Resumen de Femtosecond Laser Compared with a Mechanical Keratome for LASIK in Myopes

Caroline Baily, Gráinne Brosnan, Michael O'Keef

• BACKGROUND: To compare clinical outcomes between fellow eyes randomised to femtosecond laser-created flaps or mechanical keratome-created flaps during laser in-situ keratomileusis in myopes.

  DESIGN: Prospective, randomised clinical study.

  PARTICIPANTS: 31 patients (62 eyes) were included in this study.

  METHODS: Eyes were randomised to either the femtosecond or mechanical keratome group. For analysis of higher order aberrations (HOA) patients were divided into those who had wavefront-guided and aspheric treatment (group 1) and those who had tissue-saving treatment (group 2).

  MAIN OUTCOME MEASURES: Flap thickness, visual outcome (efficacy, safety, and predictability), tear analysis, HOA, corneal hysteresis and contrast sensitivity were compared at three months postoperatively.

  RESULTS: The average flap thickness (mean±standard deviation [SD]), on optical coherence tomography measurement at three months postoperatively was 117.17±15.62 µm (intended flap thickness 110 µm) in the femtosecond group and 148.39±16.13 µm (intended flap thickness 120 µm) in the mechanical keratome group, p=0.000. The mean±SD preoperative total HOA root mean square in the femtosecond group (group 1) was 0.419±0.190 µm which increased significantly to 0.773±0.356 µm at three months postoperatively (p=0.005, [Table 1]). There was no significant increase postoperatively in the mechanical keratome group ([group 1] p=0.075). There was no significant increase in preto postoperative differences between the femtosecond and mechanical keratome groups (p=0.071). There was no difference in visual outcome, tear analysis, corneal hysteresis or contrast sensitivity between the femtosecond and mechanical keratome groups at three months postoperatively.

  CONCLUSION: The femtosecond laser creates a thinner more predictable flap.