Search results for "ASTIGMATISM"

Visual Acuity in Simple Myopic Astigmatism: Influence of Cylinder Axis

2006

Purpose. The relationship between astigmatic refractive errors and their associated visual acuity has been studied in recent years in the context of refractive power space. The influence of the axis of astigmatism remains a matter of controversy. Our goal in this study is to provide additional experimental evidence to clarify this subject. The influence of the simulated axis orientation was compared with other factors that affect visual acuity such as the particular design of the test and the differences between eyes. Methods. Simple myopic astigmatism from 0 to 3.00 D, in steps of 0.25 D, and with five different axes between 0° and 90°, were simulated on four healthy eyes of young observer…

Impact of the line of sight on toric phakic intraocular lenses for hyperopia

2003

We present a hyperopic patient with a decentered line of sight in whom the residual refractive error after toric phakic intraocular lens (TP IOL) implantation was improved by displacement and individualized treatment. A 35-year-old woman presented with asthenopic complaints 2 months after bilateral TP IOL implantation and IOL rotation 4 weeks later. Examination revealed the line of sight to be nasally and inferiorly decentered in relation to the center of the pupil. A more nasal reenclavation of the TP IOL decreased the coma, and the uncorrected visual acuity was 20/20. We conclude that line of sight should be measured before TP IOL implantation, especially in hyperopic eyes.

Behaviour of the phakic iris-claw intraocular lens (Artisan /Verisyse) during accommodation: an optical coherence biometry study.

2007

Purpose To evaluate variations in the position of the phakic iris claw lens (Artisan®, Verisyse®) and the natural crystalline lens during the accommodation process. Methods We measured changes in position of the iris claw lens and the crystalline lens during the accommodation using optical coherence biometry (AC Master®/Carl Zeiss Meditec, Germany) in 17 patients (28 eyes) with a phakic iris claw lens implanted for high myopia and/or myopic astigmatism. Accommodative effort was obtained using an internal optical target within the measuring device. Results There was a forward shift of the phakic iris claw lens with a mean of 70 μm (8–178 μm) of the optical path length (OPL). At the same time…

The effect of simulated normal and amblyopic higher-order aberrations on visual performance.

2012

Purpose To study the effect of simulated amblyopic and normal higher-order aberrations on visual performance of normal eyes. Methods To assess visual function, an adaptive optics visual simulator was used to compensate volunteers' ocular aberrations and simulate the wavefront aberration patterns found in healthy and amblyopic eyes in 7 healthy individuals. Visual acuity for high (100%), medium (50%), and low (10%) contrast and contrast sensitivity at 10, 20, and 25 cycles per degree (cpd) were measured after simulation of both pattern aberrations. The modulation transfer function and the point spread function were computed based on the aberration data. All measures were taken for 3 and 5.5 …

Contrast sensitivity after implantation of toric iris-claw lenses in phakic eyes.

2004

Abstract Purpose: To evaluate the change in contrast sensitivity after implantation of the Verisyse toric phakic intraocular lens (IOL) (AMO) for the correction of myopia with astigmatism. Setting: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods: Eighteen eyes had implantation of an iris-supported toric phakic IOL to correct myopia with astigmatism. The mean preoperative spherical equivalent was −12.65 diopters ± 3.6 (SD). The contrast sensitivity with best spectacle correction was determined before surgery and 3 months after surgery using the CSV-1000 HGT instrument (Vector Vision Inc.). Results: Three months after IOL implantation, the mean contrast sen…

Heritability of refractive astigmatism: a population-based twin study among 63- to 75-year-old female twins.

2013

PURPOSE: To examine the heritability of refractive astigmatism in older women. METHODS: Astigmatism was measured with an autorefractor in 88 monozygotic and 82 dizygotic female twin pairs aged 63 to 75 years. The prevalence and distribution of astigmatism and polar values J0 and J45 were estimated by standard statistical methods. Bivariate maximum likelihood model fitting was used to estimate genetic and environmental variance components using information from both eyes. RESULTS: Mean astigmatism of the more astigmatic eye was 0.93 diopters (D; SD ±0.58). Astigmatism of at least 0.25 D, 0.5 D, 0.75 D, or 1.0 D in either eye was present in 99.7%, 88.5%, 66.5%, and 46.2% of cases, respectivel…

Axial Length and Anterior Segment Alterations in Former Preterm Infants and Full-Term Neonates Analyzed With Scheimpflug Imaging.

2017

Purpose To compare the axial length and anterior segment alterations in preterm infants with and without retinopathy of prematurity with those of full-term infants. Methods The Wiesbaden Prematurity Study investigated 503 participants of former gestational age ≤32 weeks and gestational age ≥37 weeks now being aged 4 to 10 years. This study included 485 participants in the prospective controlled cross-sectional, hospital-based study with successful Pentacam Scheimpflug imaging. Anterior segment parameters, axial length measurements, and associated factors were analyzed. Results Corneal thickness did not differ between former preterm and full-term infants. Significant differences were found b…

2017

Purpose To analyze the effect of birth weight on ocular morphology, refraction and visual function in early adolescents aged 12–15 years. Material and methods We conducted a secondary data analysis using the public use files from the National Health and Nutrition Examination Survey of the period from 1999 to 2008. Study participants aged 12 to 15 years were included with data on birth weight and ophthalmic parameters including presenting distance visual acuity, objective refraction and keratometry. Visual acuity, sphere, astigmatism in power vectors J0 and J45, corneal power and corneal astigmatism were evaluated for an association with birth weight. Linear and logistic regression with adju…

Le incisioni rilassanti limbari per la correzione dell'astigmatismo nei soggetti con impianto di IOL multifocali

2004

Comparison of subconjunctival microinvasive glaucoma surgery and trabeculectomy

2021

Purpose To assess surgical success and the post-operative development of intraocular pressure between XEN45® gelstent, Preserflo® MicroShunt and trabeculectomy with mitomycin C. Methods Data from 105 eyes from 105 patients of matched cases with refractory open-angle glaucoma, who underwent surgery between January 2019, and August 2020, were evaluated. Patients underwent either stand-alone XEN gelstent insertion with Mitomycin C, stand-alone Preserflo with Mitomycin C or trabeculectomy with Mitomycin C. The primary outcome was the proportion of complete surgical success at 6 months post-operatively (i.e. intraocular pressure between 5mmHg and 18mmHg, no revision surgery, no loss of light per…