LASIK Flap Thickness and Visual Outcomes Using the WaveLight FS200 Femtosecond Laser

Laser in situ keratomileusis (LASIK) is a method for treating myopia, hyperopia and astigmatism. In LASIK, the cornea is reshaped to focus images more clearly on the retina without the aid of glasses or contact lenses. LASIK involves two steps: creation of a corneal flap, which can be performed by a mechanical microkeratome or a femtosecond laser, and reshaping of the cornea by another laser, an excimer laser.

The accuracy of the LASIK flap thickness is a key safety consideration to reduce the likelihood of complications following LASIK. Femtosecond laser technology has significantly improved the predictability of LASIK flap dimensions while supporting similar visual acuity results.

The Alcon FS200 femtosecond laser is approved for human use by the United States Food and Drug Administration and was recently released in the US market. This study will directly compare outcomes of LASIK performed with this newer laser to those performed with the AMO IntraLase femtosecond laser.

Inclusion criteria

• All patients with ametropia (Spherical, spherocylindrical, presbyopic) suitable for treatment by LASIK, including different target refractions (Plano or Monovision).

Exclusion criteria

• Patients unsuitable for LASIK procedure because of an estimated residual stromal bed < 300 microns after calculation of the ablation (Corneal thickness - flap thickness - simulated stromal ablation for the desired correction).
• Patients unsuitable for LASIK due suspicious topography for ectasia, form frust keratoconus or unstable ( more than 0.50 diopter change in sphere or cylinder in the last year) refraction.
• Patients with amblyopia or any eye disease that might limit the visual recovery.
• Patients younger than 18 years old.