Myth:	Everyone who has refractive surgery will achieve 20/15.
Fact:	Surgeons aim for results of 20/20 or better so that you can perform most daily activities without your glasses. However, there is a possibility that after surgery, you may need to wear reading glasses or corrective lenses for at least some activities.
Myth:	LASIK gives everyone perfect vision.
Fact:	Most patients who have LASIK will have better vision without glasses after the procedure, but LASIK does not guarantee perfect vision.
Myth:	Everyone who has LASIK will achieve 20/20.
Fact:	Approximately 56% of all patients achieve results of 20/20 or better and over 90% achieve 20/40 or better (which is good enough to drive without corrective lenses in most regions).1 Those with moderate to high myopia (greater than 7 diopters) have a lesser chance of achieving that result. As technique and technology improve, the results continue to improve.
Myth:	If I do achieve 20/20 after LASIK, I will have perfect vision.
Fact:	While visual acuity (20/20, 20/40, etc.) is a useful clinical test of vision, it is not the only measure of vision. For example, eye charts do not assess sensitivity to different shades of gray, how your vision is affected at night or in dim light, or how effectively your eyes change and maintain focus. Patients must understand that "20/20" does not mean "perfect" vision and should not become focused with achieving this number. They should remain focused on the goal of refractive surgery - reducing a patient's dependence on glasses or contacts.
Myth:	If I don't achieve 20/20 vision, I will not be satisfied with the surgery results.
Fact:	Patients should not confuse achieving 20/20 with final satisfaction with the procedure. It's important to note that several studies have reported both the final visual acuity (20/20, etc) and patient satisfaction. While they report a range of 80-95% achieving 20/40 or better, 90-97% were highly satisfied and would have the surgery again.2-7

Patients should understand that having expectations that are realistic for their particular case is most important to their ultimate satisfaction with the results of the procedure. While we provide general statistics below, it is important for patients to talk with their doctors and review their expectations prior to making a final decision.

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 most regions, this is good enough to drive without having to wear contact or glasses. The same study found that 45% of eyes achieved 20/20 or better at one month post-operatively. This number climbed to 50% at six months post-operatively. According to the LASIK studies submitted to the US FDA, an average of 56% achieved 20/20.¹
Nevertheless, as with all refractive surgeries, patients may still need to occasionally wear corrective lenses to achieve sharpest possible vision.

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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. Several studies, both within the US₁ and internationally ^6,8,10-11 demonstrate that LASIK for higher degrees of myopia can be effective. However, highly myopic patients need to understand that they should aim for 20/40 not 20/20, 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.

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.^12-22 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.Patients should be aware that, in the United States, LASIK for hyperopia is an off-label procedure on a number of excimer lasers, and treating hyperopia in conjunction with more than 1D of astigmatism is not permissible outside of clinical trial settings on some machines. For more information regarding FDA approval, visit http://www.fda.gov/cdrh/lasik/lasers.htm. Patients in other countries should be sure to check with their country's ophthalmic society regarding regulatory status.

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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.

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Monovision

Sometimes 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.

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Other Issues

Enhancements

Patients may need additional procedures called enhancements. Studies have indicated that enhancements (or retreatments) are performed in approximately 8-17% of cases.¹ However, patients should understand that there are many reasons for an enhancement. For example, in cases where a great deal of correction is required, a surgeon will sometimes purposefully undercorrect a patient's eye and perform an enhancement procedure at a later date. You should discuss the anticipated course of action and possibility of the need for an enhancement with your surgeon.

Speed of Visual Recovery

Patients should understand that, while fast visual recovery characterizes the operation, it can take several months before some patients achieve their final vision after LASIK. Several studies^1,9 demonstrate that the vision of a number of patients continued to improve up to six months post-operatively.

Crispness of Vision

Patients need to understand that, for many people, 20/20 vision after LASIK can be different from 20/20 vision with contact lenses before LASIK, especially gas permeable contact lenses. The images seen through eyes treated by LASIK are often described as not being as "crisp" as those seen through glasses. This condition, referred to in ophthalmic literature as "loss of contrast sensitivity," will not affect your acuity as it is measured on an eye chart, but the visual experience is different enough that a new term has been coined: LASIK 20/20. While the majority of patients do adjust to this change following LASIK, patients who perform fine detail work (artists, architects, draftsmen) should be sure to carefully weigh the benefits LASIK can afford against the potential loss of contrast sensitivity.

Visual Quality

Finally, most improvement in refractive error is measured in terms of Snellen lines on an eye chart. However, the quality of one's vision cannot be measured solely by this means. Some patients may experience diminished night vision, starbursts or halos after having the surgery, and this experience is not measurable with an eye chart. These symptoms usually subside within one month to 6 weeks for the vast majority of patients who experience them. However, some will continue to experience them for a greater length of time. The change in visual quality has been reported widely in the last few years. It is important for patients to understand there is a risk that they may experience some of the symptoms listed above and that the change can have an impact on their life. However, it is equally important for them to understand that the majority of patients who've had the surgery report no change in quality of vision and some even experienced a decrease in symptoms.¹ The FDA required that all studies submitted to them regarding the safety and efficacy of excimer lasers for refractive surgery include pre- and post-operative patient surveys. Patients within the studies reported their subjective experience with such visual quality issues as glare, halos, diminished night vision, etc. It is important for all patients who are concerned about this to talk with their doctor about their expectations and concerns.

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