Is Photorefractive Keratectomy the Laser Vision Correction of Choice? Dr. JoAnn Chang Dr. Mark Mifflin Dr. Majid Moshirfar The authors have no financial interest in the content of this presentation.

Purpose To report the increasing utilization of PRK by multiple refractive surgeons at a single academic institution

Methods A retrospective case review of 6675 refractive surgeries at the John A. Moran Eye Center from January 1, 2002 to July 31, 2008 was performed. The change in proportion of PRK to LASIK cases over time was analyzed.

Methods Analysis of 2008 PRK patients (n=166) Manifest refraction spherical equivalent (MRSE) Pachymetry at the thinnest location (CCT) Topographic symmetry patterns Reasons for PRK

Results Excluding all other refractive procedures, 5836 cases were either PRK or LASIK. Rate of PRK per year, as a percentage of LASIK volume 2002 – 8% 2003 – 9% 2004 – 17% 2005 – 25% 2006 – 45% 2007 – 54% 2008 – 115% *PRK exceeded LASIK in the first half of 2008

Results Graphically, the increasing % PRK is seen below

Results PRK patients (Jan – Jul 2008, n=166) Average age 36 years (20 to 62) Mean MRSE -4.59 D (+1.75 to -10.00) Average CCT 530 µm (425 to 650) Custom wavefront treatment was performed in 56% of patients.

Results – 2008 PRK Patients Reasons for choice of PRK over LASIK Topographic Thin CCT Asymmetry Step curvature Surface Disease Dry eye Syndrome Other (ABMD, scar) Surgeon recommendation Patient preference

Results Separate analysis comparing the preoperative and postoperative data from a sampling of 385 LASIK and 402 PRK eyes (2008) was also performed Table 1: Comparison of preoperative data from sampling of PRK and LASIK patients PRK (n = 402) LASIK (n = 385) Age (years) 35 ± 10 36 ± 10 Sphere (D) -4.38 ± 2.1 -3.89 ± 2.2 Cylinder (D) 0.83 ± 0.90 0.92 ± 0.90 CCT (µm) 535 ± 38 558 ± 34 PRK = photorefractive keratectomy; D = diopters; LASIK = laser-assisted in situ keratomileusis; CCT = central cornea thickness

Results The outcomes between LASIK and PRK patients are similar as seen here at 12 months.

Conclusion Photorefractive Keratectomy has steadily increased in frequency in our academic center, surpassing LASIK in 2008. Advances in laser technology, improved techniques for surface ablation and patient management, and safety considerations have resulted in increased acceptance of PRK by surgeons and patients in our practice.