Instead of making a cut in the outer layer of the cornea, the iFS femtosecond laser emits tiny pulses of laser light to create a uniform layer of microscopic bubbles beneath the surface of the eye. These bubbles indirectly separate the tissue so the surgeon can gently lift back the flap in preparation for the excimer laser correction. After the excimer laser correction, the flap is restored to its original position and “locks” back into place.