LASEK - laser eye surgery > LASEK procedure

The LASEK (laser eye surgery)  procedure is performed as an ambulatory surgery. The patient lies on the comfortable table. The surface of his eye is completely numbed by the anaesthetic drops. The eye and its surroundings are covered by a sterile surgical dressing. A small lid speculum is fitted on the eyelids to prevent the eye from blinking during the procedure.

During the LASEK procedure, the surgeon removes the microscopic pieces of the tissue from the surface of the eye by excimer laser. LASEK is less invasive than LASIK because it reshapes only the outer layers of the cornea.

LASEK uses an epithelial flap. At the beginning of the procedure, the marker in the shape of a ring is placed on the surface of the cornea and subsequently is filled with an alcohol for a short period of time (for about 30 seconds). Then the alcohol is sponged off and the cornea is rinsed out. The epithelium is gradually separated from the eye till the whole lamella is separated. Then laser photoablation is performed.

Laser photoablation

During the laser photoablation, the required amount of the tissue also known as stroma of the cornea is being removed. In correction of short sightedness, the central part of stroma is removed so the curvature of the cornea is straightened. In correction of long sightedness, the peripheral part of stroma is removed so the curvature of the cornea is thus maximized. When astigmatism is being corrected, the laser straightens the inconsistent curvature of the cornea by removing the tissue.

Very important is also the evaluation of the permissible depth of photoablation. The most common depth of lamella is 160 micrometers (or 130 to 180 micrometers) and not photoablated cornea should have at least 250 micrometers. The photoablation uses a system of dancing beam of light which is also known as "dancing point". In this technique the frequency of pulses is approximately 25 Hz and the trace of pulse is 1-2 mm. The soft and precise shape of cornea is achieved after the repetition of the particular photoablations.

The recovery and regeneration of epithelium takes place during the period of few days. The micro-layer of stroma which is removed by laser does not regenerate and holds new shape of cornea. Laser usually removes 5 to 15% of the depth of stromal cornea.
The period of laser energy application is usually shorter than 1 minute and the whole LASEK procedure of one eye lasts usually 5 to 15 minutes. Thanks to its wave length, beams of excimer laser do not penetrate through the cornea and thus the tissue of the inner eye is protected. The structural integrity of the eye is thus not changed.

At the end of the eye surgery procedure, the surgeon places a special bandage contact lens on the eye in order to secure it in the first days of recovery.