Purpose: To compare the increase in intraocular pressure (IOP) during corneal flap preparation in porcine eyes when using a femtosecond laser or a mechanical microkeratome.
Setting: The present study was conducted at a university hospital and a private clinic.
Methods: The vitreous IOP was directly measured with a cannula through the optic nerve in 24 porcine globes (n = 12 for each device). In the first procedure (worst-case procedure), the eye interface was lowered against the globe until abortion of the docking maneuver when using the IntraLase femtosecond laser (Abbott Medical Optics, Santa Ana, CA) or the suction ring was pressed very firmly against the globe when using the Amadeus microkeratome (Ziemer Ophthalmic Systems AG, Port, Switzerland). In the second procedure (regular procedure), a normal lamellar flap creation was performed using each of these devices.
Results: During the worst-case procedure, a maximum IOP of 260 ± 53 mm Hg (mean ± SD) was reached with the IntraLase and 318 ± 59 mm Hg was reached with the Amadeus. During the regular procedure, the maximum IOP increased to 135 ± 16 mm Hg when using the IntraLase femtosecond laser and to 152 ± 24 mm Hg with the Amadeus microkeratome.
Conclusions: In the worst-case procedure, the maximum IOP levels were lower in the IntraLase group. No significant difference in maximum IOP levels could be obtained during the regular procedure. The duration of the suction phase is longer when using the IntraLase femtosecond laser.