نتایج جستجو برای: coma aberration

تعداد نتایج: 16755  

1996
Florian Bociort

Florian Bociort Institute of Atomic Physics IPTRD-Department of Lasers P.O. Box MG-6 76900 Bucharest, Romania E-mail: [email protected] Abstract. Expressions for the Seidel aberrations of thin radial gradientindex (GRIN) lenses having a similar structure with the corresponding expressions for thin homogeneous lenses are obtained. By enabling a direct analysis of the relationship between aberration...

Journal: :European journal of ophthalmology 2017
Diego de Ortueta Sam Arba-Mosquera

PURPOSE To investigate refractive outcomes and induction of corneal higher order aberrations (HOA) in eyes that underwent laser-assisted in situ keratomileusis (LASIK) for high hyperopia correction using an aberration neutral profile with corneal vertex centration and asymmetric offset. METHODS A total of 24 consecutive patients (38 eyes) who underwent LASIK by one surgeon using AMARIS 750S e...

2015
Balamurali Vasudevan Brian Fisher Barry Case Phu Lam Jeff Wayman

BACKGROUND The aim of the present study was to investigate the effect of near-work on lower and higher-order aberrations, and its progression over a 9-month period during the school year. METHODS Data from 24 young-adult myopic eyes, and 24 non-myopic eyes were used in this investigation. The lower-order aberrations, coma, spherical aberration (SA), and total root mean square (RMS) of higher ...

2002
D. Lynden - Bell

A perfect focus telescope is one in which all rays parallel to the axis meet at a point and give equal magnification there. It is shown that these two conditions define the shapes of both primary and secondary mirrors. Apart from scale, the solution depends upon two parameters, s, which gives the mirror separation in terms of the effective focal length, and K, which gives the relative position ...

Journal: :Investigative ophthalmology & visual science 2008
Maria Clara Arbelaez Camila Vidal Samuel Arba-Mosquera

PURPOSE To compare the clinical outcomes of aberration-free ablation profiles based on the normal corneal vertex (CV) and the pupil center (PC) in relation to laser in situ keratomileusis. Aberration-free aspheric ablation treatments were performed in all cases. METHODS Two myopic astigmatism groups (CV centered using the offset between pupil center and normal corneal vertex and PC centered u...

Journal: :Arquivos brasileiros de oftalmologia 2012
Rong Fan Tao He Yan Qiu Yu-Lan Di Su-yun Xu Yao-yu Li

PURPOSE To evaluate the differences of wavefront aberrations under cycloplegic, scotopic and photopic conditions. METHODS A total of 174 eyes of 105 patients were measured using the wavefront sensor (WaveScan® 3.62) under different pupil conditions: cycloplegic 8.58 ± 0.54 mm (6.4 mm - 9.5 mm), scotopic 7.53 ± 0.69 mm (5.7 mm - 9.1 mm) and photopic 6.08 ± 1.14 mm (4.1 mm - 8.8 mm). The pupil ...

2017
Xiaoqin Chen Yan Wang Jiamei Zhang Shun-Nan Yang Xiaojing Li Lin Zhang

BACKGROUND To compare changes in higher-order aberrations (HOAs) following small incision lenticule extraction (SMILE) and wavefront-guided femtosecond laser-assisted in situ keratomileusis (WFG FS-LASIK), and to investigate correlations between preoperative spherical equivalence (SE) and components of HOAs affecting visual quality. METHODS Sixty-five myopic eyes from 38 patients were enrolle...

2001
Andrew Neureuther

Three radially symmetric and two first order rotational test targets were systematically tested for sensitivity and orthogonality by observing the change in the onaxis image intensity from the unaberrated cases in the presence of 0.05 waves peak of the corresponding 5 aberrations. The results are shown in Figure 4. Here each column corresponds to one of the test targets and each row corresponds...

Journal: :BMC Ophthalmology 2021

Abstract Background To evaluate early optical quality outcomes after small-incision lenticule extraction (SMILE) surgery for correcting high myopic astigmatism. Methods This retrospective study enrolled 55 eyes from 37 patients who had preoperative astigmatism of ≥2.00 diopters (D) been treated with SMILE surgery. Preoperatively, the mean cylinder was − 2.41 ± 0.54 D (range, 2.00 to 4.50 D). Th...

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