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To measure intraocular pressure (IOP) elevations in porcine eyes during laser in situ keratomileusis (LASIK) performed using 3 femtosecond laser platforms. Clínica Novovisión, Madrid, Spain. Experimental study. Three femtosecond devices, the iFS 150 kHz, which is the newest-generation IntraLase with a flat interface, and the Victus and LenSx, which are both dual femtosecond lasers with curved interfaces, were used to create lamellar corneal flaps in freshly enucleated porcine eyes. The IOP was recorded during placement of the suction ring on the eye (suctioning phase) and during the intrastromal laser application for flap creation (cutting phase) using a manometric technique with direct cannulation to the anterior chamber. Twenty-one eyes were analyzed (7 per group). The mean IOP increase during suctioning was significantly higher with the iFS system (78.14 mm Hg ± 23.6 [SD]) than with the Victus system (20.28 ± 6.7 mm Hg) (P =.0001). The LenSx system performed the suctioning and applanation phases simultaneously, making it impossible to obtain the results of the suctioning phase alone. The mean IOP elevation during the cutting phase was significantly lower with the LenSx system (20 ± 5.3 mm Hg) than with the iFS (108.1 ± 17.0 mm Hg) and Victus (96.4 ± 16.8 mm Hg) systems (P =.0001). The total surgical time was significantly lower with the LenSx system (17.21 ± 0.7 seconds) than with the iFS (25.10 ± 4.3 seconds) and Victus (33.40 ± 0.7 seconds) systems (P =.0001). The preliminary results suggest that the iFS and Victus systems induced higher IOP increases and required longer surgical times to cut a LASIK flap than the LenSx system. [ABSTRACT FROM AUTHOR]

To analyze the recovery of the subbasal nerve plexus in corneas treated with laser in situ keratomileusis (LASIK) at least 10 years prior compared with nonoperated corneas. Clínica Novovisión, Madrid, Spain. Prospective nonrandomized observational study. Eyes that had LASIK surgery at least 10 years before (LASIK group) were compared with nonoperated healthy eyes (control group). The subbasal nerve plexus morphology (main nerves density, nerve length, nerve branches density, grade of nerve tortuosity, and reflectivity) and the dendritic cell density from the confocal images obtained with the Heidelberg Retina Tomograph II were analyzed. The study comprised 47 eyes (27 eyes in the LASIK group and 20 eyes in the control group). The values were significantly lower in the LASIK group compared with the control group in main nerves density (9.15 nerves/mm2 ± 3.46 [SD] versus 11.75 ± 2.86 nerves/mm2; P =.009) and nerve branches density (2.96 ± 1.99 nerves/mm2 versus 5.35 ± 3.05 nerves/mm2; P =.002). No significant differences were found in nerve length, grade of nerve tortuosity, dendritic cell density, or subbasal nerve plexus reflectivity between the two groups. The outcomes suggested that the subbasal corneal nerve plexus did not completely recover its preoperative pattern at least 10 years after LASIK. Both main nerves density and nerve branches density continued to be significantly lower compared with virgin corneas after a mean 13-year follow-up, although other parameters of nerve morphology (nerve length, tortuosity, and reflectivity) returned to normal levels. [ABSTRACT FROM AUTHOR]