Contrast Sensitivity After LASIK Flap Creation With a Femtosecond Laser and a Mechanical Microkeratome

Abstract

PURPOSE: To compare the effects on contrast sensitivity of the IntraLase femtosecond laser for flap creation (IntraLASIK) and standard LASIK for myopia. METHODS: Two hundred eyes of 100 consecutive patients underwent LASIK treatment using the VISX S2 laser system. The femtosecond laser (15 kHz IntraLase) was used for flap creation in 100 eyes (50 patients) and a mechanical microkeratome (Carriazo-Barraquer) was used in 100 eyes (50 patients). Best spectacle-corrected contrast sensitivity was measured before and 6 months postoperatively in the IntraLASIK and mechanical LASIK groups. The IntraLASIK and mechanical LASIKinduced changes in contrast sensitivity were compared under photopic (85 cd/m2) and mesopic (5, 2.5, and 0.1 cd/m2) conditions. RESULTS: Contrast sensitivity for eyes after IntraLASIK did not differ from preoperative values at the photopic level (85 cd/m2). However, under mesopic conditions, a statistically significant reduction (P<.01) in contrast sensitivity was found at high spatial frequencies (12 and 18 cpd), although no significant contrast sensitivity differences were observed at low and middle spatial frequencies (P>.01 for 1.5, 3, and 6 cpd). No statistically significant differences were found between IntraLASIK and mechanical LASIK for 1.5,3, and 6 cpd at any luminance level (P>.01). IntraLASIK showed better contrast sensitivity than mechanical LASIK under mesopic conditions at 12 cpd and photopic and mesopic conditions at 18 cpd (P<.01). CONCLUSIONS: IntraLASIK surgery demonstrated better contrast sensitivity at high spatial frequencies under photopic and mesopic conditions than mechanical LASIK. [J Refract Surg. 2007;23:188-192.]

Comparative micromorphologic in vitro porcine study of IntraLase and Femto LDV femtosecond lasers

“…Most have shown that the femtosecond laser provides more predictable flap thickness than mechanical microkeratomes. 17,18 …”

IntraLase Femtosecond Laser vs Mechanical Microkeratomes in LASIK for Myopia: A Systematic Review and Meta-analysis

“…Of 15 selected studies published between 2004 and 2010, 5 reported random selection for the use of IntraLase in 1 eye and microkeratome in the other eye for each patient, 7,8,34,40,42 and 5 reported the data with a followup of у12 months. 8,33,[39][40][41] When two or more types of microkeratomes were used in 1 article, we combined them into a single group according to the Cochrane Collaboration guidelines. 15 The characteristics and quality of the included trials are summarized in the Table and Appendix 2 (available online at www.…”

Incidence, possible risk factors, and potential effects of an opaque bubble layer created by a femtosecond laser

“…These studies showed significantly better predictability of the manifest spherical equivalent (SE) at the approximately 0.50 diopter (D) level and a reduction in the overall induced astigmatism in spherical treatments with the laser keratomes. 3,7 Although some studies report that laser keratomes resulted in better contrast sensitivity at high spatial frequencies, 8 others found no difference between laser keratomes and mechanical keratomes in final visual acuity and contrast sensitivity. 9,10 Certain side effects are unique to the femtosecond laser.…”