ASCRS survey results: better diagnosis of infections but incidence of infections increasing

The American Society of Cataract and Refractive Surgery (ASCRS) survey results for 2008 pointedout some changing trends in infectious keratitis after LASIK and PRK compared with previoussurveys conducted in 2002 and 2005, said Terry Kim, MD.

In 2008, a total of 14 surgeons reported 19 cases of infectious keratitis after LASIK and PRKin 2007. "That represented a larger number of cases compared with previous years, whichpresented with 1 week after surgery, Dr. Kim commented. He is associate professorophthalmology, Duke University School of Medicine, Raleigh, NC.

Dr. Kim also reported that there has been a marked increase in the incidence of atypicalmycobacteria causing those infections over the past 7 years. However, he noted, the past twosurveys have shown an increase in Staphylococcus organisms causing those infectionsafter LASIK and PRK. In the 2007 survey, methicillin-resistant Staphylococcusaureus (MRSA) emerged as the most common organism causing these infections after LASIK andPRK. Of three MRSA infections that occurred, two developed in health care workers.

The survey results also showed that no case of atypical mycobacteria infectious keratitisdeveloped in any patient who received a fourth-generation fluoroquinolone as prophylaxis inboth the 2005 and 2008 surveys.

Importantly, diagnosis has improved greatly. "The infections are presenting earlier and thevisual prognosis is improving," Dr. Kim said.

In 2007, 84% of cases of infectious keratitis were diagnosed at the initial presentation incontrast to 2004 when most cases where not diagnosed at the initial presentation, Dr. Kimnoted. That resulted from the fact that most surgeons are now obtaining scrapings forculturing.

The uncorrected visual acuity results in 2008 compare favorably to the previous surveys. Manypatients retained good vision after treatment. Only two patients required keratoplasty in 2007compared with three in 2004 and 10 in 2001 and earlier.

More infections were found to occur in association with a microkeratome compared with thefemtosecond laser likely because of the single-use femtosecond laser cone and less trauma tothe epithelium.