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Lasik

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What is LASIK?

Laser-assisted in situ keratomileusis, more commonly referred to as LASIK, is a two-phase procedure that gently reshapes the cornea of the eye, allowing light to properly focus on the retina. By reshaping the cornea, we are often able to decrease or completely eliminate the need for glasses and contact lenses. LASIK is an outpatient procedure with very little recovery time associated with it.

Both nearsighted and farsighted people can benefit from the LASIK procedure. With nearsighted people, the goal is to flatten the too-steep cornea; with farsighted people,
a steeper cornea is desired. While this is not widely recognized by consumers, Excimer lasers also can correct astigmatism by smoothing an irregular cornea into a more normal shape.

Variations of the procedure include Epi-LASIK, PRK, and custom Wavefront LASIK, in which wavefront technology is used to map the surface of the eye, creating a custom ablation.

Some people are confused about the purpose of LASIK. It is intended to improve your ability to see clearly, reducing your dependence on eyeglasses and contact lenses. It is not a treatment for glaucoma, cataracts, macular degeneration, diabetic retinopathy or other eye diseases.

The LASIK Procedure
During the first phase of the LASIK procedure, a thin flap of corneal tissue is created on the surface of the eye. During the second phase of the LASIK procedure, the corneal flap is lifted and a cool laser beam of light is used to gently reshape the cornea, which in turn corrects your vision.

The desired shape of the cornea is determined by extensive testing and measurements that are calculated for your particular eyes. Corneal thickness, topography, corneal shape, refractive stability and severity and general eye health are just a few of the factors that enter into this decision.

The LASIK vision correction procedure will typically take between five and fifteen minutes for both of your eyes. Most LASIK eye surgery patients notice a dramatic improvement in their vision immediately after the LASIK procedure.

PRK (Photo Refractive Keratectomy)
PRK was the first procedure performed using the Excimer laser. It corrects vision by reshaping the cornea. The difference between LASIK and PRK is that with LASIK a corneal flap is created and the laser is applied to the inner tissue of the cornea. With PRK, the epithelium (or outer skin of the cornea) is removed and a laser is applied to the surface of the cornea.
PRK can be used to correct low to high levels of nearsightedness, farsightedness and astigmatism. PRK is preferred for patients with thin corneas.

PRK vs. LASIK. Because PRK does not create a permanent flap in the deeper corneal layers (the LASIK procedure involves a mechanical microkeratome using a metal blade or a femtosecond laser microkeratome to create a 'flap' out of the outer cornea), the cornea's structural integrity is less altered by PRK.

The LASIK process covers the laser treated area with the flap of tissue which is from 100 to 180 micrometres thick. This flap can mute the nuances of the laser ablation, whereas PRK performs the laser ablation at the outer surface of the cornea. The use of the anti-metabolite mitomycin can minimize the risk of post-operative haze in persons requiring larger PRK corrections.
PRK does not involve a knife, microkeratome, or cutting laser as used in LASIK, but there may be more pain and slower visual recovery.


 

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