What is LASIK?
Laser in situ keratomileusis, or LASIK, is an outpatient surgical procedure used to treat myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. With LASIK, your ophthalmologist (Eye M.D.) uses a laser to reshape the cornea (the clear covering of the eye) to improve the way the eye focuses light rays onto the retina.
How is LASIK done?
LASIK is performed with the patient reclining under the laser in an outpatient surgical suite. First, the eye is numbed with a few drops of topical anesthetic. These drops may sting. An eyelid holder (called a speculum) is placed between the eyelids to keep them open and prevent you from blinking.
A suction ring placed on the eye lifts and flattens cornea and helps keep your eye from moving. You may feel pressure from the eyelid holder and suction ring, similar to a finger pressed firmly on your eyelid. From the time the suction ring is put on the eye until it is removed, vision appears dim or goes black.
Your ophthalmologist may use an automated microsurgical instrument called a microkeratome or a laser to make a flap in your cornea. This device is attached to the suction ring. As the microkeratome blade moves across the cornea, you will hear a buzzing sound. The microkeratome stops at a present point, far enough from the edge of the cornea to create a hinged flap of paper-thin corneal tissue. The microkeratome and the suction ring are removed from your eye, and the flap is lifted and folded back.
Some ophthalmologists use a specific laser instrument instead of a bladed microkeratome to make the flap in your cornea. With this technique, tiny, quick pulses of laser light are applied to your cornea. Each light pulse passes through the top layers of your cornea and forms a microscopic bubble at a specific depth and position within your cornea. You Eye M.D. then creates a flap in the cornea by gently separating the tissue where these bubbles have formed. The corneal flap is then folded back.
As the flap is moved aside, your vision gets blurrier. Then a special laser for sculpting the cornea- preprogrammed with measurements customized to your eye- is centered above the eye. In most cases, a pupil tracker will be used to keep the laser centered on your pupil during surgery.
You will stare at a special pinpoint light called a fixation light or target light while the laser sculpts the exposed corneal tissue. The laser makes a clicking sound you can hear during the procedure. After the laser has completed reshaping the cornea, the surgeon places the flap back into position and smoothes the edges. The flap adheres on its own in two to three minutes.
PRK is an outpatient surgical procedure performed under topical anesthetic eye drops. The epithelium or the outermost layer of the cornea is removed with a blade, alcohol, or laser. An Excimer laser is then used to remove a thin layer of corneal tissue. The laser sculpts the surface of the cornea. By reshaping the cornea, the refractive error is illuminated and the need for contact lenses and glasses is greatly reduced or eliminated. Because no incisions are made the cornea is not weakened. Immediately after surgery the eye is patched for usually four days with a bandage contact lens until the epithelium has recovered. It may take several weeks to achieve your best vision.