Corneal interface contamination during laser in situ keratomileusis
PURPOSE: To measure the rate of corneal interface contamination during laser in situ keratomileusis (LASIK), determine probable sources of the contamination, and evaluate how the cornea reacts to the contamination. SETTING: Department of Ophthalmology, Baqyatallah Hospital, Baqyatallah University, Tehran, Iran METHODS: In this case series, 200 eyes were evaluated for the corneal interface contamination at the end of LASIK. Cultures were taken from the upper and lower eyelid margins and the inferior fornices before surgery and from the corneal interface and the instrument at the end of surgery. Media were cultured at 37 degrees C for 14 days under aerobic and anaerobic conditions. Bacteria from positive cultures were isolated and identified by biochemical procedures to determine the species of the organisms. RESULTS: The rate of contamination was 24.5%. The most common retrieved organism was Staphylococcus epidermidis (43 cases, 87.7%). None of the contaminated or noncontaminated cases developed corneal ulcers; however, 2 eyes developed diffuse lamellar keratitis. CONCLUSION: The corneal stroma has the ability to clear introduced microorganisms during LASIK.