Comparison of LASIK and Surface Ablation by Using Propensity Score Analysis: A Multicenter Study in Korea
ABSTRACT Purpose. We compared the 3-year outcomes with regard to efficacy, stability, and safety of LASIK and surface ablation performed at multiple centers in Korea. Methods. The charts of 5109 eyes that underwent LASIK or surface ablation, including LASEK, epi-LASIK, and photorefractive keratectomy (PRK), at multiple centers between 2002 and 2005 were reviewed. Of these, 577 LASIK-treated eyes and 577 propensity score-matched surface-ablated eyes were included in this cohort study. A standardized case report form (CRF) was completed based on a review of the 3-year follow-up chart. The CRF included the preoperative, surgical, and postoperative data for the refractive error, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), IOP, corneal thickness, keratometry, corneal topography, Schirmer test, and tear breakup time (TBUT). Results. The efficacy index calculated after 3 years and the postoperative spherical equivalents measured at 3 months or 3 years did not differ between the LASIK and surface ablation groups. Although myopic regression was observed in the surface ablation group through postoperative years 1 and 2, this difference did not affect the visual acuity significantly. Surface ablation did carry a higher cumulative incidence of corneal haze. Conclusions. LASIK and surface ablation produced similar postoperative visual efficacy after corneal healing. The outcome predictability did not differ between the 2 groups, but myopic regression was observed more frequently in the surface ablation group. Corneal haze after surface ablation is much more common than reported previously.
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ABSTRACT: To evaluate a new curvature gradient topography map to predict postoperative corneal remodeling. In this retrospective study, 32 eyes of 16 patients with myopia underwent excimer ablation surgery with a postoperative high curvature gradient. The new curvature gradient map (acquired immediately postoperatively) shows the difference between the curvatures of two points over the distance between them; it was compared to the tangential curvature difference map between 1 and 12 months postoperatively to determine their relationship. Corneas were divided into 12 regions for analysis: four 90°-wide sectors centered on 0°, 90°, 180°, and 270°. There were three subdivisions in each sector: central (radius: 0 to 2.75 mm), paracentral (radius: 2.75 to 3.25 mm), and peripheral (radius: 3.25 to 4.5 mm). Linear regression analysis was performed by region. The following regions had significant relationships between the initial curvature gradient and curvature difference between 1 and 12 months postoperatively: the paracentral zone of the 90° sector (P = .0145; R(2) = 0.1832) and both the central (P = .0034; R(2) = 0.2522) and paracentral (P = .0452; R(2) = 0.1271) zones of the 270° sector. The greatest average initial tangential curvature was in the 270° sector. The initial curvature gradient after surgery predicted change in tangential curvature over the subsequent 12 months in areas where initial tangential curvature was greatest. When the curvature gradient was high, the surface curvature modification remained in progress months after surgery. [J Refract Surg. 2014;30(3):202-207.].Journal of refractive surgery (Thorofare, N.J.: 1995) 03/2014; 30(3):202-7. DOI:10.3928/1081597X-20140218-02 · 2.78 Impact Factor
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ABSTRACT: Dry eye is the most common post-operative complication in patients who undergo laser-assisted in situ keratomileusis and other photorefractive procedures. Epidemiological studies have found that almost all patients experience some form of dry-eye-related discomfort in the post-operative period. This review seeks primarily to identify patient factors, which predispose to this complication, as well as outline the possible interventions clinicians can consider to avoid, prevent and treat this complication. Numerous pre-, intra- and post-operative guidelines are provided. The ideal method of post-laser-assisted in situ keratomileusis dry eye prevention is a meticulous peri-operative management plan, as opposed to post-operative management alone. Newer modalities of photorefractive surgery may have differing effects on the ocular surface.Expert Review of Ophthalmology 01/2014; 8(6). DOI:10.1586/17469899.2013.851602