Bladeless LASIK and Why the Flap Matters

Two ways to make a flap

LASIK begins by creating a thin hinged flap in the cornea so the laser can reshape the tissue beneath it. In the early years of LASIK that flap was cut with a microkeratome, an oscillating steel blade that travels across the cornea. Microkeratome flaps work, but their thickness varies from eye to eye and even across a single flap, and the mechanical pass carries small risks of an incomplete or irregular flap.

A femtosecond laser makes the flap differently. It fires ultrashort pulses of infrared light that are focused at an exact depth inside the cornea, where each pulse creates a microscopic bubble. Millions of bubbles placed side by side separate the tissue along a plane, creating a flap of precisely the thickness and diameter the surgeon programmed. The eye is not cut; it is separated at a chosen depth.

What a laser flap changes for the patient

The practical differences are in predictability and in what is left behind:

• A thinner, more uniform flap leaves more corneal tissue beneath it, which widens the range of prescriptions that can be treated safely and preserves long term corneal strength
• The flap edge can be angled so it locks back into position, which reduces the chance of the flap moving in the first days
• The risk of a partial, buttonhole or free flap, the classic microkeratome complications, is greatly reduced
• Patients with corneas that would have been too thin for a blade flap can often have LASIK rather than PRK

Bladeless, all-laser and femto-LASIK: the same thing

You will see this procedure called bladeless LASIK, all-laser LASIK, femto-LASIK or laser-flap LASIK. They all describe LASIK in which the flap is made by a femtosecond laser and the reshaping is done by an excimer laser. The names differ; the procedure does not.

Is there still a place for the microkeratome?

Some surgeons still use microkeratomes and achieve good results with them. Many practices have moved to femtosecond flaps because the gain in predictability and safety is well established in the published literature and because a thinner flap can allow more patients to have LASIK who would otherwise need surface treatment. Your surgeon will explain how your flap would be made. If your cornea is not suited to any flap at all, the answer is PRK or SMILE rather than a different blade.