1. Retrospective Comparison of Flap Complications in LASIK Using Hansatome Mechanical Microkeratome and Femtosecond Laser Majid Moshirfar, MD Jeffrey P Gardiner, BS Joshua A Schliesser, BS Ladan Espandar, MD Vahid Feiz, MD Mark D Mifflin, MD Joann C Chang, MD The John A. Moran Eye Center All authors listed have no financial interest in the materials discussed.

2. Purpose To compare the incidence of flap complications of laser-assisted in situ keratomileusis (LASIK) using the Hansatome© microkeratome (Bausch & Lomb, Rochester, NY) and IntraLase™ FS60 laser (Abbott Medical Optics, Santa Ana, CA) Setting: John A. Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA.

3. Methods Retrospective, comparative, interventional case series evaluating flap complication rate during the initial eighteen months of experience with the Hansatome microkeratome and IntraLase FS60 laser Microkeratome group: 896 eyes underwent the Hansatome© microkeratome between February 2001 to July 2002 IntraLase group: 902 eyes of patients who underwent the IntraLase™ FS60 laser between August 2006 to January 2008

4. Methods All operations were performed by two surgeons (Majid Moshirfar, Mark Mifflin) at the John A. Moran Eye Center. All patients included in this study were deemed safe to undergo LASIK according to the FDA guidelines found at http://www.fda.gov/cdrh/lasik/lasers.htm. http://www.fda.gov/cdrh/lasik/lasers.htm Approval for the current study was granted by an Institutional Review Board (IRB) at the University of Utah.

5. Results Intraoperative Complications: –Major Epithelial Defect/Sloughing (break or loose epithelium greater than 2 x 2 mm) 23 eyes (2.6%) in the Hansatome group 5 eyes (0.6%) in the IntraLase group –Incomplete Flap 8 eyes (0.9%) in the Hansatome group due to suction loss. 10 eyes (1.1%) in the IntraLase group due to suction loss. –6 were during the lamellar cut. 4 were incomplete side cuts. –Button Hole 7 eyes (0.8%) in the Hansatome group 3 eyes (0.3%) in the IntraLase group via vertical gas breakthrough

6. Results Intraoperative Complications: –Torn Flap 4 eyes (0.4%) in the Hansatome group 4 eyes (0.4%) in the IntraLase group –All occurred at the hinge site. –Decentered Flap – if a 6 mm ablation zone was not attainable 5 eyes (0.6%) in the Hansatome group 1 eye (0.1%) in the IntraLase group –Anterior Chamber Gas Bubble – 3 eyes (0.3%) in the IntraLase group. –The bubbles interfered with pupillary tracking in 2 eyes

7. Results Postoperative complications, occurring within six weeks of the original procedure, included: –Dislocated Flap 22 eyes (2.5%) on postoperative day (POD) one in the Hansatome group 10 eyes (1.1%) on POD 1 in the IntraLase group –Epithelial In-growth 2 eyes (0.2%) in the Hansatome group 1 eye (0.1%) in the IntraLase group –Diffuse Lamellar Keratitis (DLK) 54 eyes (6.02%) in the Hansatome group –52 eyes were at stage I and II. 2 eyes progressed to stage III 96 (10.6%) in the IntraLase group –All eyes remained in stage I and II.

8. Results Postoperative complications: –Central Toxic Keratopathy (CTK) 2 eyes (0.2%) of the same patient, in the Hansatome group No cases in the IntraLase group –Transient Light Sensitivity Syndrome (TLSS) 4 eyes from two patients presented with photophobia 3-4 weeks postoperatively in the IntraLase group only. Minor epithelial defects, subconjunctival hemorrhages, difficulty lifting the flap, and thin or thick flaps were not included as part of the analysis. Final BSCVA in the cases with complication were not statistically significant between the two groups (Table 1)

9. Table 1. Final Visual Outcomes and Incidence of Complications Hansatome (n=896) IntraLase (n=902) Flap-related Complication Final BSCVA n (%) ≤ 20/20≤ 20/40 n (%) ≤ 20/20≤ 20/40 Intraoperative Buttonhole or Gas Breakthrough7 (0.8)473 (0.3)13 Torn Flap4 (0.4)34 44 Decentered Flap5 (0.6)451 (0.1)11 Gas Bubble in AC3 (0.3)33 Postoperative Epithelial Ingrowth2 (0.2)021 (0.1)11 CTK2 (0.2)02 TLSS4 (0.4)44 BSCVA = best spectacle-corrected visual acuity, DLK = diffuse lamellar keratitis, CTK = central toxic keratopathy, TLSS = transient light sensitivity syndrome

10. Results A total complication rate: –14.17% (n=127) was observed in the Hansatome group –15.19% (n=137) was observed in the IntraLase group (p=0.5437). The intraoperative flap complication rate: –5.25% (n=47) for Hansatome –2.88% (n=26) for IntraLase (p=0.0111) The postoperative flap complication rate: –8.93% (n=80) for Hansatome group –12.31% (n=111) for IntraLase (p=0.0201)

11. Table 1: Total intraoperative and postoperative complication rates. * = statistically significant Table 2: Incidence of major epithelial defect/sloughing, incomplete flap, dislocated flap, and DLK. * = statistically significant DLK = diffuse lamellar keratitis

12. Discussion The Hansatome group had a statistically greater # of intraoperative complications –Mostly attributed to major epithelial defects/sloughing The IntraLase group had a statistically greater # of postoperative complications –Primarily due to DLK stages I and II We did not show a significant difference in the total complication rate when comparing the Hansatome microkeratome (14.17%) and the IntraLase laser (15.19%)