AUSTIN EYE CLINIC
AUSTIN LASER AND REFRACTIVE CENTER
Other Procedures: LASEK, PRK, SRP, etc.
LASEK: LASEK (Laser ASsisted Epithelial Keratomileusis)is a modified form of LASIK and PRK. LASEK is also known as “Epi-LASIK.” During LASEK, a thin flap from the epithelial or superficial layer of the cornea is created. The laser is applied to the corneal bed which becomes exposed after the flap of epithelium is reflected. After laser ablation to reshape the cornea, the epithelial flap is repositioned to cover the ablated area followed by application of a soft contact lens. The epithelial flap is approximately 50 microns in thickness. The standard corneal flaps measure 100-160 microns in thickness.
The Advantages of LASEK: 1) Ability to treat individuals with thinner than average corneas, 2) less risk of standard LASIK corneal flap complications
The Disadvantage of LASEK: 1) Slower healing time and more discomfort than LASIK, 2) retreatments are painful and recovery slow again, 3) chance of corneal scarring.
PRK: PRK (Photorefractive Keratectomy) was the first corneal procedure upon which FDA approval was given for the first generation of FDA approved excimer lasers. PRK involves complete removal of the corneal epithelium (surface layer of the cornea) followed by application of the excimer laser to the exposed corneal surface. The epithelium regenerates over a period of 3-5 days. The visual outcomes between LASIK and PRK are virtually equivalent. LASIK is preferred however due to the quicker recovery.
The Advantage of PRK is that there is no flap and therefore no flap complications.
The Disadvantages of PRK: 1) a lot of pain and slow recovery of vision, 2) retreatments are painful and recovery slow again, 3) chance of corneal scarring.
REFRACTIVE LENSECTOMY: Refractive lensectomy (aka clear lens exchange) is basically cataract surgery in the absence of a cataract. Patients who are candidates for refractive lensectomy surgery have high degrees of near or far-sightedness that are beyond the limits correctable by LASIK or other corneal surgeries. In this procedure, the natural crystalline lens of the eye is removed and then a new artificial lens implant of a prescribed new focusing power is inserted into the eye. Vision is improved because the new artificial lens allows better focus for the eye than the original lens. Presbyopia can be corrected by use of multifocal or accommodative lens implants such as the Crystalens/Restor and Rezoom lenses.
RADIAL KERATOTOMY: Radial keratotomy (RK) was one of the most widely performed procedures for correcting low degrees of myopia. In the myopic eye the light rays are focused in front of the retina. By flattening the cornea the light rays are focused on the proper plane of the retina. Radial keratotomy has been performed since the early 1970's. The technique of radial keratotomy has undergone progressive refinements in both the technology and methodology. Radial keratotomy consists of making a radial pattern of incisions around the optical zone of the cornea allowing the cornea to flatten thereby correcting the myopia.
ASTIGMATIC KERATOTOMY: Astigmatic keratotomy (AK) is a modified form of radial keratotomy designed to correct astigmatism. A cornea with astigmatism has two different radii of curvature. A diagrammatic representation would be that the cornea is shaped like a football with one curve being more steep than the other. When astigmatic keratotomy is performed, incisions are made at the periphery of the cornea which allow the football-shaped cornea to round up like a basketball thereby reducing or eliminating the astigmatism. Astigmatic keratotomy is frequently performed in combination with radial keratotomy or with laser vision correction.
Differences between PRK, LASIK and LASEK
| PRK | LASIK | LASEK | ||
|
||||
| Range of correction | Low to Moderately high | Low to Moderately high | Low to moderately High | |
| Wound Depth | Superficial (remove epithelium) | 20% depth (flap preserves epithelium) | Superficial (epithelium flap) | |
| Intraoperative Pain | None | None | None | |
| Postoperative Pain | Moderate 24-48 hrs. | 3 to 6 hrs. | Mild to moderate 24-48 hrs. | |
| Postoperative Medications | 3 weeks to several months | 1 to 2 weeks | 3 weeks to several months | |
| Functional Vision Recovery | 3 to 7 days | 24 hours | 3 to 7 days | |
| Visual Results Fully Recognized | 3 weeks to several months | 1 to 6 weeks | 3 weeks to several months | |
| Return to Work | 2 to 3 days | 1 to 2 days | 2 to 3 days | |
| Risk of Complications | Low | Low | Low | |
| Risk of Scarring | 1 to 2% | <1% | Possibly less than PRK | |
| Dry Eye Sensitive | 1 to 4 weeks | Could last up to 12 months or more | 1 to 4 weeks | |
| Candidates with Thin Corneas or Wide Pupils | Often good candidates | Candidacy depends on amount of correction needed | Often good candidates | |
