Purpose. To compare the effect of 60？kHz and 150？kHz femtosecond (FS) laser on the corneal stromal bed surfaces (SBS). Methods. Sixteen human donor corneal tissues unsuitable for transplantation were used. Anterior and posterior lamella was obtained using 60？kHz and 150？kHz FS laser. A standard depth of 400？μm was set for anterior lamellar keratoplasty (ALK) and endothelial lamellar keratoplasty (ELK). The quality and smoothness of the SBS post-FS laser dissection were graded for statistics. Results. No intraoperative complications were found. The side cuts were straight, and the SBS appeared smoother in cuts obtained using 150？kHz. The average values of the SBS quality of the anterior lamellar cut were found to be 2.25 (±0.28) for 60？kHz and 3.125 (±0.25) for 150？kHz ( ). Whereas, 2 (±0.4) for 60？kHz and 2.75 (±0.28) for 150？kHz ( ) was the quality observed in endothelial cuts. No significant difference was found between anterior and posterior cuts performed using the same FS laser (60？kHz or 150？kHz) ( ). Conclusions. The 60？kHz and 150？kHz FS lasers are equally effective in performing lamellar dissection for ALK and ELK. 150？kHz FS laser allows a tighter spot and layer separation which creates a slightly smoother SBS. 1. Introduction Corneal lamellar keratoplasty (LK) is a surgical technique that allows preserving healthy portions of the cornea while selectively replacing the dysfunctional layers. The outcome of LK has also shown improvements of the procedure by decreasing surgical risk, enhancing healing process and quick rehabilitation as compared to penetrating keratoplasty (PK) [1]. Since the last decade, the femtosecond (FS) laser technology has been developed to perform laser assisted in situ keratomileusis (LASIK) refractive surgery. It reduced the complication rate due to LASIK flap creation, improved the predictability of flap dimensions, and improved the quality of the optical surface, compared to microkeratome surgery [2–8]. The reliability and safety have been evaluated using IntraLase FS (iFS, Abbott, Irvine, CA, USA) laser which have already been verified extensively for LASIK and more recently for endothelial lamellar keratoplasty (ELK) [9, 10]. The FS uses pulses to create corneal resection. The quality of the surfaces obtained is determined by programmable parameters like the laser spot and layer separation and the energy delivered per pulse. It was therefore evaluated that, with closer spots, the energy required for the cuts is less and with less energy surface gets smoother [2]. The early stage of this technology allowed the firing
References
[1]
H. Mehta, “Newer trends in lamellar keratoplasty,” Journal of the Bombay Ophthalmologists, vol. 14, no. 2, pp. 19–24, 2005.
[2]
M. A. Sarayba, T. S. Ignacio, P. S. Binder, and D. B. Tran, “Comparative study of stromal bed quality by using mechanical, IntraLase femtosecond laser 15- and 30-kHz microkeratomes,” Cornea, vol. 26, no. 4, pp. 446–451, 2007.
[3]
M. A. Sarayba, T. S. Ignacio, D. B. Tran, and P. S. Binder, “A 60？kHz IntraLase femtosecond laser creates a smoother LASIK stromal bed surface compared to a zyoptix XP mechanical microkeratome in human donor eyes,” Journal of Refractive Surgery, vol. 23, no. 4, pp. 331–337, 2007.
[4]
Y. J. Jones, K. M. Goins, J. E. Sutphin, R. Mullins, and J. M. Skeie, “Comparison of the femtosecond laser (IntraLase) versus manual microkeratome (Moria ALTK) in dissection of the donor in endothelial keratoplasty: initial study in eye bank eyes,” Cornea, vol. 27, no. 1, pp. 88–93, 2008.
[5]
P. S. Binder, “Flap dimensions created with the IntraLase FS laser,” Journal of Cataract and Refractive Surgery, vol. 30, no. 1, pp. 26–32, 2004.
[6]
L. T. Nordan, S. G. Slade, R. N. Baker, C. Suarez, T. Juhasz, and R. Kurtz, “Femtosecond laser flap creation for laser in situ keratomileusis: six-month follow-up of initial U.S. clinical series,” Journal of Refractive Surgery, vol. 19, no. 1, pp. 8–14, 2003.
