PRK – Photo Refractive Keratectomy in Correction of Myopia: How Useful Is It?

Abstract

ABSTRACT:The study comprised of retrospective and prospective evaluation of 30 eyes treated with PRK -Photo Refractive Keratectomy at Mahatme Eye Bank Eye Hospital, Nagpur India. Our results show that PRK is less safe, less effective and less predictable procedure in correcting high and extreme myopia and myopic astigmatism. KEYWORDS: Myopia, refractive surgery, Photo Refractive Keratectomy -PRK, keratome, hansatome, spherical equivalent (SE) refraction, BSCVA (Best surgically corrected visual acuity), UCVA (Uncorrected visual acuity), corneal haze, astigmatism. INTRODUCTION:PRK stands for Photo Refractive Keratectomy. PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. First PRK procedure was performed in 1987 by Dr. Theo Seiler, 1 then at the Free University Medical Center in Berlin, Germany. The main difference between PRK and LASIK is that in LASIK surgery a thin, hinged flap is created on the cornea to access the treatment area, whereas in PRK the cornea's entire epithelial (outer) layer is removed to expose the area and no flap is created. PRK is still commonly performed and offers advantages over LASIK for some patients.PRK advantages includes less depth of laser treatment than LASIK, suitable for patients with a thin cornea, no risk of corneal flap complications and reduced risk of compromised corneal thickness. The disadvantages of PRK are slower recovery than LASIK, best vision takes longer to obtain, increased risk of post-surgery infection, inflammation and haze and more eye discomfort during early PRK recovery, compared with recovery after LASIK surgery. 2 Unlike LASIK, in PRK corneal flap is not created. Instead, the outer layer of the cornea is removed to expose an area for a laser to reshape. This makes PRK a better choice for people whose eyes meet certain criteria, such as having thin corneas or chronically dry eyes. The most significant differences between PRK and LASIK are the initial discomfort and the speed of visual recovery. Recovery from PRK takes a little longer than from LASIK because the outer layer of the cornea needs time to heal.The present study aimed at finding out efficacy, safety, predictability and visual outcome of PRK in high myopia.