Efficacy and safety of photorefractive keratectomy (PRK) for myopia using a new blunt combined, chemical and mechanical, corneal epithelium debridement technique

Session Details

Session Title: Surface Ablations for Correction of Ammetropias

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 09:06

Venue: Auditorium

First Author: : R.Bilbao-Calabuig SPAIN

Co Author(s): :    F. Gonzalez-Lopez   J. Villada-Casaponsa   J. Beltran        

Abstract Details

Purpose:

To evaluate the clinical outcomes of PRK for myopia, using a new corneal epithelium peeling technique.

Setting:

Clinica Baviera Madrid. Spain.Private Ophthalmic Clinic

Methods:

This retrospective consecutive interventional cases series study comprised patients who had PRK to correct myopia or myopic astigmatism performed by one single surgeon R B-C since april 2011. To debride corneal epithelium, a circular 8 mm wickcell sponge with 20% ethanol solution was positioned over the central cornea for 50 seconds. Epithelial adhesions were then released with another wickcell spear, and finally, central loosened corneal epithelium was easily lifted off with the same wickcell spear in a circular epitheliorexis manner. Corneal photoablation was then performed using a Technolas 217 Z laser platform, using our usual nomograms and algorithms for myopic treatments. Following laser ablation, 0.02% MMC was applied on the ablated stroma. The duration of MMC application was 12 seconds when the depth of central ablation was less than 65 microns and 20 seconds if more than 65 microns. Manifest refraction, uncorrected distance visual acuity (UDVA), and corrected distance visual cuity (CDVA) were assessed preoperatively and postoperatively.

Results:

This study evaluated 248 eyes of 144 patients ( 80 women and 64 men). Mean preoperative manifest refraction spherical equivalent (MRSE) was -3.73D±1.49 SD (Range -7.12 to -1 D) and mean preoperative cylinder -0,65 D±0,71 SD (Range 0 to -4D). After 3 months ( mean 120± 58 days), mean UCDVA was 0.97±0.08 and MRSE was -0.04±0.33 (range +0.85 to -0,82); postoperatively 96% of eyes had a MRSE within ± 0.5D of emmetropia. The Efficay Index was 0.99 and the Safety Index 1.02. Postoperative mean time for complete reepithelization and contact lens removal was 5.1±0.4 days, and no patient required more than 14 days of contact lens wear. No eye lost two or more lines of CDVA or presented any significant clinical complication . Only one eye required an enhancement procedure at the end of follow-up.

Conclusions:

This new corneal epithelium debridement technique has allowed us to optimize our results when correcting myopia with surface ablation photorefractive surgery. The technique that combines a chemical and a mechanical action, reduces patient discomfort, obviates the spilling of toxic or irritating solutions over the ocular surface, avoids the application of pressure over the ocular globe and spares the use of sharp instruments during the surgery. These factors could minimize intraoperative corneal damage, reducing thus postoperative inflammation, and subsequently could improve our surgical performance.

Financial Interest:

NONE