Aspheric Ablation Depth as the Target Depth for Enhanced Wavefront-Guided Myopic Retreatments After Laser-Assisted In Situ Keratomileusis.

Abstract

PURPOSE:

To propose a new adjustment method and present the clinical result of wavefront-guided myopic laser-assisted in situ keratomileusis (LASIK) retreatment with an aspheric program-targeted central ablation depth to avoid refractive overcorrection.

METHODS:

Thirty-two eyes (of 20 consecutive patients) that underwent wavefront-guided LASIK myopic retreatment between January 2009 and February 2012 after primary wavefront-guided LASIK for myopia were included. Wavefront-guided retreatments were performed using the Bausch and Lomb Technolas 217z100 excimer laser system. Wavefront-guided retreatments were adjusted by setting the ablation depth corresponding to the ablation depth determined by the aspheric program. The refractive outcome, visual outcome, and outcome of high-order aberrations (HOAs) were analyzed. Linear mixed models were also used to evaluate the predicting factors for retreatment offset.

RESULTS:

Mean age was 29.5 ± 3.1 years. Spherical equivalent (SE) before retreatment was -1.0 ± 0.44 diopters (D) (range, -2.25 to -0.5). Twelve months postoperatively, SE was -0.03 ± 0.12 D, and 31 of 32 eyes had an uncorrected visual acuity 20/20 or better. All eyes were within ±0.5 D. None of the eyes had lost >2 lines of Snellen visual acuity. Safety and efficacy indices were 1.03 and 1.00, respectively. Total HOA, coma, and trefoil were reduced significantly (P = 0.028, P = 0.036, P = 0.034, respectively). Predictive factors for the amount of offset required are significantly related to preoperative SE (P = 0.006) and spherical aberration (P = 0.03, adjusted by SE).

CONCLUSIONS:

Setting the target ablation depth using the aspheric program provided high refractive predictability with a satisfactory visual outcome, significant reduction of HOAs, and no overcorrections.

• Authors: Yung-Ray Hsu, Elizabeth P Shen, Yi-Ting Hsieh, Huai-Wen Chang, Fung-Rong Hu
• Journal: Cornea (Cornea) Vol. 34 Issue 12 Pg. 1577-81 (Dec 2015) ISSN: 1536-4798 [Electronic] United States
• PMID: 26488625 (Publication Type: Journal Article)

Topics

• Adult
• Corneal Stroma (surgery)
• Corneal Wavefront Aberration (surgery)
• Female
• Humans
• Keratomileusis, Laser In Situ (methods)
• Lasers, Excimer (therapeutic use)
• Male
• Myopia (physiopathology, surgery)
• Refraction, Ocular (physiology)
• Reoperation
• Visual Acuity (physiology)