[1] Moorfields Eye Hosp, Dept Corneal Surg, London EC1V 2PD, England
[2] Heart England Natl Hlth Serv Fdn Trust, Birmingham Heartlands Hosp, Dept Corneal Surg, Birmingham, W Midlands, England
[3] Johns Hopkins Univ Hosp, Wilmer Eye Inst, Baltimore, MD 21287 USA
[4] Singapore Natl Eye Ctr, Dept Corneal Surg, Singapore, Singapore
[5] Cornea Res Fdn Amer, Indianapolis, IN USA
[6] Price Vis Grp, Indianapolis, IN USA
[7] Univ Calif Los Angeles, Jules Stein Eye Inst, Los Angeles, CA 90024 USA
[8] Villa Serena Hosp, Dept Corneal Surg, Forli, Italy