Search results for " Intraocular"
showing 10 items of 215 documents
Modulation transfer function in refractive-diffractive multifocal intraocular lenses in vitro
2007
Purpose: The optical quality of two types of multifocal, hybrid refractive-diffractive, intraocular lenses (IOL) is analyzed in vitro. Following the EN-ISO international standard, the IOLs’ modulation transfer functions (MTF) are determined for both distance and near vision. The behaviour of these curves when the pupil size varies is studied. Methods: The IOLs analyzed were: AcrySoft ResTor SN60D3 (Alcon) and Tecnis ZM900 (AMO). The MTF was calculated from the cross line-spread function recorded with the OPAL Vector System (Image Science Ltd. Oxford) by using fast Fourier transform techniques. The artificial eye model used simulates in vivo conditions of the anterior chamber including an ar…
Visual and refractive outcomes in hyperopic pseudophakic patients implanted with a trifocal intraocular lens
2019
José F Alfonso,1,2 Andrés Fernández-Vega-Cueto,1 Belén Alfonso-Bartolozzi,1 Ignacio Rodríguez-Uña,1 Robert Montés-Micó3 1Corneal and Lens Surgery Department, Fernández-Vega Ophthalmological Institute, Oviedo, Spain; 2Surgery Department, School of Medicine, University of Oviedo, Oviedo, Spain; 3Optics and Optometry and Vision Sciences Department, Faculty of Physics, University of Valencia, Valencia, SpainCorrespondence: José F AlfonsoInstituto Oftalmológico Fernández-Vega, Avda. Dres. Fernández-Vega 114, Oviedo 33012, SpainTel +34 985 245533Fax +34 98…
Endothelial cells loss to the hyperopic pacients during phacoemulsification
2018
Introduction The phacoemulsification cataract surgery is the most frequently performed surgery and it generally improves vision in over 90% of the patients. Hyperopic patients are a challenge during phacoemulsification especially because of their short eyeball and shallow anterior chamber. A shallow anterior chamber is associated with overall reduction of the safe zone, which may lead to difficulty in creating the corneal incisions, harder capsulorhexis performing, or endothelial complications. Purpose The aim of the study was to present the endothelial cells loss after the phacoemulsification procedure in the hyperopic patients. Material and methods A number of 1775 patients operated in th…
Optical solutions for the human eye with progressive loss of accommodation. Effect of the pupil.
2016
La presbicia se define como una reducción lenta, natural, irreversible, y relacionada con la edad de la máxima amplitud de acomodación, suficiente como para causar síntomas de borrosidad y astenopia en visión próxima. Afortunadamente, se han desarrollado varios sistemas ópticos que mejoran esta sintomatología y ayudan a recuperar las capacidades visuales para trabajar en visión próxima. Por otro lado, el análisis in-vitro permite obtener resultados objetivos de los sistemas ópticos y así ampliar el conocimiento del rendimiento óptico de estos sistemas. La presente tesis doctoral estudia la calidad óptica in-vitro de lentes de contacto e intraoculares. Se utilizaron dos sistemas in-vitro par…
Determining postoperative anterior chamber depth
2003
Abstract Purpose: To compare measured and calculated postoperative anterior chamber depths (ACDs). Setting: Department of Ophthalmology and Institute of Medical Physics, University of Vienna, Vienna, Austria, and Department of Ophthalmology, University of Mainz, Mainz, Germany. Methods: The postoperative ACD was measured in 189 pseudophakic eyes using a laboratory prototype of partial coherence interferometry (PCI). In 6 intraocular lens (IOL) groups, the mean ACD was calculated by ray tracing based on the best-known A-constants of the SRK formulas. In addition, for each IOL type, each measured ACD was compared with a value calculated using the individual spherical equivalent of the postope…
Implantable collamer lens with central hole: 3-year follow-up.
2018
Luis Fernández-Vega-Cueto,1 Carlos Lisa,1 José J Esteve-Taboada,2 Robert Montés-Micó,2 José F Alfonso1,3 1Department of Surgery, Fernández-Vega Ophthalmological Institute, Oviedo, Spain; 2Department of Optics and Optometry and Visual Sciences, University of Valencia, Valencia, Spain; 3School of Medicine, University of Oviedo, Oviedo, Spain Purpose: To evaluate the long-term predictability, stability, safety, and efficacy of the V4c Visian implantable collamer lens (ICL) with central hole to correct myopia.Patients and methods: One hundred and eighty-four eyes of 92 patients were evaluated during 3 years after implantation of …
Autoimmunity and Glaucoma
2008
Elevated intraocular pressure does not explain glaucoma in all patients, but there is information that autoimmune mechanisms may be involved in this disorder. This review attempts to reveal the findings about specific changes in autoantibody profiles in glaucoma patients and their possible role in glaucoma. Considering that these changes in natural autoimmunity can be found consistently among different study populations, it might be a promising new tool for glaucoma detection.
Implantation of a custom intraocular lens with a 30-diopter torus for the correction of high astigmatism after penetrating keratoplasty.
2003
Abstract We present a 62-year-old woman who had implantation of an intraocular lens (IOL) with a torus of 30.0 diopters (D) in an eye after penetrating keratoplasty. The patient presented with cataract and a best corrected visual acuity of 20/400. Penetrating keratoplasty was performed in 1975 because of decompensated keratoconus. With a clear but inferiorly decentered corneal graft, visual acuity was limited because of keratoplasty-related high corneal astigmatism of 22.5@156 that could not be successfully treated with spectacles or contact lenses. A custom toric IOL with –30.0 D of cylindrical power was implanted in the capsular bag via a sclerocorneal tunnel incision. Additionally, a sph…
Optical analysis to predict outcomes after implantation of a double intraocular lens magnification device.
2007
Purpose To analyze the effect of different optical parameters of the eye on the outcomes of implantation of a double intraocular lens (IOL) magnification device in patients with low vision. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods The eye's refraction and magnification before and after surgery were evaluated using a theoretical eye model based on paraxial optics approximation. Four parameters on which refraction and magnification are dependent were evaluated: anterior chamber depth (ACD), axial length (AL), mean keratometry (Km), and the distance between the 2 implanted IOLs. The 4 variables were analyzed separately in the first stage. Next, different combi…
Toric phakic intraocular lens
2003
Abstract Objective To evaluate safety, efficacy, predictability, stability, complications, and patient satisfaction after implantation of Artisan toric phakic intraocular lenses (TPIOLs) for the correction of myopia or hyperopia with astigmatism. Design Prospective, nonrandomized, comparative (self-controlled) multicenter trial. Participants Seventy eyes of 53 patients (mean, 35 years; range, 22–59 years) with preoperative spherical equivalent between +6.50 and −21.25 diopters (D) and cylinder between 1.50 and 7.25 D. Methods Seventy eyes underwent implantation of a TPIOL with an optical zone of 5.0 mm (Artisan, Ophtec, Groningen, The Netherlands). The dioptric power of the intraocular lens…