Search results for "ophthalmology"
showing 10 items of 1738 documents
Atrophic Forms (Dry AMD)
2009
Atrophic form of “Dry AMD” is defined by areas of RPE atrophy, often resulting from regression of confluent soft drusen.
Professor Dr Med Oskar Fehr: the fate of an outstanding German-Jewish ophthalmologist: an early contributor to cornea and external disease.
2014
PURPOSE The aim of this study was to recount the immense and abrupt change in the private and professional life of a prominent German-Jewish ophthalmologist in the transition from democracy to dictatorship in Germany during the first half of the 20th century. METHODS This involves a Retrospective analysis of Fehr's clinical and scientific work as the first assistant of Julius Hirschberg's world-famous eye clinic in Berlin; evaluation of Fehr's successful tenure as a chair of Virchow's Eye Hospital; the catastrophic influence of Hitler's seizure of power on the private and professional lives of German-Jewish physicians; and an analysis of Fehr's personal and professional will to continue the…
Lateral magnification matrix from the dioptric power matrix formalism in the paraxial case.
2012
Background Previous studies have highlighted that power matrices fully characterize the concept of dioptric power of any astigmatic surface. Thus, the basic equations in physiological optics can be generalized using the matrix formalism of the dioptric power. Among others, lateral magnification has also been interpreted as a matrix but mainly concerning magnification modification induced by spectacle correction of refractive error. Purpose To provide a fresh look into a novel paraxial formulation for the assessment of the lateral magnification using power matrices and in presence of astigmatism for thin and thick imaging systems in general. Methods Linear optics provides the frame to genera…
The effect of longitudinal chromatic aberration on the lag of accommodation and depth of field.
2016
Purpose Longitudinal chromatic aberration is present in all states of accommodation and may play a role in the accommodation response and the emmetropisation process. We study the change of the depth of field (DOFi) with the state of accommodation, taking into account the longitudinal chromatic aberration. Methods Subjective DOFi was defined as the range of defocus beyond which the blur of the target (one line of optotypes of 0.1 logMAR shown on a black-and-white microdisplay, seen through different colour filters) was perceived as objectionable. The subject's eye was paralysed and different, previously-measured accommodative states (corresponding to the accommodative demands of 0D, 2D and …
Power profiles in multifocal contact lenses with variable multifocal zone
2016
BACKGROUND The power profile of multifocal contact lenses has been demonstrated to report important information that could be used during the fitting process. The aim of this work is to describe the power profile of a recent set of gas permeable multifocal contact lenses as a function of the pupil radius. METHODS The measured multifocal contact lenses have a centre-distance design, and are available with five distance-vision diameters (XS, S, M, L and XL) and two different additions: Type A (up to +2.00 D) and Type B (up to +2.50 D). The optical device NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to obtain the power profile measurements. The optical lens power distribution as a functi…
Studying hypertension in ocular fundus images using Hausdorff dispersion ordering.
2010
Retinal arterial and vein diameters are altered in individuals at risk of cardiovascular events mainly due to high blood pressure. The measurement of retinal vessel diameters has been proved to reflect individuals' vascular health. Dispersion of such measures which are obtained by means of ocular fundus images is a major factor not usually considered in clinical research. In this paper, a method to evaluate if different levels of clinically relevant covariables induce greater dispersion in retinal arterial and vein diameters is proposed. A multivariate dispersion ordering, the Hausdorff dispersion order, is used to compare the level of dispersion in such diameters for different groups of pa…
Strain differences in the ratio of synaptic body types in photoreceptors of the rat retina.
1993
In the retinal outer plexiform layer of seven different rat strains, synaptic bodies (SB) were counted and, according to their morphology, characterized as synaptic ribbons (SR), synaptic spheres (SS) or intermediate structures. It was found that absolute SB numbers showed relatively small variations while SR/SS ratios differed considerably between the strains investigated. These results are discussed with respect to retinal pigmentation and to formation and degradation, respectively, of synaptic ribbons.
INTRAVITREAL BEVACIZUMAB FOR PROLIFERATIVE DIABETIC RETINOPATHY
2017
PURPOSE To evaluate the effects of intravitreal bevacizumab (IVB) on retinal neovascularization in patients with proliferative diabetic retinopathy (PDR). METHODS Retrospective multicenter interventional case series. A chart review was performed of 81 consecutive patients (97 eyes) with retinal neovascularization due to PDR, who received at least 1 IVB injection. RESULTS The mean age of the patients was 55.6 ± 11.6 years. The mean number of IVB injections was 4 ± 2.5 injections (range, 1-8 injections) per eye. The mean interval between IVB applications was 3 ± 7 months. The mean duration of follow-up was 29.6 ± 2 months (range, 24-30 months). Best-corrected visual acuity and optical coheren…
Ahmed valve, suture-less implantation: A new approach to an easier technique.
2013
Purpose Tissue adhesives have been used in ophthalmology instead of sutures to minimize the operating time. This case series investigated the effectiveness and safety of use of cyanoacrylate in Ahmed valve implantation through pars plana for refractory glaucoma. Patients and methods Seventeen eyes of 17 patients with refractory glaucoma underwent Ahmed valve scleral suture-less implantation through pars plana with a cyanoacrylate suture of the plate. Refractory glaucoma was defined as intraocular pressure (IOP) ≥ 21 mm Hg with antiglaucoma eye drops, good adherence to treatment, and no previous glaucoma surgery. IOP control and development of complications were evaluated during the follow-u…
Iris-fixated toric phakic intraocular lens: Three-year follow-up
2006
Purpose To evaluate the 3-year safety, efficacy, predictability, and stability of iris-fixated toric phakic intraocular lens (pIOL) implantation for the correction of myopia or hyperopia with astigmatism. Setting Department of Ophthalmology, Johannes Gutenberg University, Mainz, and Department of Ophthalmology, University Clinic, Bochum, Germany. Methods A prospective clinical trial of 40 eyes of 23 patients with high ametropia and astigmatism was conducted. Best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity, refraction, astigmatism, intraocular pressure, slitlamp biomicroscopy, and indirect ophthalmoscopy were measured preoperatively and postoperatively. Results Of t…