You have high myopia if the sphere part of your eyeglass prescription is between -7.00 and -10.00 diopters. Patients with high myopia have a 98% chance of seeing 20/40 or better after the initial procedure and an 85% chance of seeing 20/20. Including enhancement surgeries, they have a greater than 99% chance of seeing 20/40 or better and a 95% chance of seeing 20/20 or better.
If the sphere part of your eyeglass prescription is more than -11.00, you have extreme myopia. Patients with extreme myopia have a 94% chance of achieving 20/40 vision or better after the initial procedure. Including enhancements, 90% of patients will have 20/20 vision or better.
Many patients with extreme myopia do well with LASIK, but we do not consider them optimal candidates. After LASIK, patients in this range are more likely to have enhancements and more likely to have problems with quality of vision, such as glare, halos or hazy vision. Patients in this group need to thoroughly discuss the risks and benefits of LASIK, as well as other options, with their doctors. Although enhancement rates are higher in this group of patients, because of other variables in the eye, there may be limitations on what can be done. Most surgeons do not generally recommend PRK for these patients, who may be better candidates for the implantable contact lens.
Hyperopia (Low and Moderate Hyperopia)
If the sphere part of your eyeglass prescription is a positive number, you have farsightedness, or hyperopia. If the number is between 0.00 and +4.00, you have a low to moderate level of hyperopia. After your initial LASIK or PRK procedure, you have a 95% chance of achieving 20/40 vision or better and a 75% chance of achieving 20/20 vision.
Patients treated for hyperopia should be aware that their healing time will be slightly longer than for patients with myopia, and the chance that they will need an enhancement is slightly higher. These number will vary according to the patient’s original prescription and the skill and experience level of the surgeon.