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What factors determine the range and accuracy of treatment possible? |
There are 3 main factors which affect how much and how accurate the treatment is.
The first factor is the thickness of the patient’s cornea1. The thicker the cornea is, the greater the amount of correction that can be achieved. Usually the remaining corneal bed must be at least 200 to 250 microns thick.
The second factor is the size of the patient’s pupil in the dark. Larger pupils require deeper and wider treatments.
The flap does not contribute to the strength of the cornea. Most experienced LASIK surgeons try to make the flap as thin as possible. However if a flap is made too thin, it can buttonhole and the LASIK procedure has to be aborted. A thin flap maximizes the remaining cornea bed available for treatment.
Finally, the higher the power, the less accurate the correction. This is because more correction requires a larger amount of tissue to be ablated and a longer time of treatment.
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