Laser eye surgery is a common method of vision correction. Many people seek it in order to free themselves of glasses or contacts. However, depending on one’s prescription, eligibility, choice of surgical procedure and outcome can vary and it is important to keep expectations as realistic as possible. In certain cases, if you are only slightly nearsighted, it may actually be desirable to keep this prescription so that you are less dependent on reading glasses later in life. Explained below are three very common refractive procedures. It is worth mentioning that there are other less common methods that your eye doctor can discuss with you if you have specific needs or concerns.
Laser-Assisted in Situ Keratomileusis (LASIK)
LASIK is the most common procedure for refractive surgery. It can be used for a large range of nearsightedness and astigmatism, and a smaller range of farsightedness. In the surgery, a “flap” of the clear front of the eye, the cornea, is first created using either a laser or a very precise blade. This is then hinged off the cornea, like opening a manhole cover, to reveal the tissue deeper in the cornea. It is this tissue that is actually carved away using a laser to create the desired prescription. Throughout these steps, the eye is held with suction so that it does not move excessively and a computerized tracker ensures that the laser does not fire unless it has a lock on where the eye is. After the laser carving, a step that takes less than one minute, the flap is closed and irrigated with fluid as it reattaches to the rest of the cornea. LASIK has a very quick recovery – you will notice even leaving the appointment that your vision is much improved and you can likely drive the following day. However, because a flap is created, there is the potential for the flap to reopen if there is trauma to the eye.
Photorefractive Keratectomy (PRK)
PRK is the precursor to LASIK and is still used in many cases when LASIK is not an appropriate option. This can occur for a number of reasons, such as in patients with very high prescriptions or thin corneas. It covers a lower range of refractive errors than LASIK and has a longer recovery period. It differs from LASIK in that a flap of the cornea is not cut; rather, the outer layer of the cornea is simply brushed off. The laser is then used to carve out tissue to the desired prescription, as in LASIK. PRK has the advantage over LASIK that flap complications are not possible and the cornea is not weakened by the process, but has disadvantages in that it achieves less consistent results and has a longer, more painful, and more gradual recovery than LASIK (2-3 weeks before vision is fully recovered).
Small Incision Lenticule Extraction (SMILE)
SMILE is the newest and commonly performed refractive surgery in this list. It is similar to LASIK in that the treatment is used on the inner cornea, but differs in that there is no flap creation. A laser is used to fully cut a disc of the inner cornea from the rest and then this is removed through a small incision to leave the cornea at the desired prescription. It has faster corneal healing and is a quicker procedure than LASIK, but is slightly less effective. Risk of complications are similar between SMILE and LASIK.