Dataset Information

Comparison of simulated keratometric changes following wavefront-guided and wavefront-optimized myopic laser-assisted in situ keratomileusis.

ABSTRACT: Purpose:The aim of the study was to determine and compare the relationship between change in simulated keratometry (K) and degree of refractive correction in wavefront-guided (WFG) and wavefront-optimized (WFO) myopic laser-assisted in situ keratomileusis (LASIK). Methods:A total of 51 patients were prospectively randomized to WFG LASIK in one eye and WFO LASIK in the contralateral eye at the Byers Eye Institute, Stanford University. Changes in simulated K and refractive error were determined at 1 year post-operatively. Linear regression was employed to calculate the slope of change in simulated K (?K) for change in refractive error (?SE). The mean ratio (?K/?SE) was also calculated. Results:The ratio of ?K to ?SE was larger for WFG LASIK compared to WFO LASIK when comparing the slope (?K/?SE) as determined by linear regression (0.85 vs 0.83, p = 0.04). Upon comparing the mean ratio (?K/?SE), subgroup analysis revealed that ?K/?SE was larger for WFG LASIK for refractive corrections of >3.00 D and >4.00 D (0.89 vs 0.83; p = 0.0323 and 0.88 vs 0.83; p = 0.0466, respectively). Both linear regression and direct comparison of the mean ratio (?K/?SE) for refractive corrections <4.00 D and >4.00 D revealed no difference in ?K/?SE between smaller and larger refractive corrections. Conclusion:WFO LASIK requires a smaller amount of corneal flattening compared to WFG LASIK for a given degree of refractive correction. For both, there was no significant difference in change in corneal curvature for a given degree of refractive error between smaller and larger corrections.

SUBMITTER: Lee WS

PROVIDER: S-EPMC5880184 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Comparison of simulated keratometric changes following wavefront-guided and wavefront-optimized myopic laser-assisted in situ keratomileusis.

Lee Wen-Shin WS Manche Edward E EE

Clinical ophthalmology (Auckland, N.Z.) 20180329

<h4>Purpose</h4>The aim of the study was to determine and compare the relationship between change in simulated keratometry (K) and degree of refractive correction in wavefront-guided (WFG) and wavefront-optimized (WFO) myopic laser-assisted in situ keratomileusis (LASIK).<h4>Methods</h4>A total of 51 patients were prospectively randomized to WFG LASIK in one eye and WFO LASIK in the contralateral eye at the Byers Eye Institute, Stanford University. Changes in simulated K and refractive error wer ...[more]

PMID: 29636597

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Project description:BackgroundCorneal refractive surgery for myopia results in an oblate shift with increased postoperative aberrations inversely affecting the quality of vision. Aspheric ablation profiles have been introduced to minimize such a problem. The aim of this study was to compare changes in corneal asphericity, central and mid-peripheral pachymetry between the Q-value customized and the wavefront-optimized (WFO) ablation profiles.MethodsA prospective, comparative non-randomized fellow eye study was conducted. Eighty eyes of 40 eligible patients underwent femtosecond laser-assisted laser in situ keratomileusis for myopia and myopic astigmatism. In each patient, the more myopic eye was included in the custom-Q ablation experimental group and the other less myopic eye was included in the WFO control group. For the custom-Q group, the target asphericity was set to the preoperative Q-value. Corneal asphericity, central and mid-peripheral pachymetric changes and the root mean square of corneal higher-order aberrations (RMSh) were assessed 6 months following surgery. Visual and refractive outcomes were also evaluated in both platforms 6 months postoperatively.ResultsThe mean preoperative refractive spherical equivalent was significantly more myopic in the custom-Q group than in the WFO group (P = 0.001). The mean Q-value changed from - 0.2 ± 0.1 to 0.6 ± 0.7 and from - 0.2 ± 0.1 to 0.4 ± 0.5 in the custom-Q and WFO groups, respectively. The oblate shift in corneal asphericity was not significantly different between both treatment groups (P = 0.094). The mean ablation depth at the pupillary center was significantly greater in the custom-Q group (P = 0.011), while there was no significant difference at the mid-peripheral pachymetry (P = 0.256). The RMSh significantly increased in both treatment profiles (P < 0.001) with no significant difference between the two groups (P = 0.06). The uncorrected distance visual acuity (UDVA) and the manifest refraction spherical equivalents (MRSE) significantly improved in both treatment groups (P < 0.001).ConclusionsThe custom-Q treatment profile with target asphericity set at the preoperative Q-value achieved comparable outcomes vs. the WFO profile in terms of postoperative corneal asphericity and mid-peripheral pachymetry despite the greater amount of ablation, the smaller optical zone, and the resulting increase in postoperative corneal flattening in the custom-Q group. Trial registration (Clinicaltrials.gov): NCT04738903, 4 February 2021- Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04738903.

Project description:BACKGROUND:Hyperopia, or hypermetropia (also known as long-sightedness or far-sightedness), is the condition where the unaccommodating eye brings parallel light to a focus behind the retina instead of on it. Hyperopia can be corrected with both non-surgical and surgical methods, among them photorefractive keratectomy (PRK) and laser assisted In situ keratomileusis (LASIK). There is uncertainty as to whether hyperopic-PRK or hyperopic-LASIK is the better method. OBJECTIVES:The objectives of this review were to determine whether PRK or LASIK leads to more reliable, stable and safe results when correcting a hyperopic refractive error. SEARCH METHODS:We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 2), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to February 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 17 February 2012. When trials are included in the review we will search the reference lists of the studies included in the review for information about further trials. We will use the Science Citation Index to search for papers that cite any studies included in this review. We did not handsearch journals or conference proceedings specifically for this review. SELECTION CRITERIA:We planned to include only randomised controlled trials (RCTs) comparing PRK against LASIK for correction of hyperopia and then perform a sensitivity analysis of pre- and post-millennial trials since this is the mid-point in the history of both PRK and LASIK. DATA COLLECTION AND ANALYSIS:We did not identify any studies that met the inclusion criteria for this review. MAIN RESULTS:As no studies met the inclusion criteria for this review, we discussed the results of non-randomised trials comparing hyperopic-PRK with hyperopic-LASIK. AUTHORS' CONCLUSIONS:No robust, reliable conclusions could be reached, but the non-randomised trials reviewed appear to be in agreement that hyperopic-PRK and hyperopic-LASIK are of comparable efficacy. High quality, well-planned open RCTs are needed in order to obtain a robust clinical evidence base.

Dataset Information

Comparison of simulated keratometric changes following wavefront-guided and wavefront-optimized myopic laser-assisted in situ keratomileusis.

Publications

Comparison of simulated keratometric changes following wavefront-guided and wavefront-optimized myopic laser-assisted in situ keratomileusis.

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