Clinical outcomes of optimized prolate ablation and custom aspheric treatment in laser-assisted subepithelial keratectomy
Eui Chun Kang ; Bong Joon Choi ; Tae-im Kim ; Eung Kweon Kim
Journal of Cataract and Refractive Surgery, Vol.38(3) : 445~452, 2012
Journal of Cataract and Refractive Surgery
PURPOSE: To compare visual acuity, refractive, wavefront, and visual quality outcomes between optimized prolate ablation (OPA) and optical path difference custom aspheric treatment (OPDCAT) algorithms for myopia correction.
SETTING: Private practice, Busan, South Korea.
DESIGN: Prospective randomized masked clinical trial.
METHODS: One eye of each patient was randomly selected to have laser-assisted subepithelial keratectomy with the OPA algorithm and the contralateral eye with the OPDCAT algorithm. Visual acuity, manifest refraction, ocular and corneal higher-order aberrations (HOAs), corneal asphericity (Q value), and modulation transfer function (MTF) in the 2 groups were compared 1, 3, and 6 months postoperatively.
RESULTS: The study enrolled 39 patients. The mean manifest refraction spherical equivalent at 6 months was 0.19 diopter (D) ± 0.37 (SD) in the aspheric ablation group and 0.00 ± 0.33 D in the prolate ablation group. Predictability (± 0.50 D from intended refraction) at 6 months was 82% and 100%, respectively. Twenty-six eyes (93%) in the aspheric ablation group and 27 (96%) in the prolate ablation group had an uncorrected distance visual acuity of 20/20 or better. One eye in the aspheric ablation group and no eye in the prolate ablation group lost 1 line of corrected distance visual acuity. The prolate ablation group had fewer induced corneal and ocular spherical aberrations than the aspheric ablation group. Corneal asphericity was unchanged postoperatively in the prolate ablation group. The MTF under the correction of lower-order aberrations was higher in the prolate ablation group than in the aspheric ablation group.
CONCLUSION: The prolate ablation algorithm gave more predictable visual outcomes, induced fewer corneal HOAs, and conserved more preoperative corneal asphericity than the aspheric algorithm.
FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.