How laser eye surgery vision correction works:
The planned correction is programmed into the laser's computer. The laser gently sculpts the corneal surface. The cornea is sculpted in a pattern which corrects your vision error.
In myopia correction, the center of the cornea is slightly flattened. This brings the focus back to the retina of a long, nearsighted eye.
In hyperopia the cornea around the central zone is flattened. This steepens the central cornea, bringing the focus forward to the retina of a short, farsighted eye.
In astigmatism an oval reshaping is performed to make the eye more round.
LASIK laser eye surgery procedure
- A thin flap, slightly thicker than a human hair, is created. It looks like a perfect soft contact lens. The flap is moved to the side temporarily.
- The excimer laser removes a minute amount of the cornea beneath the flap. The thickness removed is thinner than a human hair. The pattern of cornea removed depends on the correction necessary.
- The flap is placed back over the cornea. The treated area is completely covered with the flap. The cornea has tremendous bonding characters and the flap adheres securely in minutes.
PRK laser eye surgery procedure
Photo-refractive keratectomy (PRK) - similar to LASIK except there is no flap creation. Instead of creating a flap as in LASIK, the surface cells are removed with the laser or a special instrument, then the laser thins and reshapes the cornea just as with LASIK.The surrounding surface cells must grow back over the center zone of the cornea so healing in terms of comfort and vision is longer than with LASIK.
In LASIK the flap covers the area of treatment immediately after the laser treatment. In PRK it is covered with a contact lens until the surface cells heal in completely. The long term results of PRK are similar to the LASIK procedure.
The laser eye surgery experience
The laser procedure is performed at a local laser center. You wear normal street clothes. Drops are the only anesthesia. Sedation is not necessary, but you may take an oral tranquilizer.Your eyelids and lashes are cleansed for sterility and a sticky drape keeps your lashes out of the way. Your lids are gently opened with a special retracting instrument. You look at a blinking red light which helps to keep your eye properly positioned. The laser also has special tracking technology that follows even the tiniest of natural eye movements.
During the flap creation phase you have a sensation of pressure and a grayness of vision. Then the laser is used and you will hear a rapid clicking sound. The flap is replaced and it takes about 2 minutes for it to stick down. Drops are placed in your eyes to aid healing and clear protective eye shields are placed over your eyes. The procedure takes under 10 minutes per eye.
LASIK and PRK laser eye surgery recovery
Discomfort is rare and minimal. Usually vision is immediately improved but may fluctuate for several weeks. For a week a shield is worn over the eye at night until complete healing occurs. The eyes and lids cannot be rubbed to protect the flap.
Drops are used for 1 week or less with LASIK, and up to several weeks with PRK. Retreatment occasionally is necessary and is performed as soon as the eye is stable but usually no sooner than three months.
Laser eye surgery expectations
Laser vision correction is an exciting procedure which greatly reduces ones dependencies on glasses and contact lenses. LASIK is a liberating procedure - it usually results in a dramatic life change for the person. Between 95% and 98% of the patients achieve legal driving vision without glasses (20/40 or better), and 2/3 of those patients will see 20/20 or better.
As with any surgical procedure there are risks, but the complication rate is very low. The LASIK procedure is quite controlled and uses the advanced technology of computers and lasers.
Glasses may be necessary for fine tuning vision for certain conditions (night driving, computer work, heavy reading). People over forty usually require reading glasses unless one eye is purposefully made nearsighted (this blurs that eye for distance to achieve a " one eye far, one eye near situation," or "monovision".
Most people prefer both eyes as sharp as possible for distance and the use of reading glasses when necessary.