Epi-LASiK (Epithelial Laser In Situ Keratomileusis) is usually performed as an outpatient procedure using topical anesthesia with eyedrops. Your ophthalmologist (Eye M.D.) uses an alcohol solution to loosen and peel back the epithelium, the outermost layer of the cornea, to expose the corneal tissue beneath it. A cool excimer laser is used to permanently reshape the cornea, and the epithelium is either placed back into position, where it will selfadhere, or is removed completely, in which case the epithelium heals inward from the corneal periphery in just a few days. The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: They are myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common.
Light rays are focused in front of the retina instead of directly on the retina
Light rays are not bent enough to focus directly on the retina
Light rays are focused at more than one point on the retina
The Cornea is reshaped so light rays can focus directly on the retina
To treat nearsightedness, the cornea is made flatter by removing tissue from the center of the cornea. To treat farsightedness, the flat cornea is made steeper by removing peripheral tissue in a ring shape on the outer edges of the cornea. This steepens the central visual part of the cornea. To treat astigmatism, the cornea is made less oval shaped. Astigmatism means that the eye has an oval or football shape. The laser reduces the oval shape making the focusing ability clear in all directions. Astigmatism can be treated at the same time as nearsightedness and farsightedness.
Visual recovery after epi-LASiK is generally faster than in PRK, a little faster than LASIK, but faster than Lasek.
This type of laser vision correction does not require any corneal incision at all. A mild alcohol solution is placed on the corneal to loosen the top layer of tissue. Only the most superficial layer of the cornea is gently brushed aside. This thin flap is then replaced after the laser reshaping is complete. Less tissue is removed than with traditional Lasik. A contact lens is placed on the cornea shortly after surgery as a bandage for several days to aid in the healing process. It normally takes three to ten days for the epithelium to heal and resurface the cornea. This healing time varies depending on a number of factors such as the size of the area treated, the health of the patient's cornea and the individual's own healing rate.
