Fifth Generation Femtosecond Laser Flap Thickness

1. Mohamed A Guenena, MD Helga P Sandoval, MD, MSCR, Kerry D Solomon, MD Magill research center for vision correction Storm Eye Institute Medical University of South Carolina Fifth Generation Femtosecond Laser Flap Thickness Financial Disclosure: None of the authors has any financial interest in any product mentioned herein Mohamed A. Guenena: None Helga P. Sandoval: Alcon Laboratories, Inc. - D; Allergan, Inc. - D; Abbott Medical Optics - D Kerry D. Solomon: Alcon Laboratories, Inc. - A,C,D; Allergan, Inc. - A,C,D; Abbott Medical Optics - A,C,D; Advanced Vision Research -  A,C,D; Bausch & Lomb, Inc. -  A,C,D; Eyemaginations -  A,C,D; QLT, Inc. -  A,C,D

2. To assess the accuracy and reproducibility of flap thickness created by the fifth generation femtosecond laser using: • Intraoperative pachymetry • Postoperative anterior segment OCT ASCRS 2009 Purpose

3. Prospective, unmasked study • 24 eyes of 12 patients • Had primary LASIK surgery • Flaps created with the new 5th generation femtosecond Laser (iFS Advanced Femtosecond Laser, Abbot Medical Optics ) • Attempted Flap depth • 100 microns in 4 eyes • 110 microns in 20 eyes • Assessment: • Intraoperative pachymetry • Postoperative anterior segment Fourier-domain optic coherence tomography (OCT) on a subgroup of patients at an average of 3 month • The SAS system software was used to analyze the results ASCRS 2009 MethodS

4. 2 cross scans were used to measure each flap (Figure 1) • The cross scan setting entails 2x1024 A scans (8 scans in each directions are then averaged) • The LASIK flap was identified by increased reflectivity at the flap-stromal interface. then the cursor was moved manually to the interface and measurements were recorded. • On each line of the cross scan, the thickness was calculated at four points ( Figure 2) • A 2.5 mm left to the midline • B 1 mm left to midline • C 1 mm right to midline • D 2.5 mm right to midline ASCRS 2009 OCT Settings: A B C D Line 2 Line 3 Line 4 Line 1 Fig. 2 Fig. 1

5. Pre and Postoperative Data • Intraoperative Pachymetry was done by subtraction method ASCRS 2009 ResULTS

6. ASCRS 2009 OCT picture showing the four points measurements for a single line scan in a patient who had a 110 µm flap

7. ASCRS 2009 OCT ReSuLTS • Overall flap thickness per group • Comparing the consistency of the flap thickness at different points in the 110 µm group in all line scans

8. Comparing the flap thickness by lines for the 110µm group ASCRS 2009 OCT ReSuLTS

9. The new fifth generation femtosecond laser shows • High consistency of flap thickness • High reproducibility of flap thickness • Accurate flap thickness predictability • The flaps are uniform at different points ASCRS 2009 Conclusion

10. ASCRS 2009

11. ASCRS 2009 Thank you