[7]
I. Ratkay-Traub, T. Juhasz, C. Horvath et al., “Ultra-short pulse (femtosecond) laser surgery: initial use in LASIK flap creation,” Ophthalmology Clinics of North America, vol. 14, no. 2, pp. 347–355, 2001.
[8]
G. D. Kymionis, V. P. Kankariya, A. D. Plaka, and D. Z. Reinstein, “Femtosecond laser technology in corneal refractive surgery: a review,” Journal of Refractive Surgery, vol. 28, no. 12, pp. 912–920, 2012.
[9]
Y. Y. Y. Cheng, E. Pels, and R. M. M. A. Nuijts, “Femtosecond-laser-assisted Descemet's stripping endothelial keratoplasty,” Journal of Cataract and Refractive Surgery, vol. 33, no. 1, pp. 152–155, 2007.
[10]
P. M. Phillips, L. J. Phillips, H. A. Saad et al., “Ultrathin" DSAEK tissue prepared with a low-pulse energy, high-frequency femtosecond laser,” Cornea, vol. 32, no. 1, pp. 81–86, 2013.
[11]
C. Monterosso, A. Fasolo, L. Caretti, G. Monterosso, L. Buratto, and E. B？hm, “Sixty-kilohertz femtosecond laser-assisted endothelial keratoplasty: clinical results and stromal bed quality evaluation,” Cornea, vol. 30, no. 2, pp. 189–193, 2011.
[12]
Y. Y. Y. Cheng, S. J. Kang, H. E. Grossniklaus et al., “Histologic evaluation of human posterior lamellar discs for femtosecond laser descemet's stripping endothelial keratoplasty,” Cornea, vol. 28, no. 1, pp. 73–79, 2009.
[13]
Y. Y. Y. Cheng, J. S. A. G. Schouten, N. G. Tahzib et al., “Efficacy and safety of femtosecond laser-assisted corneal endothelial keratoplasty: a randomized multicenter clinical trial,” Transplantation, vol. 88, no. 11, pp. 1294–1302, 2009.
[14]
J. S. Mehta, R. Shilbayeh, Y. M. Por, H. Cajucom-Uy, R. W. Beuerman, and D. T. Tan, “Femtosecond laser creation of donor cornea buttons for Descemet-stripping endothelial keratoplasty,” Journal of Cataract and Refractive Surgery, vol. 34, no. 11, pp. 1970–1975, 2008.
[15]
S. H. Yoo, G. D. Kymionis, A. Koreishi et al., “Femtosecond laser-assisted sutureless anterior lamellar keratoplasty,” Ophthalmology, vol. 115, no. 8, pp. 1303–1307, 2008.
[16]
M. A. Shousha, S. H. Yoo, G. D. Kymionis et al., “Long-term results of femtosecond laser-assisted sutureless anterior lamellar keratoplasty,” Ophthalmology, vol. 118, no. 2, pp. 315–323, 2011.
[17]
O. Suwan-Apichon, J. M. G. Reyes, N. B. Griffin, J. Barker, P. Gore, and R. S. Chuck, “Microkeratome versus femtosecond laser predissection of corneal grafts for anterior and posterior lamellar keratoplasty,” Cornea, vol. 25, no. 8, pp. 966–968, 2006.
[18]
S. Sikder and R. W. Snyder, “Femtosecond laser preparation of donor tissue from the endothelial side,” Cornea, vol. 25, no. 4, pp. 416–422, 2006.
[19]
Y. Y. Y. Cheng, E. Pels, and R. M. M. A. Nuijts, “Femtosecond-laser-assisted Descemet's stripping endothelial keratoplasty,” Journal of Cataract and Refractive Surgery, vol. 33, no. 1, pp. 152–155, 2007.
[20]
H. K. Soong, S. Mian, O. Abbasi, and T. Juhasz, “Femtosecond laser-assisted posterior lamellar keratoplasty: initial studies of surgical technique in eye bank eyes,” Ophthalmology, vol. 112, no. 1, pp. 44–49, 2005.
