1. The authors have no financial interest
Emory University
Analysis of Thin Microkeratome Flap Architecture Using Fourier-Domain OCT
Karolinne Maia Rocha, M.D., Ph.D
J. Bradley Randleman, M.D.
R. Doyle Stulting, M.D., Ph.D.
The authors have no financial interest

2. Purpose
To assess the corneal architecture and the reproducibility of laser in situ keratomileusis (LASIK) flap thickness created by a mechanical microkeratome using a Fourier-domain optical coherence tomography (OCT).

3. Methods Prospective study
58 LASIK flaps (Amadeus II - Ziemer,140µm head, 9.0 and 9.5mm suction rings, ML7090CLB - Med-Logics blades)
Intraoperative ultrasound (US) pachymetry flap thickness measurement
Fourier-domain OCT (Optovue RTVue-100) flap morphology evaluation at 2 weeks postoperatively

4. Methods The flap thickness was assessed twice at :
Fourier-domain OCT Analysis
The flap thickness was assessed twice at :
10 points across the central 6-mm of the corneal apex (horizontal and vertical meridians)
1.5-mm from the edge of the flap superior and inferiorly

5. Time Domain vs Fourier Domain
Visante OCT 1000 (Carl Zeiss)
2000 A scans/second
depth resolution of 18 µm
transverse resolution of 60 µm
Scan beam wavelength: 1310 nm
Exposure power at pupil 5 W
The scan range is 3 mm in depth to 10 mm in transverse direction.
RTVue device (Optovue)
26,000 A scans/second
depth resolution of 5 µm
transverse resolution of 15 µm
Scan beam wavelength: 840±10 nm
Exposure power at pupil 750 W
Cornea–Anterior Module (CAM)
additional software on the device,
The CAM L lens allows 6 x 6-mm
scans of the cornea

6. Time Domain vs Fourier Domain

7. OCT - Horizontal

8. OCT - Horizontal

9. Results Postoperative OCT = 111.7±11µm
Intraoperative US pachymetry = 107.2±14µm
Postoperative OCT = 111.7±11µm
No statistically significant difference (p=0.07)
The OCT measurements showed a planar flap
SD across the flap = 4.9µm,
SD for the 6-mm central measurements = 11µm
SD range across the flap= 2 to 9µm

10. Conclusion
The Amadeus II microkeratome with Med-Logics blades created regular, planar flaps as demonstrated by the Fourier-domain OCT.
Central flap thickness measured by intraoperative US pachymetry was comparable to that measured 2 weeks postoperative by OCT.

11. Thank you