Comparison of Flap Adhesion Strength Using the Amadeus Microkeratome and the IntraLase iFS Femtosecond Laser in Rabbits

Abstract

<h4>PURPOSE</h4><p>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.</p> <h4>METHODS</h4><p>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-µm head]), and three IntraLase groups (IntraLase iFS 150 kHz femtosecond laser, AMO Inc [9-mm diameter and 120-µm flap each]): normal energy side-cut (4 eyes; side-cut angle 70°, side-cut energy 0.8 µJ); high energy side-cut (4 eyes; side-cut angle 70°, side-cut energy 1.6 µJ); and inverted side-cut (4 eyes; side-cut angle 140°, side-cut energy 0.8 µJ). Flap adhesion strength was measured 75 days after surgery using a tension meter to dehisce the flaps.</p> <h4>RESULTS</h4><p>In the microkeratome group, mean force was 210±89 <i>g</i> (range: 151 to 360 <i>g</i>); 492±46 <i>g</i> (range: 439 to 540 <i>g</i>) in the normal energy side-cut group; 444±13 <i>g</i> (range: 426 to 455 <i>g</i>) in the high energy side-cut group; and 687±105 <i>g</i> (range: 552 to 797 <i>g</i>) in the inverted side-cut group. Differences between the microkeratome and all IntraLase groups were highly significant (<i>P</i>=.001), and differences between the inverted side-cut group and the standard 70° side-cut groups were statistically significant (<i>P</i>=.01).</p> <h4>CONCLUSIONS</h4><p>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. [<cite>J Refract Surg.</cite> 2008;24:875-878.]</p> <h4>AUTHORS</h4> <p>From FreeVis LASIK Zentrum (Knorz) and the Department of Ophthalmology (Vossmerbaeumer), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany.</p> <p>Dr Knorz is a consultant to AMO, Irvine, Calif. Dr Vossmerbaeumer has no proprietary interest in the materials presented herein.</p> <p>This study was supported by an unrestricted educational grant from AMO Inc, Irvine, Calif.</p> <p>The authors thank Drs Melvin Sarayba and Tes Ignacio for their support during the rabbit surgery.</p> <p>Correspondence: Michael C. Knorz, MD, FreeVis LASIK Zentrum, Theodor Kutzer Ufer 1-3, 68167 Mannheim, Germany. Tel: 49 160 53 88 080; Fax:49 621 383 1984; E-mail: <a href="mailto:knorz@eyes.de">knorz@eyes.de</a></p> <p>Received: February 26, 2008</p> <p>Accepted: July 8, 2008</p> <p><b>Posted online: August 29, 2008</b></p>

Interface quality of different corneal lamellar–cut depths for femtosecond laser–assisted lamellar anterior keratoplasty

“…In LASIK, the inverted side cut improves the strength of the healed wound. 36 The recipient side-cut angle was shallower than the donor. This minimizes the host side-cut depth to lessen the weakening of the host cornea.…”

When case report became case series: 45 cases of late traumatic flap complications after laser-assisted in situ keratomileusis and review of Chinese literature

“…Some studies showed that flap adhesion created with the femtosecond laser were stronger, and more uniform, regular and accurate than with the mechanical microkeratome 19 20. But there have also been reports of late traumatic flap complications, in the literature published in both English and Chinese 21 22.…”

Femtosecond laser in laser in situ keratomileusis

“…It follows that there is less likelihood of producing flaps that threaten the biomechanical stability of the cornea or disrupt the epithelium when the femtosecond laser is used for LASIK. 27,56,57 Knorz and Vossmerbaeumer 58 evaluated and compared the adhesion strength of flaps created with a mechanical microkeratome and a femtosecond laser. They found that flap adhesion was stronger with a femtosecond laser flap.…”

“…As discussed, femtosecond flaps have stronger adhesion than microkeratome flaps, 58 which may provide additional protection from the lower eyelid and inadvertent manipulations by the patient during the early postoperative period. When flap striae occur after LASIK performed with the femtosecond laser, management is similar to that with LASIK performed with the microkeratome.…”