Transcript Overview of our Clinical Experience

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
• 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.
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
0.31339
LogMAR BCVA
0.00
0.00
0.00
0.00
Manifest Sphere
-8.25
-0.50
-3.9509
1.79206
Manifest Cylinder
-2.00
0.00
-0.4081
0.45675
MRSE
-8.500
-1.00
-4.15278
1.806218
Preoperative statistical analysis
Table 2: Preoperative topography, pachymetry, and aberrations data.
Minimum
Maximum
Mean
Std. Deviation
Mean K-Reading
40.15
48.40
43.9718
1.61819
Pachymetry
500
633
556.01
31.359
Total rms
0.14
0.81
0.3633
0.13198
Coma
0.02
0.50
0.1909
0.11748
Trefoil
0.00
0.50
0.1478
0.08391
Sph. aberrations
-0.38
0.67
0.1338
0.16629
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
Intraoperative findings
• Pearson simple linear correlation coefficients:
Table 4: Pearson correlation, flap thickness vs mean k-reading.
Flap Thickness
Mean K-Reading
Flap Thickness
Mean K-Reading
Pearson Correlation
1
0.017
Sig. (2-tailed)
.
*0.855
N
116
116
Pearson Correlation
0.017
1
Sig. (2-tailed)
*0.855
.
N
116
117
*P=0.855>0.05
No correlation between flap thickness and K-reading
Intraoperative findings
• Pearson simple linear correlation coefficients:
Table 5: Pearson correlation, flap thickness vs pachymetry.
Flap Thickness
Pachymetry
Flap Thickness
Pachymetry
Pearson Correlation
1
-0.016
Sig. (2-tailed)
.
*0.866
N
116
116
Pearson Correlation
-0.016
1
Sig. (2-tailed)
*0.866
.
N
116
117
*P=0.866>0.05
No correlation between flap thickness and preoperative corneal thickness
Intraoperative findings
• Pearson simple linear correlation coefficients:
Table 6: Pearson correlation, flap diameter vs mean k-reading.
Flap Diameter
Mean K-Reading
Flap Diameter
Mean K-Reading
Pearson Correlation
1
-0.048
Sig. (2-tailed)
.
*0.610
N
116
116
Pearson Correlation
-0.048
1
Sig. (2-tailed)
*0.610
.
N
116
117
*P=0.610>0.05
No correlation between flap diameter and K-reading
Intraoperative complications
7.8% intraoperative complication rate.
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).
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%
1 line gain
36%
44%
52.1%
Unchanged
62%
53%
44.8%
1 line loss
2%
2%
2.1%
2 lines loss
0%
0%
0%
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.
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
0.13198
1 Month rms
0.12
0.90
0.5432
0.20781
3 Months rms
0.15
0.94
0.5804
0.22879
6 Months rms
0.14
0.86
0.5400
0.20185
Late visual and refractive outcomes
Predictability- Attempted vs
achieved correction at 6 m
Late visual and refractive outcomes
Safety
•
Visante OCT high resolution corneal scan obtained at 6 months postop.
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.
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