• What Is Small Incision Lenticule Extraction?

    Written By:
    Reviewed By: James M Huffman, MD
    Apr. 29, 2020

    Small incision lenticule extraction (SMILE) is a newer type of laser refractive surgery. This kind of surgery uses a laser to treat myopia (nearsightedness) and astigmatism (irregularly shaped cornea).

    For you to see clearly, light rays must travel through your cornea and lens. The cornea and lens refract (bend) the light so it lands on the retina. With a refractive error, the shape of your cornea or lens keeps light from bending properly. When light is not focused on the retina as it should be, your vision is blurry.

    With SMILE, your ophthalmologist uses a laser to change the shape of your cornea. This improves the way light rays are focused on the retina. SMILE is FDA-approved to treat mild nearsightedness and astigmatism.

    The goal of SMILE is to correct your nearsightedness, astigmatism, or both, to improve your vision. SMILE may reduce your need for eyeglasses or contact lenses. In some cases, it may even allow you to do without them completely.

    Who is a good candidate for SMILE?

    If you have an active lifestyle or job, SMILE may be a better option for you than LASIK or similar procedures. This is because SMILE does not involve cutting a flap in your cornea like LASIK. If you are highly active, you could accidentally dislodge a corneal flap, causing problems.

    To have SMILE, you need to meet certain requirements. Here are some of them:

    • You should be 22 years or older.
    • Your eye prescription should not have changed in the last year.
    • You should have nearsightedness between -1 and -10, and up to 3 diopters of astigmatism.
    • Your corneas need to be healthy, and your overall eye health must be generally good.
    • You need to have realistic expectations about what SMILE can and cannot do for you.

    Some people are not candidates for SMILE. They include people with: 

    • an unstable (changing) refractive error
    • skin or other disease that can affect healing
    • excessive scarring or keyloid formation
    • cornea abrasions or disease
    • advanced glaucoma
    • a cataract affecting vision
    • uncontrolled diabetes
    • a history of eye disease or eye surgery
    • history of certain eye infections
    • or who are pregnant or nursing

    Your ophthalmologist can talk with you about other conditions that may keep you from having SMILE.

    To determine whether you are a candidate for SMILE, your ophthalmologist will examine your eyes. Here’s what he or she will do:

    • Check the overall health of your eyes
    • Measure your cornea
    • Check your pupil size
    • Measure your nearsightedness and astigmatism