PRK (see also LASIK) PRK or Photo-Refractive Keratectomy treats refractive errors by removing tissue from the surface of the cornea. First, your eye is completely numbed using “eye drop” anesthesia and an instrument is placed between the eyelids to prevent blinking. Then, the surgeon removes the epithelium, a thin layer of protective skin that covers the cornea. The patient is told to look directly at a target light during the procedure. In less than a minute or two, the laser removes the proper amount of tissue while it reshapes the surface of the cornea. By altering the shape or placement of the laser beam, the cornea is made flatter to treat nearsightedness, steeper to treat farsightedness and/or more spherical to treat astigmatism.
PRK Vision Correction- What is nearsightedness?
In the normal eye, light bends through the cornea and lens to focus on the retina. With nearsightedness the eye is longer (or cornea is steeper) causing light to focus in front of the retina. The image is therefore out of focus on the retina and vision is blurred
Treating Nearsightedness using PKR Vision Correction
1. The corneal epithelium is removed in the treatment area.
2. Excimer laser is applied reshape (ablate) the cornea.
3. The corneal epithelium grows over the treated area.
4. The "flatter" cornea bends light to become focused on the retina.
What is Farsightedness?
In the normal eye, light bends through the cornea and lens to focus on the retina. With Farsightedness the eye is shorter (or cornea is flatter) causing the focal point of light to be behind the retina. The image is therefore out of focus on the retina and vision is blurred.
1. Excimer laser is applied to reshape (ablate) the cornea.
2. The "steeper" cornea now bends light to become focused on the retina.
Are You a Candidate for Laser Vision Correction?
In general, the ideal patient has a healthy cornea, and must not have had a significant increase in their prescription in the last year. People with certain medical conditions or pregnant women may not be good candidates.
The decision to have Laser Vision Correction is an important one that ultimately, only you can make. It is important that you have realistic expectations and that your decision is based on facts, not hopes or misconceptions. The goal of any refractive surgical procedure is to reduce your dependence on corrective lenses. Laser Vision Correction does not always create 20/20 or even 20/40 vision. It cannot correct a condition known as presbyopia, or aging of the eye, that normally occurs around age 40 and may require the use of reading glasses. In fact, people over 40 who have their nearsightedness reduced with surgery may find they need reading glasses after the procedure. Your doctor will provide you with additional information that will allow you to make an informed decision.
The First Step
Finding out more about the health of your eye and your refractive error is your first step towards visual independence. This is accomplished by calling your eye doctor and scheduling a personal consultation. Should your refractive error fall within the range of correction for Laser Vision Correction, more comprehensive tests will be necessary. This information will help you and your doctor determine which procedure is in your best interest.