Proper Positioning of the Plume Evacuator in the VISX Star 3 Excimer Laser Minimizes Central Island Formation in Patients Undergoing LASIK

Abstract

Abstract: : Purpose:To identify risk factors in a series of patients who developed steep central islands after LASIK surgery. Methods:Case reports, review of medical literature and analysis of corneal topographies. Results:We analyzed the outcomes of 84 eyes of 44 patients who underwent LASIK surgery using the VISX Star 3 excimer laser from December 2000 to Jan. 2001. Mean pre-operative spherical equivalent was -6.64 D +/- 2.6 D (range -1.00 to -12.12 diopters). Four eyes developed steep central islands detected on corneal topography 1 week after surgery with resultant residual myopia or myopic astigmatism. Mean pre-operative spherical equivalent of these eyes is -9.27 D +/- 2.29D. Complete resolution of central islands occurred in 3 of 4 eyes within 6 months after LASIK surgery and only one eye had a loss of one line of BCVA. Wavefront analysis of corneal topography showed improvement of point spread function in 2 eyes with resolution of the central islands. The VISX Star 3 excimer laser is equipped with a vacuum aspirator; inspection of this accessory showed the nozzle of the aspirator was abnormally positioned during the time surgeries were performed in these eyes. After correction of this problem, there were no further problems with steep central islands at our institute. Conclusion:Patients who have a higher treatment may have an increase risk of developing central islands after LASIK surgery due to vortex dynamics of the laser plume or change in corneal hydration. Proper positioning of the vacuum aspirator of the VISX Star 3 excimer laser is vital in minimizing central island formation.

Keywords: 545 refractive surgery: complications • 547 refractive surgery: corneal topography • 548 refractive surgery: LASIK