 420 patients with clinical endophthalmitis within six weeks of cataract surgery or secondary lens implantation. Their vision ranged from hand motions to light perception (see the references).
Patients were randomized in a two-by-two design.
- Immediate pars plana vitrectomy or a vitreous tap and biopsy
- Intravenous amikacin and ceftazidime or no intravenous antibiotics
All patients received intravitreal vancomycin and amikacin, and subconjunctival antibiotics and steroids.
Endophthalmitis Vitrectomy Study: Results for Vitrectomy
In eyes with hand motion or better vision, vitrectomy gave no advantage over a tap (see the references).
In eyes with light perception vision, immediate vitrectomy tripled the chance of a final acuity of 20/40 or better, 33 percent against 11 percent. It also halved the rate of severe loss.
Fundus Explorer Pro
Photograph the retinal findings described here with the phone already in your pocket — 22 D optics and built-in illumination in one handheld unit.
From Choroida — the team behind this siteEndophthalmitis Vitrectomy Study: Intravenous Antibiotics
Intravenous antibiotics gave no benefit in visual outcome or media clearing, so they are not part of routine care.
The result may not apply to other infections, such as those from bleb-related or endogenous sources (see endogenous versus exogenous endophthalmitis).
The Organisms
Cultures were positive in about 69 percent of eyes. Gram-positive coagulase-negative staphylococci were the most common, at about 70 percent of positive cultures (see the references).
Gram-negative organisms and Staphylococcus aureus gave worse outcomes, and a few cases were fungal.
Almost all of the isolates were susceptible to vancomycin, and most gram-negative organisms were susceptible to ceftazidime or amikacin.
Endophthalmitis Vitrectomy Study: Visual Outcomes
About 53 percent of all eyes reached 20/100 or better, and 74 percent reached 20/200 or better, in the trial population.
Severe loss occurred in about 5 percent, and outcomes depended on the organism, the starting vision, and the time to treatment.
Changes Since the EVS
- Intracameral antibiotics at the end of surgery cut the rate of endophthalmitis in the ESCRS study (see intracameral antibiotic prophylaxis)
- Small-gauge vitrectomy and widefield viewing make early vitrectomy easier
- Ceftazidime has been replaced by other options in some places, because of retinal toxicity concerns
- Some surgeons now do early vitrectomy at lower thresholds
Endophthalmitis Vitrectomy Study: Practical Use
Examine the patient at once, record the vision, and tap and inject without delay in patients with hand motions or better vision.
Perform an urgent vitrectomy in patients with light perception only vision, and repeat injections when the eye does not improve in 48 hours.
An Example Case
A 74-year-old man has pain and blurred vision three days after uncomplicated cataract surgery.
The cornea is also hazy, there is a hypopyon, the view of the fundus is poor, and acuity is hand motion.
Following the EVS, the retina specialist performs an immediate vitreous tap, injects intravitreal vancomycin and ceftazidime, and sends the samples for culture.
The next day the eye is improving, with the final acuity of 20/40.
Practical Steps in the Clinic
- Do not delay treatment while waiting for a culture
- Take a vitreous sample with a needle or a vitrector, since vitreous gives a higher yield than aqueous
- Inject the antibiotics at once, using the correct doses, and avoid mixing in the same syringe
- Examine the next day, and repeat injections at 48 hours if the eye is not better
Counselling the Patient
Explain that the infection is serious, that treatment works best when started quickly, and that vision usually improves but may not return to the level before surgery.
Review the warning signs for the fellow eye, and discuss the added precautions at the next surgery.
Key Points to Remember
- Hand motion or better: tap and inject
- Light perception only: immediate vitrectomy
- Intravenous antibiotics added nothing in the trial
- Gram-positive organisms dominate, and the outlook is worse with gram-negative infection
Limits of the Study
The trial included only infections after cataract surgery, and did not test the use of intracameral antibiotics.
It was done with older vitrectomy equipment and antibiotics.
Some modern surgeons choose an early vitrectomy at a lower threshold, though the EVS rule remains a useful starting point.
Document what you see
Two smartphone imaging tools built for everyday clinic use — one for the slit lamp, one for the fundus.
From Choroida — the team behind this siteReferences
- Endophthalmitis Vitrectomy Study Group. Results of the Endophthalmitis Vitrectomy Study: a randomized trial of immediate vitrectomy and of intravenous antibiotics for the treatment of postoperative bacterial endophthalmitis. Arch Ophthalmol. 1995;113:1479-1496.
- Han DP, Wisniewski SR, Wilson LA, et al. Spectrum and susceptibilities of microbiologic isolates in the Endophthalmitis Vitrectomy Study. Am J Ophthalmol. 1996;122:1-17.
- Barry P, Cordovés L, Gardner S. ESCRS guidelines for prevention and treatment of endophthalmitis following cataract surgery: data, dilemmas and conclusions. European Society of Cataract and Refractive Surgeons; 2013.
- American Academy of Ophthalmology. Basic and Clinical Science Course, Section 9: Uveitis and Ocular Inflammation. AAO; current edition.
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