What is the enhancement rate / success rate?

    A LASIK enhancement is a fine-tuning of the original procedure should there be any residual prescription that produces less than desired visual outcome.  An average of 5-10% of surgeries need an enhancement.  A surgeon’s “enhancement rate” ideally should be a reflection of the results of the original procedure.  Unfortunately, there are several variables that can make this difficult to interpret.  For example, surgeon #1 may choose to enhance even the slightest residual prescription so as to provide the patient with optimum vision and an excellent experience.  Surgeon #2 may choose not to enhance except when the patient insists that their vision is not satisfactory.  Obviously surgeon #2 can boast a lower enhancement rate than surgeon #1, even with identical outcomes with the original procedure.  Our experience is that there is greater patient satisfaction when enhancements are safely performed as necessary, and not reserved for only the most dramatic residual prescriptions.

    Higher and more complex prescriptions, corneal hydration, health, gender, pupil size, and corneal shape all influence odds of needing an enhancement.  The potential for any given patient needing an enhancement procedure cannot be accurately determined from a person's eyeglass prescription.

    In addition, many patients like to ask about the "success rate" for LASIK. This is a challenging question to provide a simple answer to simply because it is difficult to determine what the person asking the question means by "success".  Since there is no medical terminology by which we define success, the question is highly ambiguous.  For example, one aspect of "success" is to consider how many patients are able to function without glasses or contacts after LASIK.  If we measure by ability to function, then basically 100% are successful.  A second determination of success could be by the number of patients who had no complications.  However, there are numerous patients that have endured minor or even major complications that are ecstatic with their vision when the healing process is completed.  Are these patient's outcomes to be considered "successful" or "unsuccessful"?  A third consideration is what percentage of patients need an enhancement to fine tune their vision.  As noted previously, enhancement rates vary considerably based upon the surgeon’s particular enhancement bias, the patient’s prescription and other details of the eye's health.  All of these factors make providing an answer to such a vague question in a coherent and concise manner impossible.

    Part of the visual results a person achieves from LASIK depends on the healing process after the surgery itself.  Your present prescription lies somewhere on a mathematical number line.

-10   -9   -8   -7   -6   -5   -4   -3   -2   -1    0   +1  +2   +3   +4   +5   +6   +7   +8   +9   +10

          (nearsightedness)                       desired                      (farsightedness)

    You will be intentionally overcorrected from your prescription past the zero point and shifted into the opposite prescription a slight amount.  The reason for this is because as you heal, your vision will slide backwards slightly towards the prescription you began with.  The goal is to heal back to the zero point on the number line, which means no residual prescription.  The amount you will be overcorrected from nearsightedness into farsightedness (or vice versa) is relative to the average amount a person with your prescription will slide backwards while healing.  However, if you happen to heal faster or slower than that average, you may end up on either side of the desired zero point and have a bit of residual prescription.  The higher or more complicated the prescription, the greater the odds of not drifting precisely to the zero point.   If this occurs and the resulting visual acuity is not satisfactory, an enhancement can be performed at three to six months from the original surgery.  An enhancement involves re-lifting the original flap and treating the residual prescription with the laser if there is adequate corneal tissue.

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