نتایج جستجو برای: astigmatic axis

تعداد نتایج: 102624  

2008
Tobias Schmid Kevin Thompson Jannick Rolland

There is a long list of new ground-based optical telescopes being considered around the world. While many are conventional Cassegrain and Ritchey-Chretien designs, some are from a family of three mirror anastigmatic (TMA) telescopes that are configured with an offset field (but still obscured) that trace back to designs developed in the 1970s for military applications. The nodal theory of aberr...

2015
Sang-Yeob Kim Byeong-Yeon Moon Hyun Gug Cho

[Purpose] To assess the changes in falling risk depending on the induced axis direction of astigmatism using cylindrical lenses in a static posture. [Subjects and Methods] Twenty subjects (10 males, 10 females; mean age, 23.4 ± 2.70 years) fully corrected by subjective refraction participated. To induce myopic simple astigmatism conditions, cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.0...

Journal: :African Vision and Eye Health 2019

Journal: :Optometry and vision science : official publication of the American Academy of Optometry 2013
Miguel Faria-Ribeiro António Queirós Daniela Lopes-Ferreira Jorge Jorge José Manuel González-Méijome

PURPOSE To compare the patterns of relative peripheral astigmatic refraction (tangential and sagittal power errors) and eccentric eye length between progressing and stable young-adult myopes. METHODS Sixty-two right eyes of 62 white patients participated in the study, of which 30 were nonprogressing myopes (NP group) for the last 2 years and 32 were progressing myopes (P group). Groups were m...

Journal: :Vision Research 2003
Velma Dobson Joseph M Miller Erin M Harvey Kathleen M Mohan

Best-corrected acuity was measured for vertical and horizontal gratings and for recognition acuity optotypes (Lea Symbols) in a group of three- to five-year-old children with a high prevalence of astigmatism. Results showed meridional amblyopia (MA) among children with simple/compound myopic or mixed astigmatism, due to reduced acuity for horizontal gratings. Children with simple/compound hyper...

Journal: :Computer Optics 2021

We theoretically show that an astigmatic transformation of nth-order edge dislocation (a zero-intensity straight line) produces n optical elliptical vortices (spiral dislocations) with unit topological charge at the double focal distance from cylindrical lens, located on a line perpendicular to dislocation, points whose coordinates are roots Hermite polynomial. The orbital angular momentum is p...

2014
Toam Katz Andreas Frings Stephan J Linke Gisbert Richard Vasyl Druchkiv Johannes Steinberg

BACKGROUND This study examined the refractive and visual outcome of wavefront-optimized laser in situ keratomileusis (LASIK) in eyes with low myopia and compound myopic astigmatism ≤ 0.75 diopter (D). METHODS 153 eyes from 153 consecutive myopic patients (74 male, 79 female; mean age at surgery 40.4 ± 10.4 years) who had a preoperative refractive cylinder ≤ 0.75 D and a manifest sphere betwee...

2017
Ashwag A Almosa Samah M Fawzy

Purpose. Long-term mitomycin C (MMC) effects on photorefractive keratectomy (PRK) were compared in simple myopic and astigmatic patients. Methods. In this observational cohort study, subjects were selected based on preoperative and postoperative data collected from medical records; they were divided into simple myopia with/without MMC and myopic astigmatism with/without MMC groups. Haze, uncorr...

Journal: :Journal of cataract and refractive surgery 2004
Konrad Pesudovs

PURPOSE To determine the limits of agreement between subjective refraction and autorefraction before and after laser in situ keratomileusis (LASIK) to assess whether autorefraction is a valid refractive outcome measure of refractive surgery. SETTING Ultralase, Leeds, United Kingdom. METHOD The prospective study involved consecutive preoperative normal patients and post-LASIK patients who ha...

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