Trends in Ophthalmic Microbiology - Perspectives from Dr. Francis Mah
Trends in Ophthalmic Microbiology - Perspectives from Dr. Francis Mah
In a conversation with Dr. Parag Majmudar, Dr. Francis Mah discusses the current thinking in ocular microbiology in the cataract and refractive setting. Methicillin-resistant S. aureus (MRSA) is now the leading cause of post-LASIK infection. Data from an ASCRS cornea clinical committee survey in 2001, found that 48% post-lasik infections were caused by atypical mycobacteria. With use of moxifloxacin and gatifloxacin, those rates have gone down. By 2004, 60% of infections were S. aureus and less than 5% mycobacteria. This year’s data show that MRSA is the #1 culprit. This follows the trend seen throughout ophthalmology; methicillin resistance being seen more frequently in endophthalmitis and keratitis. Dr. Mah suggests that standard of care should be that LASIK and cataract patients are treated for pre-existing dry eye. Lid draping is key since the normal flora is often the source of contamination. Povidone-iodine 5% can be applied to the eyes of cataract patients. Avoid povidone-iodine in the eyes of LASIK patients, but apply it generously to the lids and lashes. Meticulous sterile surgical technique is key. For LASIK, use the 4th generation fluoroquinolones. IQUIX (1.5% levofloxacin) has shown excellent penetration into ocular tissues. Dr. Mah then outlines his own recommendations for post-op dosing of both LASIK and cataract patients. He then discusses the endophthalmitis delay in clear corneal incisions, suggesting that longer use of anti-infectives may be indicated. Another controversy is the use of intra-cameral anti-infectives. This was highlighted in several recent European studies. Dr. Mah currently does not use intra-cameral antibiotics for prophylaxis though he does see the logic. His concern is of the risk of toxic anterior segment syndrome (TASS) and that long-term safety studies on the use of intra-cameral injections have not been done.