EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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E W CORNEA 54 February 2014 smoother than can be obtained in the deep stroma using traditional LASIK flap laser parameters. OCT revealed stromal separation either at or slightly anterior to D escemet's membrane with sporadic small wisps of torn stroma on a smooth bed. Staining showed no ev- idence of endothelial injury. We are now confirming those results with further microscopy of the endothe- lium to be certain it is not damaged. Some additional research re- mains to be done before we would be comfortable trying this in human s ubjects. In addition, minor software modifications will be required to rotate the angle of the passes in an actual treatment. However, these are relatively minor obstacles compared to the technology challenges we have faced in the past, and I am optimistic that human trials will be possible quite soon. Other applications Not only could the mini-bubble technique be a viable substitute for big bubble DALK, bringing us closer to a 100% success rate with DALK, but it may also be useful for Descemet's stripping automated endothelial keratoplasty (DSAEK), w hich is very exciting. To date, laser-assisted DSAEK has not been possible. Instead, eye banks use a microkeratome to pre- pare donor tissue for DSAEK. To achieve the thin grafts that are de- sired, they often have to make two passes of the microkeratome, and the tissue loss rate is high. When a successful graft can be obtained it is not always as smooth or as reliable as one would like, due to variations in the microkeratome cuts. If we could increase the precision and smoothness of DSAEK grafts with the femtosecond laser using this deep lamellar dissection technique, it would be of great value in improv- ing results for patients with posterior corneal dystrophies. EW References 1. Farid M, Steinert RF, Gaster RN, et al. Comparison of penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional blade trephina- tion. Ophthalmology 2009;116(9):1638-43. 2. Farid M, Steinert RF. Deep anterior lamellar keratoplasty performed with the femtosecond laser zigzag incision for the treatment of stro- mal corneal pathology and ectatic disease. J Cataract Refract Surg 2009;35(5):809-13. 3. Steinert RF, Farid M, Garg S, Wade M. Fem- tosecond laser "mini-bubble" deep lamellar dissection for DALK and DSAEK. Poster presentation, Association for Research in Vision and Ophthalmology, May 2013. Editors' note: Dr. Steinert is professor of ophthalmology, professor of biomedical engineering, director of the Gavin Herbert Eye Institute, and chair of ophthalmology, University of California Irvine (UCI). He has financial interests with Abbott Medical Optics, SightLife (Seattle), and Research to Prevent Blindness (New York). Contact information Steinert: steinert@uci.edu www.ahmedvalve.com 800.832.5327 Model M4 Porous Plate We're Changing The Game with our new Model M4 valve. Femtosecond continued from page 52 " Not only could the mini-bubble technique be a viable substitute for big bubble DALK, bringing us closer to a 100% success rate with DALK, but it may also be useful for DSAEK, which is very exciting. " 50-55 Cornea_EW February 2014-DL2_Layout 1 1/30/14 10:41 AM Page 54