Patients considering LASIK to address vision problems will first have their eyes examined to determine their suitability for the procedure and to see if there is any disease or other condition present, that could negate the advisability of having the surgery. The doctor will use the exam to determine what kind of vision correction is needed, and how much laser ablation is required to achieve the desired result. A corneal topographer may be used to photograph the eye and create a detailed “map” to guide the surgeon in making the proper adjustments during the procedure.
People both nearsighted and farsighted can benefit from LASIK. Nearsightedness is corrected by flattening a too-steep cornea; with farsighted people, a steeper cornea is desired. While it is not widely recognized by many, Excimer lasers can also correct astigmatism by smoothing an irregular cornea into a more normal shape.
The standard LASIK procedure is ambulatory; patients walk into the surgery center, have the procedure and walk out again. In fact, the actual surgery usually takes no more than five minutes, and the patient remains awake the whole time. In some cases, the surgeon may administer an oral sedative to help patients relax before the procedure.
After anesthetizing the eyes with special drops, the surgeon will place the patient face-up directly beneath the laser, with a kind of retainer used to keep the eyelid open during the procedure. Normally, this is not uncomfortable. The retainer has a suction ring that keeps the eye pressurized, which is important in LASIK to allow the surgeon to cut the corneal flap.
The surgeon will then use an ink marker to mark the cornea before the flap is created. The flap is then created with either a microkeratome or with a laser, depending on the surgeon’s preference.
Using a computer to adjust the laser for the patient’s prescription, the surgeon will have the patient look at a target light for a short time while the doctor watches the eye through a microscope and the laser sends pulses of light to the cornea.
Laser light pulses then painlessly reshape the cornea. Patients will hear a steady clicking sound as the laser is operating and may smell a mildly acrid odor due to the removal of tissue. The surgeon has full control of the laser and can turn it off at any time. Once the adjustments to the cornea are complete, the surgeon replaces the previously cut flap, which acts as a kind of natural bandage and is self-healing.
In most cases, if both eyes are being done, the surgeon will ask the patient to rest for a short time between sessions with the laser. Some patients choose to wait a week or so between sessions.