Transepithelial Prk (Smartsurface) Procedures Guided By Corneal Epithelial Profile For Correction Of Post Lasik Myopic Regression

Post LASIK myopic regression occasionally occurs. Common way of treating regression is enhancement by flap relift. But, if flap was created years ago, there is an increased risc of intraoperative or postoperative complication, like epithelial ingrowth. Other option is to perform transepithelial PRK (transPRK) over the LASIK flap. But disadvantage of that approach could be lower refractive predictability of surface ablation over the LASIK flap, possibly due to modified post LASIK corneal epithelial profile. The goal of this paper is to present results of SmartsurfACE transPRK for treatment of post LASIK myopic regression, in which epithelial component of photoablation was determined on case by case basis by OCT epithelial mapping.

 

Private Eye Clinic “Profesional“, Belgrade, Serbia

 

We treated 13 eyes of 10 patients by Schwind SmartsurfACE transPRK. In 8 eyes aberration free profile was used, and in 5 corneal wavefront guided profile. Procedures were done 6,2 years after primary LASIK procedure (range 2 to 11). Preoperative spherical equivalent (SE) was -1.42±0.39 (-2.0 to -0.75), and manifest astigmatism -0.23±0.28 (-0.75 to 0). Pre op uncorrected distance visual acuity (UDVA) was 0.47±0.08 (logMAR) (0.7 to 0.3), corrected to (DCVA) 0.06±0.08 (0.2 to 0.0). Pre op minimal epithelial thickness was 46.23 microns (41 to 51), and maximal 64.23 (57 to 79).Mean optical zone used was 7.14 mm (6.5 to 7.5).Mean central epithelial component of transPRK ablation was 61.0 microns (55 to 75),and peripheral 65.7 (60 to 75).

 

Six months post op SE was -0.08±0.19 (-0.38 to 0.25) and manifest astigmatism -0.22±0.18 (-0.50 to 0). Post op UDVA was 0.03±0.05 (0.1 to 0.0). 100% was within ±0.50 D of SE and within ±0.50 D of manifest astigmatism. Regarding efficacy, 100% of eyes had post op UDVA equal or better compared to pre op CDVA. Regarding safety, no eyes lost lines of CDVA, while 40% of eyes gained one line of CDVA. Mean post op minimal epithelial thickness was 49.2 microns (47 to 51 ), and maximal 58.9 (55 to 62 ). There were no postoperative complications. 

 

SmartsurfACE TransPRK procedures, guided by corneal epithelial profile, were in our experience safe, predictable and successful in treatment of late post LASIK myopic regression. Beside good refractive and visual outcomes, significant postoperative corneal epithelial regularisation was observed.