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| Femtosecond
Laser versus Mechanical Microkeratome for LASIK: A Randomized Controlled
Study |
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Presented at: Association
for Research in Vision and Ophthalmology Annual Meeting, May 2006,
Fort Lauderdale, Florida.
Sanjay V. Patel, Leo J. Maguire, Jay W. McLaren, David O. Hodge,
William M. Bourne |
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| Purpose |
| To compare corneal haze (backscattered light) and visual outcomes between fellow eyes randomized to LASIK with the flap created by a femtosecond laser (bladeless) or with the flap created by a mechanical microkeratome. |
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| Design |
| Randomized, controlled, paired-eye
study.
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| Participants |
| Twenty-one patients (42 eyes)
received LASIK for myopia or myopic astigmatism.
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| Methods |
| One eye of each patient was
randomized to flap creation with a femtosecond laser (IntraLase
FS, IntraLase Corp., Irvine, CA) with intended thickness of 120
µm, and the fellow eye to flap creation with a mechanical
microkeratome (Hansatome, Bausch & Lomb, Rochester, NY) with
intended thickness of 180 µm. Patients were examined before
and at 1, 3, and 6 months after LASIK.
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| Main Outcome Measures |
| Corneal backscatter, high-contrast
visual acuity, manifest refractive error, contrast sensitivity,
and intraocular forward light scatter were measured at each examination.
Flap thickness was measured by confocal microscopy at 1 month, and
patients were asked if they preferred the vision in either eye at
3 months.
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| Results |
| Corneal backscatter was 6%
higher after bladeless LASIK than after LASIK with the mechanical
microkeratome at 1 month (P = 0.007), but not at 3 or 6 months.
High-contrast visual acuity, contrast sensitivity, and forward light
scatter did not differ between treatments at any examination. Flap
thicknesses at 1 month were 143±16 µm (bladeless, mean
± standard deviation) and 138±22 µm (mechanical
microkeratome), with no statistical difference in variances. At
3 months, 5 patients preferred the bladeless eye, 7 patients preferred
the microkeratome eye, and 9 patients had no preference.
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| Conclusions |
| The method of flap creation
did not affect visual outcomes during the first 6 months after LASIK.
Although corneal backscatter was greater early after bladeless LASIK
than LASIK with the mechanical microkeratome, patients did not perceive
a difference in vision.
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