Here is a summary of the generally current results from large clinical studies on LASIK. This should tell you something about the likelihood of the results in your own case.
Myopia (Nearsighted) & Myopic Astigmatism
LASIK improves the uncorrected vision – how a patient sees without corrective lenses – in most patients who have the procedure, but it does not guarantee perfect vision. The large majority of patients who have LASIK will be able to see well without corrective lenses. According to the figures provided by CRS-USA9 (which considered 1,736 eyes with myopia and myopic astigmatism (up to -14D of myopic error and 6D of astigmatism), approximately 87% of eyes that had LASIK achieved 20/40 or better one month post-operatively. By six months, 93% of eyes achieved 20/40 or better. In the latest clinical studies for USFDA approvals for the Zeiss and Wavelight Lasers, more than 90% of the patients were 6/6 or better after LASIK for low to moderate myopia. This is really quite remarkable.
Nevertheless, as with all refractive surgeries, patients may still need to occasionally wear corrective lenses to achieve sharpest possible vision.
High Myopia (Very Nearsighted)
In general, patients whose eyes are characterized by higher degrees of myopia may need to have a different set of expectations regarding outcomes. They may also wish to consider alternatives to LASIK, like an Intraocular Contact Lens (ICL) or Clear Lens Extraction with Multifocal Lens Implant.
Several studies, demonstrate that LASIK for higher degrees of myopia can be effective. However, highly myopic patients need to understand that they should aim for 6/12 not 6/6, that there is a slightly higher incidence of regression and that the goal of the surgery will most likely be for the patient to be within one diopter of emmetropia.Patients should talk with their surgeon to best understand what expectations they should have.Additionally, studies have noted a slightly higher risk of complications in highly myopic patients; therefore patients may wish to review this with their surgeon. Please also note that all lasers are not FDA approved for high myopia. Sometimes this is because they gave bad results for high myopia. Most times, however, it is because they were not studied in that range.
Hyperopia (Farsighted) & Hyperopic Astigmatism
Patients whose eyes are characterized by hyperopia need to have a different set of expectations regarding outcomes than myopes. Typically, the visual recovery of hyperopic patients is not as quick as that experienced by myopic patients. Consequently, the surgeon may discuss a surgical plan that calls for operating on the one eye then wait a few days to several weeks before operating on the second eye. Overall, studies have shown that the six month post-operative results are similar to those achieved for myopia. However, there may be a slightly higher incidence of regression associated with the procedure. As with myopia, those with lower levels of hyperopia experienced slightly better overall results than those with high hyperopia. It is therefore important for patients to discuss the expectations with their ophthalmologist after full examination of their eyes.
Presbyopia
If you are over 40 years old, you should understand that if you are corrected for excellent distance vision, you might have to give up some of your close vision. This happens because presbyopia affects people as they enter their 40s. Presbyopia, caused by the changes within the eye’s crystalline lens as one ages, affects everyone, and eventually everyone will need to wear reading glasses. LASIK does not prevent the onset of this condition nor does it treat it. Therefore, surgeons aim for a balance between good distance vision and good close vision. It might be helpful to think of what happens when you take a picture with a manual focus camera to understand what surgeons do. If you adjust the lens to bring an object in the distance into focus, that object becomes very crisp while the images closest to you become fuzzy. Conversely, if you adjust the lens to bring an object in the foreground into focus, that object becomes very crisp while the background becomes fuzzy. However, if you focus on the middle ground, you can see the foreground and the background relatively well.
Monovision
Most times, conditions particular to a patient’s eye make achieving such a middle ground difficult. In such cases, the surgeon may discuss the option of purposefully designing the procedure to leave one eye slightly nearsighted so that the eye may be used for reading. The opposite eye is adjusted to have better vision at distance. This condition is called monovision. Although monovision proves to be satisfactory for the majority of patients, some are not comfortable with this arrangement. Patients need to discuss the options with their physicians.
