Dr. Sandra Belmont is recognized by her peers as one of the leading experts in the development of PRK and LASIK.
“Laser vision correction was approved by the FDA as a safe and effective procedure in the mid-nineties. Back then, I was one of New York City’s principal investigators in the FDA studies that led to the approval for PRK and LASIK. Since then, more than 40 million people have been treated worldwide, and today laser vision correction is one of the most performed elective surgical procedures on the planet.”
~ Sandra Belmont, MD
Overview of LASIK and PRK
LASIK and PRK are the two most popular types of laser vision correction. Designed as one-time treatments to improve vision, laser vision correction greatly reduces or eliminates the need for glasses and contact lenses in patients who are nearsighted, farsighted, astigmatic or presbyopic. The key component in the process is the excimer laser, an incredibly precise computerized device that produces a blue beam of laser light that is cool to the touch and specifically tuned to reshape the collagen matrix of the cornea with great accuracy. The cornea is the clear, outermost part of the eye that is largely responsible for our ability to focus at distance.
Definition of LASIK
LASIK, an acronym for laser-assisted in situ keratomileusis, was for many years the procedure of choice as it was able to treat most patients. LASIK differs from PRK mainly because in a LASIK procedure, a microkeratome or a femtosecond laser is used as a first step, to make a tiny hinged flap at a depth of about one-fifth of the cornea’s thickness in order to access the stromal bed below, the layer of the cornea that is below the skin layer. The stroma is then reshaped by the same excimer laser that is used for PRK. After the laser has finished reshaping the stroma, the hinged surface flap is put back as a cover, where it remains fixed in place by the eye’s own hydrostatic pressure. LASIK’s popularity for the better part of a decade was due to the fact that it allowed for the treatment of most types of refractive errors, including nearsightedness, farsightedness, astigmatism and presbyopia. As LASIK requires cutting the cornea in order to make a flap, patients at risk for dry eye were forewarned about the need for lubricating drops for some time post-operatively, until the cornea is once again enervated. Patients with corneas that were a bit on the thin side were also ruled out as viable candidates for LASIK.
Definition of PRK
PRK, an acronym for photorefractive keratectomy, is an outpatient surgical procedure that uses the excimer laser to painlessly change the shape of the cornea (the clear, outermost part of the eye). The laser sculpts the cornea very precisely so that light entering the eye will come into sharp focus on the retina (in the back of the eye), eliminating the need for corrective glasses or contact lenses.
A predecessor to LASIK, PRK was first approved by the FDA for the treatment of low to moderate degrees of nearsightedness in December of 1995. In a PRK procedure, the outermost surface cells of the cornea are removed, after which an excimer laser is used to permanently reshape the stromal layer of the cornea and correct for nearsightedness. This circumvents the need for doing any cutting at all and provides PRK with a superior safety profile to LASIK. The surface cells on the cornea grow back very quickly, in just a few days, and the patient is unburdened of his or her need for corrective glasses or contacts. The initial limitations of PRK as a procedure for nominally to moderately nearsighted individuals led to the development of LASIK as an alternative to address most other refractive errors, including: high degrees of nearsightedness, farsightedness, astigmatism and presbyopia. As a consequence, PRK was replaced by LASIK for some time, as the procedure of choice. In the ensuing years, PRK has evolved and now ADVANCED PRK (also referred to as ASA, or Advanced Surface Ablation) can treat most refractive errors. The fact that PRK is a no-cut procedure makes it very patient friendly and PRK also circumvents most other shortcomings in a LASIK procedure. At present, many surgeons are routinely performing Advanced PRK and forgoing the older LASIK procedures in favor of PRK.
Do you qualify for laser vision correction?
PRK, LASIK and all other variants of laser vision correction are FDA approved for the treatment of nearsightedness, farsightedness, astigmatism and presbyopia for those patients that wish to be unburdened of a dependence on glasses and contact lenses. A comprehensive, thorough examination is affected during your consultation, the first visit for laser vision correction, to ensure that you are a good candidate. The exam rules out anything that may disqualify you from benefiting from laser vision correction. Some conditions that may disqualify a patient include but are not limited to: a visually significant cataract; unusually thin or unusually shaped corneas; and retinal conditions that hinder one’s visual acuity and are not correctable with glasses or contacts. Once all of these have been ruled out, the diagnosis can be limited to either nearsightedness, farsightedness, astigmatism or presbyopia. These manifest as a consequence of the shape of the eye, where the eye is too long or too short (nearsightedness and farsightedness, respectively), or where the cornea is shaped more like a football than a baseball (as is the case for astigmatism). Presbyopia, the age related inability to focus on near objects that develops as we reach our fifties, can also be addressed with laser vision correction. Dr. Belmont will discuss the LASIK or PRK procedure that is best suited to each patient and explain in detail what to expect during and immediately following the treatment as the patients heal post-operatively. There is no sensation in the course of undergoing a LASIK or PRK procedure and most patients are able to return to work and driving in a matter of days.