September 2011

 

CATARACT

 

ASCRS Cataract Clinical Committee publishes endophthalmitis white paper


by Enette Ngoei EyeWorld Contributing Editor
     

Cataract surgeons now have a definitive review of treatment and prevention of endophthalmitis

An example of endophthalmitis 2 days after uncomplicated phaco. A layered hypopyon and some corneal edema due to elevated IOP from the endophthalmitis are visible. The organism was MRSA Source: Sonia Yoo, M.D.

Since the idea was first put forth by Sonia Yoo, M.D., Bascom Palmer Eye Institute, University of Miami, in April 2010, members of the ASCRS Cataract Clinical Committee have been combing through all the available peer-reviewed literature and publications on endophthalmitis. Their hard work has culminated in a definitive white paper on the treatment and prevention of endophthalmitis, published in the September issue of the Journal of Cataract and Refractive Surgery.

The extensive review includes literature from the U.S., Europe, and Asia, according to Nick Mamalis, M.D., John A. Moran Eye Center, University of Utah, Salt Lake City.

Dr. Yoo explained the impetus for the study. "I think we've all noticed that there's been a change in the spectrum of infection that we've seen in terms of the micro-organisms causing the infections. We've seen a shift over the last decade in the types of organisms that are causing endophthalmitis. In particular, we've noticed at Bascom Palmer an increase in the incidence of methicillin-resistant organisms. We've seen that not only in endophthalmitis but also in corneal ulcers and post-refractive infections as well."

The review summarizes the information that's out there and tries to make sense of conflicting literature, Dr. Yoo said.

One example of that is the use of antibiotics, in particular, prophylactic topical antibiotics pre-op, she said. There's been a bit of a shift in the types of antibiotics that are used, when they are used, and for how long, she explained, and it seems like there still isn't solid evidence that the use of pre-op topical antibiotics decreases the rate of post-cataract endophthalmitis. Based on the literature and surveys of practice patterns, the use of antibiotics after surgery has become the standard of care, but it's still controversial whether it actually decreases the risk of bacterial endophthalmitis, Dr. Yoo said.

That's because the risk of endophthalmitis is so low that to do a controlled study will take many eyes, and it needs to be done in a very controlled setting, she explained.

Committee chair and driving force behind the monumental effort, Mark Packer, M.D., clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, said, "Obviously it's a high priority for surgeons to prevent infections; they're devastating and they can turn a wonderful result into a terrible result."

He continued, "We like to think we know how to prevent infections, but what we don't know is much bigger than what we know, and I think that's the take-home message from this paperthat there's a lot we don't know."

The one thing that everyone agrees on is that using 5% povidone-iodine prep works, Dr. Packer said. Other than that, there aren't any good comparisons among different protocols and regimens, he said. Even the endophthalmitis study undertaken by the European Society of Cataract & Refractive Surgeons, which was a huge effort, didn't give a definitive answer, Dr. Packer said.

Use of intracameral antibiotics

However, looking at the situation today with the evidence available, it certainly is appealing to believe that the use of intracameral antibiotics, especially in a timed-release form, which maintains a high concentration inside the eye during the post-op period, would be a great thing, Dr. Packer said.

"I think everyone believes that it's bugs inside the eye that cause the damage so we should put antibiotics inside the eye. There's hesitancy to do that especially in the United States because we don't have an approved antibiotic to put inside the eye," he said.

This is an issue that goes to off-label use and the role of the FDA because it's almost impossible to do a study that would show effectiveness of an intracameral antibiotic for the prevention of endophthalmitis as the incidence is so low; it would take a huge number of subjects, perhaps a quarter of a million, to do a study like that, Dr. Packer said.

A commercial preparation would alleviate the fears that "home-brewed" intracameral antibiotics can cause TASS or other significant problems, he added.

Growing resistance

The review found mounting evidence that there are more resistant organisms such as methicillin-resistant staphylococcus aureus and staphylococcus epidermidis, which are becoming bigger culprits in terms of causative organisms, Dr. Yoo said.

"I think the main conclusion is that we don't have the definitive recommendation on what is the best way to prevent endophthalmitis. I wish we could say, 'Here's what you could do, let's make it easy,'" Dr. Packer said. "What we have is a series of suggestions and the recognition that a variety of different approaches are probably valid, but we don't have a way to determine what the best one is," he said.

Editors' note: Drs. Mamalis, Packer, and Yoo have no financial interests related to this article.

Contact information

Mamalis: 801-581-6586, nick.mamalis@hsc.utah.edu
Packer: 541-687-2110, mpacker@finemd.com
Yoo: 305-326-6322, syoo@med.miami.edu

ASCRS Cataract Clinical Committee publishes endophthalmitis white paper ASCRS Cataract Clinical Committee publishes endophthalmitis white paper
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