Reply: Bevel-up versus bevel-down phacoemulsification tip
First, we did not have access to real-time optical coherence tomography for determining the exact position of the phaco tip intraoperatively; however, as we mentioned in the discussion section of our article, in the bevel-down position, the surgeon must place the phaco tip closer to the surface of the lens for better occlusion during heminucleus chopping and particle emulsification. Thus, phacoemulsification occurs closer to endothelial cells and causes more damage to these cells. In phacoemulsification with the phaco needle in the bevel-up position, the phaco tip can be positioned deeply and parallel to the lens tissue, with stable occlusion far from the endothelial cells.
Second, we unfortunately did not measure the total surgical time and the amount of irrigation fluid. However, the surgeon in our study is very experienced and fast in performing phaco with the bevel-down technique and his first choice for doing any technique of phaco surgery is the bevel-down position.
Finally, we used the small-field noncontact specular microscope model with automatic focusing and digital image capture that specified in the guidelines for performing specular microscopy in the U.S. Food and Drug Administration clinical trials.1 Also, the same operator performed all specular microscopy so our study was not confounded by interoperator variability.
© 2012 by Lippincott Williams & Wilkins, Inc.
1. McCarey BE, Edelhauser HF, Lynn MJ. Review of corneal endothelial specular microscopy for FDA clinical trials of refractive procedures, surgical devices, and new intraocular drugs and solutions. Cornea. 2008;27:1-16.