Custom PRK surgery (photorefractive keratectomy) is a computer-assisted surgeon-controlled laser eye surgery that treats myopia (nearsightedness), hyperopia (far sightedness) and astigmatism by removing the surface layer of the cornea and reshaping the underlying tissue with excimer lasers The procedure is performed with the VISX Star S4 IR™ Laser System. PRK takes about 10 to 15 minutes per eye depending on the type and amount of correction required, and is performed on an outpatient basis at Horizon Laser Vision Center. The surgeon determines the amount of the treatment (vision correction) required with the help of iDesign® technology and programs the patient's unique corneal shape and refractive error into the computer prior to your procedure. Custom PRK surgery differs from LASIK in that a corneal flap is not created before the laser is used to treat the cornea - the cornea is sculpted rather than cut. The major benefit of this procedure is that the integrity and the strength of the cornea are retained. This allows the surgeon to make extremely accurate and specific modifications to the corneal surface to correct refractive errors.
Immediately preceding the procedure, numbing drops are placed in the eye and the area around the eye is cleansed. A small instrument called a lid speculum holds the eyelids open to prevent blinking and you will be asked to focus on a flashing fixation or target light in the laser.
Custom PRK surgery is performed in two main stages. During the first stage the surgeon looks through the laser's microscope and removes the very superficial tissue (epithelium) from the front of the cornea leaving an incredibly smooth undamaged tissue surface. The epithelium is removed with the Excimer laser, by use of an Amoil’s brush which scrubs the tissue off, or by use of an alcohol solution that loosens the tissue. This tissue regenerates and will grow back in a few days. Usually less than 50 microns (1mm = 1000 microns) of corneal tissue is removed. The surgeon will smooth the underlying surface and eliminate any moisture.
You will not experience any discomfort during this procedure, however you will notice your vision becomes more blurred. The surgeon will then be ready to treat the underlying tissue and modify your prescription.
While looking through the microscope, the surgeon will use the excimer laser to reshape the cornea by vaporizing an ultra-thin amount of the exposed corneal tissue.
Once the treatment is complete antibiotic and anti-inflammatory drops are placed in the eye and a bandage contact lens is inserted. The contact lens will protect the cornea and help the epithelium to heal more rapidly. The contact lens will also help decrease discomfort during the recovery period.