Comparison of flap adhesion strength using the Amadeus microkeratome and the IntraLase iFS femtosecond laser in rabbits.

PURPOSE To compare adhesion strength of flaps created with a mechanical microkeratome and the IntraLase femtosecond laser as well as to analyze the effect of different side-cut configurations. METHODS A flap was created in four groups of New Zealand white rabbits--microkeratome group (Amadeus II microkeratome, Ziemer Group AG [5 eyes; 9-mm suction ring and 140-microm head]), and three IntraLase groups (IntraLase iFS 150 kHz femtosecond laser, AMO Inc [9-mm diameter and 120-microm flap each]): normal energy side-cut (4 eyes; side-cut angle 70 degrees, side-cut energy 0.8 microJ); high energy side-cut (4 eyes; side-cut angle 70 degrees, side-cut energy 1.6 microJ); and inverted side-cut (4 eyes; side-cut angle 140 degrees, side-cut energy 0.8 microJ). Flap adhesion strength was measured 75 days after surgery using a tension meter to dehisce the flaps. RESULTS In the microkeratome group, mean force was 210+/-89 g (range: 151 to 360 g); 492+/-46 g (range: 439 to 540 g) in the normal energy side-cut group; 444+/-13 g (range: 426 to 455 g) in the high energy side-cut group; and 687+/-105 g (range: 552 to 797 g) in the inverted side-cut group. Differences between the microkeratome and all IntraLase groups were highly significant (P=.001), and differences between the inverted side-cut group and the standard 70 degrees side-cut groups were statistically significant (P=.01). CONCLUSIONS Flap adhesion is significantly stronger with the IntraLase femtosecond laser than with the Amadeus mechanical microkeratome, and an inverted side-cut increases flap adhesion significantly compared with a standard side-cut.