نتایج جستجو برای: refractive astigmatism
تعداد نتایج: 22191 فیلتر نتایج به سال:
Background and purpose: Astigmatism is a common optical dysfunction, effective on various visual outcomes and one of the important criteria of refractive surgery. The aim of present study was to evaluate the correlation between refractive, corneal and residual astigmatism in refractive surgery candidates. Materials and methods: In this cross-sectional descriptive, analytical study, 200 patient...
BACKGROUND To examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery. METHODS The study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-ker...
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 study the prevalence of and relation between refractive and corneal astigmatism in white school children in Northern Ireland and to describe the association between refractive astigmatism and refractive error. METHODS Stratified random clustering was used to recruit 1053 white children, 392 aged 6-7 years and 661 aged 12-13 years. Eye examinations included cycloplegic autorefractio...
Received: 10 March, 2009Accepted: 29 July, 2009 Abstract Background & Aims: Vision is an important indicator of health and life quality. The latest estimates of the World Health Organization indicate that there are 161 million visually impaired people worldwide. The most common reason for impaired vision may be refractive error. This research was performed to determine the frequency of re...
We investigated pseudophakic residual astigmatism in order to minimize postoperative refractive astigmatism. We examined 110 eyes of 87 patients who had undergone phacoemulsification with small incision and posterior chamber intraocular lens (IOL) implantation. Corneal astigmatism was measured using an autokeratometer (RK-5, canon), refractive astigmatism by manifest refraction, and residual as...
Background & Objectives: To determine the prevalence rates of refractive errors in Mashhad, Iran Methods: In this population-based study, random cluster sampling was performed on the urban population of Mashhad and of 4453 selected individuals, 70.4% participated in the study. Refractive errors were assessed using cycloplegic refraction in participants who were ≤ 15 years of age and non-cycl...
Introduction & Objective: This study was performed to compare the visual and refractive outcomes of photorefractive keratectomy (PRK) in eyes with medium-high astigmatism by WF-guided method using Visx system and cross-cylinder method using Nidek EC-5000 excimer laser system.?Although there are many studies about efficacy and safety of Wave front guided and Cross Cylinder Photorefractive Kera...
PURPOSE To evaluate the correlation between refractive, corneal, and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates. METHODS Three hundred and seventy-five eyes of 188 patients aged 28.2 ± 6.24 years with a predominance of females (62.7%) were enrolled in this study. Refraction, topography (Orbscan IIz, Bausch & Lomb, Rochester, NY, USA), and aberrome...
PURPOSE We estimated the contribution of the gradient refractive index (GRIN) and lens surfaces to lens astigmatism and lens astigmatic angle as a function of age in human donor lenses. METHODS Human lenses were imaged, ex vivo, with 3D-spectral optical coherence tomography (OCT) and their back focal length was measured using laser ray tracing. The contribution of lens surfaces and GRIN to le...
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