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Clinical results of photorefractive keratectomy with optimized prolate ablation in patients with myopia greater than 8 diopters

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Session Details

Session Title: Presented Poster Session 02: Keratorefractive Surgery Outcomes - Myopia 1

Session Date/Time: Saturday 13/09/2014 | 09:30-11:00

Paper Time: 10:00

Venue: Pod 2 (Poster Village)

First Author: : B.Choi SOUTH KOREA

Co Author(s): :    D. Kim              

Abstract Details


To evaluate the clinical outcomes of photorefractive keratectomy (PRK) with Optimized Prolate Ablation (OPA) algorithm for the treatment of myopia greater than 8 diopters.


Private practice, Busan, South Korea.


This retrospective study included 50 eyes of 32 patients with myopia greater than 8 diopters who had PRK with OPA algorithm using a NIDEK excimer laser. The mean manifest refraction spherical equivalent(MRSE) was -8.84 diopters(-8.12~-11.0 D) and the mean central ablation depth was 130.5㎛. The mean optical zone and transitional zone size were 5.8 and 7.4 mm respectively. Phototherapeutic Keratectomy (PTK) smoothing(mean 19.4㎛) and mitomycin C application (mean 29 seconds) were used to prevent corneal haze. The OPDScan Ⅲ (NIDEK Co., Ltd., Gamagori, Japan) was used to evaluate the topographic and wavefront data. We got the shot data that the simulated postoperative spherical aberrations were targeted to zero using OPA algorithm. Visual acuity, MRSE, spherical aberrations, corneal asphericity (Q value), and point spread function (PSF) were measured 1, 3, and 6 months postoperatively.


Six months after surgery, the mean MRSE was -0.26 diopters and the mean Snellen uncorrected distance visual acuity (UDVA) in decimal equivalent was 1.1 and all patients had UDVA of 0.8 or better. The mean ocular spherical aberration was 0.08 preoperatively and increased to 0.19 six months after surgery. The mean corneal spherical aberration was 0.27 preoperatively and increased to 0.53 six months after surgery. The mean PSF (Strehl ratio) was 0.066 preoperatively and decreased to 0.027. The mean Q value was -0.16 preoperatively and +0.65 after surgery. Only three eyes had a corneal opacity greater than Grade 1.


PRK with OPA in patients with myopia greater than 8 diopters is a safe and effective treatment option. We could get good visual acuity and stable refraction for 6 months. Visual quality may be good because increased spherical aberration was not much after surgery.

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