How Lasik works

LASIK is a refractive surgical procedure to help correct vision problems.The term LASIK is an abbreviation or acronym for laser-assisted in-situ keratomileusis, which means "to reshape the cornea, from within, using a laser." In LASIK, the corneal surface is treated underneath a protective corneal flap. It is one of several corrective procedures for the treatment of familiar vision problems that you may already have heard of, including nearsightedness, farsightedness and/or astigmatism.

While glasses and contact lenses also help correct problems such as these, they are considered vision aids, not surgical procedures. These types of procedures are, in fact, designed to help people eliminate, or reduce the need for glasses or contact lenses. LASIK is not the appropriate procedure for everyone and it is important to know if it is right for you. The ERC with your physician can help you determine this.

You may experience nearsightedness, farsightedness and/or astigmatism because your cornea is inadequately shaped for the dimensions of your eye. In use since the late 1980s, LASIK utilizes a laser beam to remove small amounts of tissue from the cornea to reshape it and correct the refractive error. The reshaped cornea then focuses images directly on the retina. For many patients, a successful LASIK procedure can mean clearer vision with the potential to eliminate glasses or contact lenses.

Before the day of your LASIK procedure, your doctor and the medical staff of the ERC let you know what to expect and how to prepare for it. The following animation will show you how LASIK works to correct different vision problems.

Customized Laser Vision Correction

There's a new LASIK procedure called CustomCornea® that promises to deliver truly customized vision correction. This exciting new procedure can treat all of the conditions LASIK surgery is traditionally used to correct, as well as a range of vision problems that could not be detected before. Experts believe these problems, called higher order aberrations, are responsible for many low-light vision problems, including glare and halos. In October 2002, CustomCornea® became the first FDA-approved laser vision correction procedure capable of measuring and treating higher order aberrations.

Vision Problems LASIK Cannot Correct

One common vision problem, presbyopia, cannot be corrected by any laser vision correction surgery. This condition is the result of an inelastic lens, not a misshaped cornea, and is part of the natural aging process for many people. If you have presbyopia and require reading glasses, laser vision correction surgery will not correct the problem. Although results vary from patient to patient, if you currently wear contact lenses to correct nearsightedness or farsightedness along with reading glasses for presbyopia, laser vision correction may eliminate or reduce the need for the contact lenses, but not for the reading glasses.

LASEK

If the cornea is too thin LASEK can be the right choice with this technique it's possible to make avery thin flap. We are using alcohol to seperate the Edithelium once the ablatish is finished we put the Epithelium back (see drawing).

Low-light vision problems

In addition to those vision problems you've probably heard of before — the lower order aberrations like nearsightedness and farsightedness — there are common vision problems known as higher order aberrations that can also affect your vision. Higher order aberrations are widely believed by ophthalmic experts to contribute to common night vision problems, including glare and halos.

Higher order aberrations cannot be corrected through traditional LASIK procedures. Similarly, glasses and contact lenses are unable to help with these vision problems. An exciting new procedure, called CustomCornea®, is capable of correcting both lower order and higher order aberrations.

Diagnosing higher order aberrations

Higher order aberrations are diagnosed and measured using wavefront maps. These maps are plotted by passing a narrow ray of eye-safe light through the optical system and measuring the optical distortions as the light exits the eye. These patterns are then compared with the flat wavefront associated with normal vision. An ideal wavefront map would be perfectly flat.