The best candidates for the PRK have an eyeglass prescription that isn't extreme. This means that, if you are nearsighted, you may have a myopia of up to —8, 00 diopters. If you have farsightedness, your farsightedness can be up to +3, 00 diopters. Your astigmatism level can be as high as +4, 00 diopters.
In most clinics, the prescription limit for treating hyperopia with LAIK is usually between 3.0 and 4.0 D. Currently, most clinics cannot treat patients with severe hyperopia (5.0 D +) because they do not have access to the latest technology to do so safely. How is your vision? People with a high corrective prescription (-8.00 or -9.00, for example) are usually better suited for PRK. This is because, Hood points out, the element of LASIK that forms pendants requires the recipient to have enough residual cornea to be structurally healthy after remodeling a deficit that is seen in patients with vision problems and also in those with very thin corneas.
Patients with a higher corrective prescription (for example, -8.00 or -9.00) may be better suited for PRK if they do not have enough corneal tissue for both flap vision correction treatment and laser vision correction treatment. Because recovery time is longer in PRK, it is important that patients are not exposed to intense sun for at least one to two months. Once again, the possible corneal flap as a result of LASIK represents a risk for competitive athletes or patients who are more likely to suffer an eye injury, so they should consider PRK. During the evaluation process, your doctor may ask you some of the following questions to determine if you should undergo LASIK, PRK, or another procedure (such as LASEK or Epi-LASIK).
Because of the removal of the corneal surface, PRK takes a little longer (and, unlike LASIK, there is slight pain). Patients can see clearly a few hours after LASIK, but because of the removal of the corneal surface in PRK, it takes a little longer. I recently performed ICL surgery followed three months later by PRK on a patient from Turkey who had a prescription of -23.00 diopters.