نتایج جستجو برای: postkeratoplasty astigmatism

تعداد نتایج: 3072  

Journal: :European journal of ophthalmology 2009
Shai Bar-Sela Yoseph Glovinsky Tamara Wygnanski-Jaffe Abraham Spierer

PURPOSE To evaluate the magnitude of refractive astigmatism after congenital cataract surgery and to define its correlation with patient age. METHODS The authors retrospectively reviewed the charts of all pediatric patients who underwent congenital cataract extraction with intraocular lens (IOL) implantation through a 3.0-mm clear corneal incision from 1998 to 2003, and had no suture removal ...

2018
David F Anderson Mukesh Dhariwal Christine Bouchet Michael S Keith

Purpose To systematically review the published evidence on the prevalence and economic and humanistic burden of astigmatism in cataract patients. Materials and methods For this systematic literature review, the Medline, PubMed, Embase, and Cochrane databases were searched from 1996 to September 2015 for available scientific literature that met the inclusion criteria. Studies published in the ...

2012
Steven M Christiansen Mark D Mifflin Jason N Edmonds Rachel G Simpson Majid Moshirfar

BACKGROUND The purpose of this study was to evaluate surgically-induced astigmatism after spherical ablation in photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK) for myopia with astigmatism < 1.00 D. METHODS The charts of patients undergoing spherical PRK or LASIK for the correction of myopia with minimal astigmatism of <1.00 D from 2002 to 2012 at the John A...

Journal: :Vision Research 2010
Pablo de Gracia Carlos Dorronsoro Enrique Gambra Gildas Marin Martha Hernández Susana Marcos

We demonstrate that certain combinations of non-rotationally symmetric aberrations (coma and astigmatism) can improve retinal image quality over the condition with the same amount of astigmatism alone. Simulations of the retinal image quality in terms of Strehl Ratio, and measurements of Visual Acuity under controlled aberrations with adaptive optics were performed, varying defocus, astigmatism...

Journal: :Vision Research 2000
Jane Gwiazda Kenneth Grice Richard Held James McLellan Frank Thorn

While it is now established that astigmatism is more prevalent in infants and young children than in the adult population, little is known about the functional significance of this astigmatism, especially its role, if any, in emmetropization and the development of myopia. Manifest refractions (mean of 16 per subject) were obtained from 245 subjects starting in the first year, with 6-23 years of...

2012
Dieudonne Kaimbo Wa Kaimbo

1.1 Definition Astigmatism (from the Greek “a” meaning absence and “stigma” meaning point) is a refractive error (ametropia) that occurs when parallel rays of light entering the nonaccommoding eye are not focused on the retina [American Academy of Ophthalmology (AAO), 2007]. Astigmatism occurs when incident light rays do not converge at a single focal point. The cornea of the normal eye has a u...

Journal: :Journal of cataract and refractive surgery 2012
Hidenaga Kobashi Kazutaka Kamiya Kimiya Shimizu Takushi Kawamorita Hiroshi Uozato

PURPOSE To determine the effect of axis orientation on visual performance in astigmatic eyes. SETTING Department of Ophthalmology, Kitasato University, Kanagawa, Japan. DESIGN Investigational simulation. METHODS Healthy volunteers with no ophthalmic disease other than refractive errors were enrolled. After cycloplegic refraction was fully corrected with a 3.0 mm artificial pupil, with-the...

2017
Pisong Yan Zhiyu Du Yu Zhang

PURPOSE To evaluate the astigmatic outcomes of wavefront-guided sub-Bowman keratomileusis (WFG-SBK) for low to moderate myopic astigmatism. METHODS This study enrolled 100 right eyes from 100 patients who underwent WFG-SBK for the correction of myopia and astigmatism. The polar value method was performed with anterior and posterior corneal astigmatism measured with Scheimpflug camera combined...

Journal: :Investigative ophthalmology & visual science 1984
V Dobson A B Fulton S L Sebris

Review of the cycloplegic refractions of all children who were first examined at Children's Hospital Medical Center in Boston between 1968 and 1978 revealed that 281 children between the ages of 0 and 9.5 years had astigmatism of 1 diopter (D) or greater but no other ophthalmological or neurological problems. In the 85 children under 3.5 years of age, against-the-rule astigmatism was 2.5 times ...

2017
Manoj Motwani

PURPOSE To demonstrate how higher-order corneal aberrations can cancel out, modify, or induce lower-order corneal astigmatism. PATIENTS AND METHODS Six representative eyes are presented that show different scenarios in which higher-order aberrations interacting with corneal astigmatism can affect the manifest refraction. WaveLight® Contoura ablation maps showing the higher-order aberrations a...

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