Optimizing Plasma Formation and Minimizing Microcavitation to Enhance Clinical Outcomes in Keratorefractive Lenticule Extraction

Abstract

Purpose: To compare early postoperative visual outcomes and higher order aberrations (HOAs) between plasma and conventional keratorefractive lenticular extractions (P-KLEx and C-KLEx). Methods: In this retrospective case series, records of patients who underwent KLEx surgery using two protocols-C-KLEx (symmetric spot/track distance laser spacing, 100-nJ pulse energy, VisuMax 500; Carl Zeiss Meditec) or P-KLEx (asymmetric spot/track distance laser spacing, 85-nJ pulse energy, VisuMax 800; Carl Zeiss Meditec)-were reviewed. Both groups received an identical total energy dosage of 625 mJ/cm(2). Postoperative visual acuity and corneal higher order aberrations (HOAs) were analyzed at 1 day, 2 weeks, and 2 months. Results: Among 281 eyes, 136 and 145 were included in the C-KLEx and P-KLEx groups, respectively. At postoperative day 1, the mean uncorrected distance visual acuities (UDVAs) were 0.02 +/- 0.04 and 0.01 +/- 0.08 logarithm of the minimum angle of resolution (logMAR) in the C-KLEx and P-KLEx groups, respectively (P = .22); however, the P-KLEx group demonstrated significantly better mean UDVA at 2 weeks and 2 months postoperatively (both P < .05). At 2 weeks postoperatively, the mean UDVAs were -0.01 +/- 0.04 and -0.04 +/- 0.07 logMAR in the C-KLEx and P-KLEx groups, respectively, and at 2 months postoperatively, the mean UDVAs were -0.02 +/- 0.04 and -0.04 +/- 0.06 logMAR, respectively. The P-KLEx group showed less induction of total HOAs, coma, and spherical aberration than the C-KLEx group (all P < .05). Conclusions: P-KLEx, which minimizes microcavitation and creates a lenticule with near-pure plasma, shows more favorable outcomes than C-KLEx, yielding better early postoperative visual acuities and reduced induction of corneal HOAs.