Dr. Olson

During the American Society of Cataract and Refractive Surgery annual meeting, Dr. Olson presented 10-year results of a quality control program of the John A. Moran Eye Center, University of Utah School of Medicine, of which he is professor, chairman, and chief executive officer. The results are based on a prospective review of more than 30,000 cataract extractions.

Wound leaks

The overall incidence of endophthalmitis in clear corneal cases during the first 5 years of the 10-year study was approximately one in 500, he said. These first 5 years were extensively studied, and the results were published in the Journal of Cataract and Refractive Surgery (2005; 31:735-741). Approximately 1,200 of the 15,254 extractions studied in the article were corneoscleral, and no cases of endophthalmitis were found among those patients.

Dr. Olson and his colleagues conducted a multivariate analysis, which included a random cohort survey of 10% of these 15,254 cases to create a control group.

The multivariate analysis showed that in clear corneal cases, a wound leak on the first postoperative day increased the risk of endophthalmitis 44 times compared with a surgery in which no leak occurred (p < 0.001).

"Look at a leaky wound on the first postoperative day, and you can see the whole tear film going in and out of the eye every time the patient blinks. It's gross contamination," Dr. Olson said.

A capsular breakage or zonular tear increased the odds of endophthalmitis 17-fold (p = 0.001), he added.

"If you get bacteria into the vitreous versus into the anterior chamber only, your odds of endophthalmitis increase substantially," Dr. Olson said. "You don't have to throw out clear corneal surgery, as long as you're very careful about your wounds and how they're created. Suture when in doubt."

Antibiotic selection

Antibiotics perioperatively and on the day of surgery also are important steps in preventing endophthalmitis, he said.

Delaying topical antibiotics to postoperative day 1 increased the risk of endophthalmitis 13.7-fold compared with using topical or subconjunctival antibiotics during the surgery and on the same day as the surgery (p = 0.005), Dr. Olson said.

When selecting an antibiotic, he said to remember to consider its intraocular penetration. According to Dr. Olson, patients in this study who received ciprofloxacin ophthalmic drops (Ciloxan, Alcon Laboratories) were 5.3 times more likely to develop endophthalmitis than patients who received ofloxacin (Ocuflox, Allergan) (p = 0.014).

"Our overall rate of endophthalmitis was one in 500, but it was one in 200 in cases in which topical ciprofloxacin was used," he said. "Ciprofloxacin does not penetrate ocular tissues well, and it's difficult to achieve therapeutic levels in the anterior chamber with it."

The fourth-generation fluoroquinolones, gatifloxacin ophthalmic solution (Zymar, Allergan) and moxifloxacin ophthalmic solution (Vigamox, Alcon Laboratories), which were introduced in 2003, have good intraocular penetration and have served to reduce the rate of endophthalmitis to one in 2,000 (p = 0.001) in patients who receive them perioperatively or on the day of surgery, according to Dr. Olson.

"I can't tell you which prophylactic antibiotic approach is better—topical, intracameral, or subconjunctival—and given that the incidence ranges from one in 500 to one in 2,000, the number of patients needed to design a study to analyze which method is more effective would be daunting," he said. "The evidence is very clear that you need the antibiotic in place at therapeutic levels in the anterior chamber the day of the surgery."

Effective technique

In regard to TASS, Dr. Olson said that standard steam sterilization following consistent protocols still is an effective instrument sterilization technique, and no evidence exists that "long-cycle" steam sterilization is superior in preventing the syndrome.

"TASS was extremely rare and episodic in our 10-year study of more than 30,000 patients," he said. "Its occurrence was in the range of one in 5,000 to one in 10,000. Even the very rare cases . . . did not seem to be related in any way to our standard steam sterilization cycle, which we maintained in a protocol-driven way. We're very confident that TASS can be kept to a minimal level using a standard steam sterilization protocol."