From Troy Bedinghaus, O.D.,
Your Guide to Vision.
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About.com Health's Disease and Condition content is reviewed by Kate Grossman, MD

Perfect Vision? No Guarantee

LASIK will almost certainly reduce your dependence on glasses and contact lenses, but there is no guarantee that you will have perfect vision without glasses. While perfect vision is the optimal outcome of LASIK, whether or not you receive it depends on your individual experience. Everyone's eyes and vision are unique. What works for some may not work for others. Success in LASIK depends on the individual. Your personal eyeglass prescription can tell a lot about how you may respond to LASIK. The higher your prescription, the lower the chance of a perfect outcome. Your doctor will study all of your health data and will be able to give you an educated guess on your expected outcome. Every individual is unique...problems will occur in any field of health if a medical professional views every patient in the same way.

Consider Your Expectations

Your potential vision also depends on the quality of vision that you would like to have, depending on what types of visual activities you do everyday. Do you wish to be able to see the alarm clock without slipping on your glasses, or do you need to be able to see clearly through an archery scope lens? Desirable expectations should be thoroughly discussed with your doctor in order to realistically assess your chances of a successful outcome. Your ultimate satisfaction with your results of LASIK depends mostly on having realistic expectations for your individual case. Before making a final decision, be sure to talk with your doctor about how well you truly expect to see after surgery.

"20/20" Vision Doesn't Mean "Perfect" Vision

Today, most patients can expect to have close to 20/20 uncorrected vision. In fact, many patients are ending up with 20/15 or better vision. However, most refractive surgeons will require a consent form with a disclaimer that the procedure is designed to "reduce your dependency on eyewear." This is a fair statement and should be taken seriously. Doctors can never guarantee that you will end up with perfect vision. Based on experience, most patients receive "20/HAPPY vision." This means that your vision may not be exactly perfect, but you can enjoy 95% of your daily activities without corrective glasses or contact lenses.

Be aware that the typical Snellen eye chart (the one with the big E at the top) is only one measurement of vision clarity. You may be able to read the very bottom line on the chart, but still not see clearly -- you could have debilitating problems such as halos around lights, glare, filmy vision or very dry eyes that decrease the quality of your vision. Try not to become focused with achieving the magic number of 20/20. Instead, focus on the goal of your surgery: to reduce your dependence on glasses or contacts.

Typical LASIK results:

• 95% of patients have 20/40 or better vision
• 85% of patients have 20/20 or better

Note that some of these studies do not take into consideration one’s unique physiology and requirements. Of course, this varies depending on the research study that was conducted. The FDA classifies LASIK results based on what brand or type of laser was used.

_{Source: Azar, Dimitri T. and Douglas D. Koch. "LASIK: Fundamentals, Surgical Techniques, and Complications." Marcel Dekker, Inc., pp 277-280. Copyright 2003.}