1. No financial interest for all authors
Evaluation of the Intralase Femtosecond Laser Efficiency in LASIK Flap Creation
Mounir A. Khalifa, MD
Michael Rizman, MD.
Waleed Allam, MD
No financial interest for all authors

2. This study aimed at evaluation of the visual and refractive outcomes of wavefront-guided LASIK using the IntraLase femtosecond laser for flap creation.
The study was conducted at Tufts University School of Medicine, Boston, Massachusetts, USA and included 117 eyes of 63 patients with myopia with or without astigmatism.

3. Preoperative statistical analysis
Table 1: Patients’ age, preoperative refraction, and visual acuity data.
Minimum
Maximum
Mean
Std. Deviation
Age 22 57
35.90
8.718
LogMAR UCVA
0.40
1.69
1.2503
LogMAR BCVA
0.00
Manifest Sphere
-8.25
-0.50
Manifest Cylinder
-2.00
MRSE
-8.500
-1.00

4. Preoperative statistical analysis
Table 2: Preoperative topography, pachymetry, and aberrations data.
Minimum
Maximum
Mean
Std. Deviation
Mean K-Reading
40.15
48.40
Pachymetry
500
633
556.01
31.359
Total rms
0.14
0.81
0.3633
Coma
0.02
0.50
0.1909
Trefoil
0.00
0.1478
Sph. aberrations
-0.38
0.67
0.1338

5. Intraoperative findings
Achieved flap thickness and diameter:
Table 3: Achieved flap thickness and diameter.
Minimum
Maximum
Mean
Std. Deviation
Flap Thickness 91
144
116.48
12.215
Flap Diameter
8.7
9.1
8.956
0.1196

6. Intraoperative findings
Pearson simple linear correlation coefficients:
Table 4: Pearson correlation, flap thickness vs mean k-reading.
Flap Thickness
Mean K-Reading
Pearson Correlation 1
0.017
Sig. (2-tailed) .
*0.855 N
116
117
*P=0.855>0.05
No correlation between flap thickness and K-reading

7. Intraoperative findings
Pearson simple linear correlation coefficients:
Table 5: Pearson correlation, flap thickness vs pachymetry.
Flap Thickness
Pachymetry
Pearson Correlation 1
-0.016
Sig. (2-tailed) .
*0.866 N
116
117
*P=0.866>0.05
No correlation between flap thickness and preoperative corneal thickness

8. Intraoperative findings
Pearson simple linear correlation coefficients:
Table 6: Pearson correlation, flap diameter vs mean k-reading.
Flap Diameter
Mean K-Reading
Pearson Correlation 1
-0.048
Sig. (2-tailed) .
*0.610 N
116
117
*P=0.610>0.05
No correlation between flap diameter and K-reading

9. Intraoperative complications
7.8% intraoperative complication rate.

10. Early postoperative findings
114 eyes, out of 117, were available for postoperative follow-up.
At the first postoperative day, the mean LogMAR UCVA was 0.03 ± 0.11 (mean around 20/22).
At the first postoperative day, the peripheral host epithelium defects were noticed in 2 eyes (1.7%) and fine microstriae in one eye (0.9%).
None of the eyes developed interface inflammation or diffuse lamellar keratitis (DLK).
None of the eyes developed remarkable transient light sensitivity syndrome (TLSS).

11. Late visual and refractive outcomes safety Safety index (postop to preop BCVA) at 1,3, and 6 months = 1.1.
Changes in BCVA in terms of Snellen’s lines.
Table 7: Changes (gain or loss) in Snellen’s lines of BCVA.
1 Month
3 Months
6 Months
2 lines gain 0% 1%
1 line gain
36%
44%
52.1%
Unchanged
62%
53%
44.8%
1 line loss 2%
2.1%
2 lines loss

12. Late visual and refractive outcomes (Efficacy) Efficacy index (postop UCVA to preop BCVA) at 1,3, and 6 months = 1.0.
Time course of logMAR UCVA at 1,3, and 6 months.

13. Late visual and refractive outcomes Efficacy- Total rms
# Sig. increase at 1 m.
# Non-sig. increase at 3 m.
# Back to the 1 m level at 6 m.
Table 10: Total rms at 1, 3, and 6 months.
Minimum
Maximum
Mean
Std. Deviation
Preop. rms
0.14
0.81
0.3633
1 Month rms
0.12
0.90
0.5432
3 Months rms
0.15
0.94
0.5804
6 Months rms
0.86
0.5400

14. Late visual and refractive outcomes Predictability- Attempted vs achieved correction at 6 m

15. Late visual and refractive outcomes Safety
Visante OCT high resolution corneal scan obtained at 6 months postop.

16. Conclusions
In this study, IntraLase was proved to be a safe, efficient, and a highly predictable means of LASIK flap creation.
The IntraLase femtosecond laser has significantly reduced the incidence of LASIK flap complications. In addition to that reduction, IntraLase flap complications are much easier to manage than those of the mechanical microkeratome. Accordingly, IntraLase is becoming recognized as a safer method of flap creation.
Its excellent efficacy and predictability with more predictable flap parameters make the IntraLase a very helpful tool in refractive surgery.

17. THANK YOU