How LASIK Works

LASIK (or laser-assisted in situ keratomilieusis) is the most commonly performed Laser Vision Correction procedure in the world, accounting for more than 90% of all LVC procedures. LASIK works by first creating a flap in the cornea (our practice uses a blade-free femtosecond laser to do this), which is folded out of the way. An excimer laser then corrects your refractive error by removing a microscopic layer of the cornea in a precise pattern customized, whenever possible, to each patient’s eye. The laser will flatten your cornea if you are myopic, steepen it if you are hyperopic, or round it out if you have astigmatism. The flap is then smoothed down over the cornea, aligning back perfectly as in a jigsaw puzzle. The corneal flap sticks back like a “Post-It Note” within a few minutes, and the procedure is over.

 

What makes LASIK so popular is the rapid improvement of vision when compared to other forms of LVC. No matter how strong your prescription, the average LVC patient can usually pass a driver’s vision test twenty-four hours after surgery, often even after only one hour. This quick, often miraculous recovery is due to the use of the blade -free femtosecond laser. The surgeon uses the femtosecond laser on the cornea after using numbing eye drops and, using a suction device to lock the laser into place, creates a corneal flap. This thin flap of corneal tissue is folded out of the way and the excimer laser removes a thin layer of corneal tissue to correct your visionflattening your cornea if you are myopic, steepening your cornea if you are hyperopic, or rounding it out if you are astigmatic. The surgeon then smoothes down the flap, fitting it back exactly where it came from, like a piece in a jigsaw puzzle, over the ablated area. The corneal flap adheres to the rest of the cornea within minutes and the procedure is over.

 

shutterstock_92469055(1)LASIK Manhattan, VISX – In just a short time, patients burdened for years with wearing glasses or contact lenses often achieve vision so clear that the first word out of their mouths is an incredulous, “Wow.”  Why does vision recover so quickly? The answer is that the corneal surface in the line of sight (visual axis) remains practically untouched. When the flap of corneal tissue is created, the U-shaped narrow seam is the only area of the cornea’s surface that is disrupted. The surface and center of the cornea, the part through which you see, is untouched. Within a few hours or overnight, the seam, or “gutter,” fills in with new cells that grow very rapidly across the seam. In the average patient, by the following morning the flap has adhered, the seam has healed, and that clock across the room is no longer the blur it was the day before.

 

The corneal flap also makes it easier to perform enhancements. If you did not achieve the level of vision you wanted, another laser treatment may be performed a few months or even years later. The surgeon carefully breaks the seal on the flap, lifting the flap once again as in the original procedure, and performs an additional laser ablation. Enhancements are usually very successful, but may not be advisable if your original, untreated cornea was thin.

Although the rapidly healing corneal flap is largely responsible for the wow factor, it is also responsible for the majority of complications that can result from LASIK. The flap can be too thin, too thick, too small, irregular, incomplete, or “button-holed.” It can develop wrinkles, folds, and striae-all of which can lead to delayed or poor healing or a poor visual result. Fortunately, flap problems are rare, especially with the femtosecond or Intralase laser, and in most cases can be treated successfully.