نتایج جستجو برای: corneal wavefront aberration
تعداد نتایج: 38950 فیلتر نتایج به سال:
purpose: to study the distribution of ocular higher-order aberrations (hoas) and mesopic pupil size in individuals screened for refractive surgery. methods: ocular hoas and mesopic pupil size were studied in 2458 eyes of 1240 patients with myopia, simple myopic astigmatism and compound myopic astigmatism and 215 eyes of 110 patients with hyperopia, simple hyperopic astigmatism and compound hype...
purpose: to evaluate the correlation between refractive, corneal and lenticular astigmatism and higher order aberrations (hoa) in refractive surgery candidates methods: this cross-sectional descriptive-analytical study consisted of 400 eyes (200 patients) who were referred between 2011 to 2013 to farabi eye hospital for refractive surgery. refraction, topography and aberrometry were performed t...
PURPOSE To determine whether Hartmann-Shack wavefront sensing detects differences in optical performance in vivo between poly(methyl methacrylate) (PMMA) and foldable acrylic intraocular lenses (IOLs) and between clear corneal and scleral tunnel incisions and whether optical differences are manifested as differences in visual performance. SETTING Department of Optometry, University of Bradfor...
The expansion of wavefront-sensing techniques redefined the meaning of refractive error in clinical ophthalmology. Clinical aberrometers provide detailed measurements of the eye's wavefront aberration. The distribution and contribution of each higher-order aberration to the overall wavefront aberration in the individual eye can now be accurately determined and predicted. Using corneal or ocular...
PURPOSE The aim of this analysis was to determine the total ocular wavefront aberration values of a large phakic population of physiologically normal, ametropic eyes, gathered under the same clinical protocol using the same diagnostic wavefront sensor. MATERIALS AND METHODS Studies were conducted at multiple sites in Asia, North America, Europe, and Australia. A Bausch + Lomb Zywave II Wavefr...
Both the anterior surface of the cornea and the internal optics (the posterior cornea, crystalline lens) contribute to the aberration of a wavefront passing through the eye. Artal, Guirao, Berrio, and Williams (2001) reported that the wavefront aberrations produced by the internal optics offset, or compensate for, the aberrations produced by the cornea to reduce ocular wavefront aberrations. We...
PURPOSE To assess the repeatability of corneal wavefront aberrations derived from Pentacam (Oculus) corneal topography. SETTING Flinders Eye Centre, Flinders Medical Centre, Bedford Park, South Australia, Australia. METHODS Forty-five normal participants and 10 participants with keratoconus were tested. Intraobserver and interobserver repeatability was determined using 4 observers within an...
PURPOSE To assess the compensation of total ocular and corneal wavefront aberrations after conventional myopic LASIK. METHODS This study comprised 57 eyes of 57 patients. Total and corneal aberrations were measured preoperatively and 3 months postoperatively using the OPD-Scan (NIDEK Co Ltd) aberrometer. Total and corneal aberrations root-mean-square (RMS) was calculated out to the 6th Zernik...
Purpose: The goal of this study was to investigate with what accuracy the Zernike and Fourier reconstruction algorithms can describe the corneal aberration in normal and abnormal eyes. Methods: Corneal topography (Orbscan IIz) was collected on 87 normal, 27 keratoconus, 9 penetrating keratoplasty (PKP), and 20 post-LASIK symptomatic eyes. Raw topography images were converted into elevation maps...
PURPOSE To assess the relationship between apparent accommodation in pseudophakic eyes, multifocal corneal effects, and wavefront aberrations of the cornea. METHODS In 102 eyes of 86 patients who had undergone phacoemulsification and posterior chamber intraocular lens implantation, the amount of apparent accommodation was measured with an accommodometer. The degree of corneal multifocality wa...
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