Astigmatism and its Importance in Lasik Eye Surgery

It is an eye surgery that permanently changes the shape of the cornea (the transparent covering at the front of the eye). This is done to improve vision and reduce the need for the person to wear glasses or contact lenses.


For clear vision, the cornea and lens of the eye must properly angle (refract) light rays. This allows the images to focus on the retina. Otherwise, the images will be blurry.

This blurring is called “refractive error.” This error is caused by a difference between the shape of the cornea (curvature) and the length of the eye.

LASIK happens to use an excimer laser (an ultraviolet laser) for removing a thin layer of corneal tissue. This gives the cornea a new shape so that light rays are clearly focused on the retina. LASIK makes the cornea thinner.

LASIK surgery is an outpatient surgical procedure. It takes ten to fifteen minutes for each eye.

The only anesthetic used ay the is an eye drop that numbs the surface of the eye. The procedure is done while you are awake, but you will be given medicine to help you relax. LASIK Eye Surgerycan be done on one or both eyes in the same session. To perform the procedure, a corneal tissue flap is created. This flap is then detached so that the excimer laser can reshape the underlying corneal tissue. A hinge in the flap prevents the flap from completely separating from the cornea.

The first time LASIK surgery was performed, a special automated knife (a microkeratome) was used to cut the flap. Now a more common and safer method is to use a different type of laser (femtosecond) to create the corneal flap.

The amount of tissue to be removed with the laser is calculated in advance. The surgeon will calculate this amount based on several factors including:

  • Your prescription glasses or contact lenses.
  • A wavefront test, which measures how light travels through your eye
  • The shape of the corneal surface

Once the reshaping is done, the surgeon replaces the flap and secures it. No sutures are needed. The cornea will certainly hold the flap in place.