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Lasek Eye Sugery in San Diego
LASEK is a relatively new laser vision procedure that combines certain elements of both the PRK (Photo Refractive Keratectomy) and LASIK procedures and may offer some advantages for patients. Instead of removing the epithelium as with PRK, a flap of surface epithelium is loosened with a diluted alcohol solution and moved aside. The surface under the epithelium is treated with the laser and the epithelial flap is returned to its original position, as with LASIK. A protective, soft contact lens is then placed over the cornea to make the eye more comfortable while it heals.
Using the epithelium flap as a natural protective bandage with LASEK, as opposed to completely removing the epithelium as with PRK, may improve healing, reduce postoperative discomfort and the incidence of postoperative haze. And, the margin of safety with LASEK is increased over LASIK as the need for a microkeratome is eliminated.
The Visx Star S4 with Active Trak and Auto-centering is the most recent and state-of-the-art laser on the US market today, and can be used for both conventional and custom LASIK, PRK, and LASEK. The tracking device follows extremely small eye movements enabling the surgeons at Grendahl Eye associates to fine tune ablations done for PRK, LASIK and LASEK to achieve improved outcomes.
The Visx Star S4 Active Trak uses a video-based tracker composed of two infrared light sources and two cameras that establish a 3-D coordinate system on the eye, allowing it to track an eye in the z-axis ( in and out) as well as in the x- axis (left or right) and in the y-axis (up and down). The cameras are connected to the computer in the laser. When the eye moves to the right, left, up, down or in and out the computer directs the laser beam to move to the right, left, up, down or in and out by the same amount that the eye moved.
The Visx Star S4 Active Trak provides direct pupil measurement in real time. The laser shines the infrared light on the eye, and the computer performs a centroid calculation to find the center of the pupil. Even if the pupil changes size during the procedure due to varying lighting conditions this calculated pupil center won't change. It has a major advantage over other laser tracking systems because it dose not require the pupil to be dilated. Because the position of the pupil is measured directly by the infrared camera, this system is much more accurate.
Just centering the laser treatment on the pupil will not ensure that the treatment zone is centered after the laser surgery. Beam shape and placement on the cornea both will affect the outcome. The shape of the laser beam that reaches the corneal plane can differ significantly from the shape of the laser beam that leaves the laser if the eye is looking to far off the patient central fixation light. The beams angle relative to the corneal and iris plane is a key factor in centration of the treatment. All trackers track the iris plane and not the corneal surface, in order to center the laser beam over the pupil. When the patient does not fixate properly on the central fixation light in the laser, the eye drifts or moves off to one side. Under this condition the cornea moves a greater distance than the iris does (parallax). At this point, pupil centration is no longer accurate and the laser beam falling onto the cornea is ovalized (oval shaped) because of the increased angle.
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6950 Friars Road
Suite #100
San Diego, CA 92108
18632 Beach Blvd.
Suite #100
Huntington Beach,
CA 92648
800.GET-LASIK
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