Various guidelines recommend patients be at least either 18 or 21 years old to have LASIK. A more important criteria, however, is that your eyes be stable in their prescription before you undergo LASIK.

One question I am frequently asked is what the youngest age is that patients can have LASIK. Some guidelines suggest 18 is the yougest age to have LASIK, while other guidelines suggest 21. In fact, there really isn’t a specific number. I personally recommend that patients ideally be 18 to 21 or older and be stable in their prescription. It is the stability of prescription, rather than the actual age, that is the more important issue.

In general, your prescription tends to get worse every year similar to the way your shoe size gets bigger every year. At some point, however, just as your shoe size finally stabilizes and stops changing, your prescription will also stabilize and stop changing. Typically this happens somewhere in your early twenties, although some people stop changing much earlier and others continue to change even into their thirties, although this would be quite rare.

It is important to understand that LASIK does not stop future changes in your prescription from occuring — it simply “resets” your vision back to “zero.” If you are still changing when you have LASIK, then your vision will continue to worsen and it will appear that your LASIK is wearing off. In fact, your LASIK would not be wearing off at all. It would simply be the case that the “prescription” in the LASIK would no longer be strong enough for your now increased need. It is for this reason that I recommend that young patients wait until their eyes have stopped changing before undergoing LASIK.

Interestingly, the definition of stability for your eyes varies. The FDA, in some of its guidelines, has suggested that no more than 1 diopter of change over the past 12 months indicates stability. I personally prefer a more conservative definition and recommend no more than 0.50 diopters change over 12 to 18 months to indicate stability.

It is important to understand that most people will be looking at their glasses or contact lens prescriptions which are derived from a refraction — the “which is better, one or two” test. Because this test is itself subjective and often confusing, there is an inherent level of inaccuracy in this test. Most experts feel the refraction test is accurate only to +/- 0.50 diopters, meaning that you could take this test two days in a row and get a result that differs by 0.50 diopters, even though your eyes didn’t actually change over those two days! It is for this reason that I personally use the criteria of no more than 0.50 diopters of change over 12 – 18 months as an indication of stability.

It is also important to know that we are not made out of marble and steel and that, even after your prescription has stabilized, there can be long term small changes in your eyes that LASIK will not prevent from happening. These are changes that would be expected to happen whether or not you have LASIK. In general, there never is a fool proof way to guarantee stability.

Often, for an 18 year old who is eager to have LASIK, waiting for the eyes to stabilize can be a frustrating experience that can seem to take an eternity. Nevertheless, it is important to wait until your eyes do stabilize before undergoing LASIK.

See Also

FDA LASIK website
The FDA’s website with information for the public about LASIK eye surgery.