Femtosecond laser-assisted lens surgery depending on interface design and laser pulse energy. Results of the first 200 cases

This study was designed to evaluate the effectiveness and safety of femtosecond laser-assisted lens surgery depending on interface design and laser pulse energy settings. In this non-randomized, consecutive case series200 eyes underwent femtosecond laser-assisted (LenSx, Alcon) lens surgery between November 2012 and June 2013. Group 1 consisted of 85 eyes with 60 cataracts and 25 refractive lens exchanges (RLE) which were treated with a curved direct contact interface, and group 2 consisting of 115 eyes with 72 cataracts and 43 RLEs treated with a modified interface using an additional soft contact lens (SoftFit (TM), Alcon) between the corneal surface and the interface. The degree of opacity of the lens in cataract eyes was measured with a Scheimpflug camera. Afterwards, phacoemulsification was performed with intraocular lens (IOL) implantation in all eyes. Primary endpoints were the effective phacoemulsification time (EPT), the average laser treatment time and the occurrence of intraoperative complications. The mean EPT in group 1 was 1.62 +/- 1.12 s (cataract 1.94 +/- 1.31 s, RLE 1.29 +/- 1.01 s) and in group 2 the mean EPT was 1.66 +/- 0.92 s (cataract 1.98 +/- 1.28 s, RLE 1.33 +/- 1.22 s, p = 0.32 between groups). The laser treatment lasted on average 48.90 +/- 2.45 s (group 1) and 49.70 +/- 2.87 s (group 2) with an average lens fragmentation thickness of 3401.48 +/- 401.12 A mu m (all groups). In four cases of group 1, a second applanation of the interface was necessary. Furthermore, one anterior capsule tear, 39 cases of intraoperative wrinkling of the corneal surface and 21 cases in which the corneal incision had to be opened manually were documented in group 1. In group 2 no second applanation of the interface, no anterior capsule tears and no corneal wrinkling but 9 cases with a manual opening of corneal incisions were documented (p < 0.01 between groups). The minor intraoperative complications of the femtosecond laser technique investigated could be significantly reduced using an optimized interface and reduced laser pulse energy.