Ultra-short, ultra-intense laser pulses from a first laser beam are applied to a patients cornea, creating a temporary micro-channel extending from the cornea surface to an end-point within it. Further ultra-short ultra-intense laser pulses from a second laser beam, are then delivered to the endpoint along with further pulses from the first beam, but delayed by a few nanoseconds. The micro-channel acts as a light-guide for these pulses. At the end point, they are focused to sufficient intensity to multiphoton ablate surrounding stromal tissue. With a few small entrance holes and without the lamellar flap necessary in LASIK procedures, the cornea is reshaped by rotating the direction of the laser beam. The vertical location of ablation is adjusted precisely using an applanator on the corneal surface. The multiphoton ablated tissue is ejected via the micro-channels, allowing the cornea surface to collapse after the procedure, changing its refractive power.
