Acute-onset endophthalmitis: what are the risk factors?

October 15, 2005

Montr?al—Acute-onset endophthalmitis is an uncommon event after cataract surgery in the new millennium (the rate equals 0.04%). Possible risk factors include intraoperative complications, relative immune compromise, use of lidocaine 2% gel before povidone-iodine preparation, and an inferior location of the incision, according to Harry W. Flynn Jr., MD, at the American Society of Retina Specialists meeting.

In the study headed by John Miller, MD, investigators set out to determine retrospectively the incidence of endophthalmitis at Bascom Palmer Eye Institute, where approximately 3,000 cataract operations are performed annually, said Dr. Flynn, professor, department of ophthalmology, Bascom Palmer Eye Institute, University of Miami.

Since the start of new millennium, 15,920 cases have been performed over the 5 years between January 2000 and January 2005; of those, seven patients had positive cultures or clinically suspected endophthalmitis. In all of these cases, povidone-iodine was applied to the conjunctiva and lid margins and all patients underwent surgery by ophthalmologists at the Bascom Palmer Eye Institute.

Risk factors for the development of endophthalmitis covered a number of areas. Relative immune compromise was a risk factor; four patients had diabetes mellitus, and one patient had polymyalgia rheumatica. In two of the seven cases of endophthalmitis, lidocaine jelly was applied to the conjunctiva before the prep with povidone-iodine, which may have negated the effect of the povidone-iodine. Intraoperatively, 57% of the patients had complications; three of the four had vitreous loss and one of the four had repeated iris prolapse during the cataract surgery. Perioperatively, many of these patients were treated with fluoroquinolones; two endophthalmitis isolates displayed resistance to the fourth-generation fluoroquinolones. In this large series of more than 15,000 cataract operations, antibiotics were not used in the irrigation fluid during surgery.

In addition, six of the seven patients with endophthalmitis had the infection in the right eye and the surgery was performed by surgeons who were right-handed. The wounds were made slightly inferiorly by right-handed surgeons; thus the wound may approximate the tear lake and may allow the organisms to enter the wound. Regarding wound construction, no eyes had wound leakage at the time of the diagnosis of endophthalmitis. Three of seven eyes underwent a vitrectomy to address the endophthalmitis, but no suture was needed for the cataract wound during the vitrectomy. The IOP levels 1 day after cataract surgery ranged from 11 to 25 mm Hg and no hypotony developed, Dr. Flynn explained.

"Vitreous cultures were positive in 71% of the eyes with endophthalmitis. The organisms that were identified were coagulase-negative staphylococcus in four cases, streptococcus in one case, and two cases were culture negative," Dr. Flynn reported.

Four of the cases achieved 20/40 or better visual acuity. All patients were treated with intravitreal vancomycin, ceftazidime, and dexamethasone. Three of the eyes also underwent pars plana vitrectomy.