Each corneal refractive procedure can treat a certain range of refractive errors. This page outlines the limits of treatment that can be achieved. The clinical circumstances of each eye (corneal thickness, flap thickness, optical zone, prior procedures, ocular comorbidities, etc.) must be considered. In the case of LASIK and PRK, some tissue needs to be held in reserve in the event an enhancement is necessary. One of Our Doctors can tell you if your eyes fit within the boundaries of a particular treatment. Phakic intraocular lens implantation and natural lens exchange, which are intraocular procedures, may be possible if you fall outside the range of the treatments listed below.
LASIK
Our Alcon WaveLight® EX500 laser system is approved for the following wavefront optimized treatments:
Myopia with or without astigmatism: Up to -12.0 D of myopia with or without astigmatism of up to 6.0 D, in patients who are 18 years of age or older with documented evidence that their refraction did not change by more than 0.5 D during the year before the preoperative examination.
Hyperopia with or without astigmatism: Up to + 6.0 diopters of hyperopia with or without astigmatism of up to 5.0 D, with a maximum manifest refraction spherical equivalent of + 6.0 diopters, in patients who are 18 years of age or older and have documented evidence that their refraction did not change by more than 0.5 D during the year before the preoperative examination.
Mixed astigmatism: Up to 6.0 D of mixed astigmatism, in patients who are 21 years of age or older and have documented evidence that their refraction did not change by more than 0.5 diopter during the year before the preoperative examination.
PRK
The same Alcon WaveLight® EX500 laser system that we use for LASIK is also used for PRK, so the same limits on treatment apply. PRK may be a good alternative to LASIK if your corneas are thin and you need a high correction.
PCRI/AK
The maximum amount of astigmatism that can be corrected by PCRI/AK is 3.0 D. Results become increasingly unpredictable beyond 1.5 to 1.75 D. PCRI does not change the spherical equivalent power of the eye, so the procedure is indicated only when the spherical equivalent power of the eye is already within 0.5 D of intended.
SMILE
Our Zeiss VisuMax® laser system is approved for the following treatment:
Myopia with or without astigmatism: Up to – 10.0 D of myopia with or without astigmatism of up to 3.0 D, in patients who are 22 years of age or older and who have documented evidence that their refraction did not change by more than 0.5 D during the year before the preoperative examination.
