ABSTRACT
PURPOSE: To identify the laser programming strategy that will achieve optimal refractive outcomes of LASIK with a topography-guided laser for eyes with a disparity between cylinder measured by manifest refraction and cylinder measured by topography. SETTING: Six surgeons at 5 clinical sites in the USA. DESIGN: Retrospective data review. METHODS: Preoperative, treatment, and postoperative data on 52 eyes that underwent topography-guided LASIK with the WaveLight EX500 Contoura® Vision excimer laser ablation profile in which the vectors representing the preoperative refractive cylinder and the cylinder measured by the WaveLight® Topolyzer™ VARIO Diagnostic Device (Vario cylinder) differed by >/= 0.50D and/or >/= 10 degrees of orientation were analyzed retrospectively. Data were contributed by six surgeons using the laser at 5 different clinical sites. Vector analysis of postoperative cylindrical refractive error and the actual laser programming strategy was used to calculate the cylindrical correction that would, theoretically, have completely eliminated postoperative refractive cylinder. This was compared to expected results using the preoperative manifest cylinder, the topographic cylinder, and the Phorcides Analytic Engine (Phorcides LLC, North Oaks MN; Phorcides). For analysis, subjects were stratified on the basis of the vector difference between Manifest and Topo cylinder (High, >0.75 D; and Low, ≤0.75 D). RESULTS: The poorest calculated theoretical outcomes were obtained with the manifest refraction (centroid: -0.43, 0.22; mean calculated error vector: 0.56 ± 0.42 D; p=ns). Better outcomes were obtained with the topographically measured refraction (centroid: 0.37, 0.02; mean calculated error vector: 0.47 ± 0.33 D; p=ns). The best outcomes were obtained with Phorcides (centroid: -0.15, 0.06; mean calculated error vector: 0.39 ± 0.28 D; p=ns). The mean error vector magnitude in the Phorcides Low group was significantly lower than for the Manifest and Topo Low groups (0.26 D vs 0.48 D and 0.33 D; p<0.01). The mean error magnitude in the Phorcides High group was nearly 0.25 D lower than for the Manifest High group (0.48 D vs 0.70 D; p<0.01), but was the same as for the Topo High group (0.48 D vs 0.48 D). CONCLUSION: Our study suggests that using the topographically measured cylinder or the cylinder selected by Phorcides will produce more desirable refractive outcomes than entry of the preoperative refractive cylinder as the basis for correction of myopia and myopic astigmatism with the WaveLight Contoura Vision excimer laser.
ABSTRACT
PURPOSE: To assess longitudinal refractive, keratometric, and topographic changes following KAMRA small-aperture inlay implantation. DESIGN AND SETTING: Prospective study at a single site refractive surgery center. METHODS: Fifty patients underwent KAMRA small-aperture corneal inlay implantation for the correction of presbyopia. Uncorrected near visual acuity (UNVA), uncorrected distance visual acuity, manifest refractive spherical equivalent (MRSE), mean keratometry (Km), corneal topography, and surgically induced astigmatism vector analysis assessments were performed preoperatively and at 1, 3, 6, 12, 24, and 36 months postoperatively. RESULTS: The study comprises 50 eyes. An average shift of 0.15±0.63 D (range -1.63 to 2.00 D) occurred between preoperative baseline and 36 months. At 36 months, 54% of patients had hyperopic MRSE and 40% had myopic MRSE compared with baseline. Km was significantly elevated at all postoperative measurements compared with baseline, with the largest Km measured at 12 months. Eighty-six percent of patients had UNVA of 20/32 or better and 88% uncorrected distance visual acuity of 20/25 or better at 36 months. Longitudinal corneal topography revealed a pattern of corneal steepening over the body of the inlay and flattening over the aperture, correlating with a hyperopic shift. There was no significant surgically induced astigmatism. CONCLUSION: KAMRA inlay may cause an increase in Km compared with baseline. Corneal steepening may occur in a specific pattern with steepening over the inlay and flattening over the aperture. This topographic pattern causes a hyperopic shift, which may be relevant for subsequent procedures, such as cataract extraction.
ABSTRACT
PURPOSE: To analyze the impact of the three latest U.S. Food and Drug Administration (FDA)-approved lasers on patient-reported outcomes after LASIK. METHODS: In this meta-analysis of patient-reported FDA data, an aggregated total of 718 eyes undergoing LASIK using VISX iDesign (Abbott Medical Optics Manufacturing, Milpitas, CA), Alcon Contoura (Alcon Research, Ltd., Fort Worth, TX), and Nidek CATz (Nidek Co. Ltd., Gamagori, Japan) lasers were evaluated for overall changes in visual symptoms postoperatively. Statistical significance was calculated when appropriate to assess changes. A P value of less than .05 was considered statistically significant. RESULTS: At 12 months following LASIK, there was a decrease in the postoperative difficulty driving at night (29%) with respect to preoperative values. There was a significant postoperative reduction in prior moderate to severe symptoms for light sensitivity (9%), difficulty driving at night (22%), reading difficulty (8%), double vision (2%), glare (12%), and halos (6%) at 12 months following LASIK. CONCLUSIONS: Analysis of the FDA data shows that modern lasers have significantly improved patient-reported visual outcomes after LASIK. [J Refract Surg. 2017;33(6):362-368.].
