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showing 10 items of 710 documents
Corneal and Refractive Astigmatism in Adults: A Power Vectors Analysis
2009
Purpose. In this article, we examine the relationship between corneal and refractive astigmatism (including with the rule, against-the-rule, and oblique astigmatism) in an adult population using power vectors. Methods. Refractive and keratometric measures of astigmatism were conducted on right eyes of 105 white subjects aged 18 to 59 years. We performed a linear regression of refractive astigmatic error on corneal astigmatism, using the J0 and J45 components of the astigmatism. Results. We obtained a statistically significant regression relationship between the corneal (C) and refractive (R) astigmatism for both J0 and J45 components, namely, RJ0 = 1.07 × CJ0 − 0.28; and RJ45 = 1.46 × CJ45 …
Distribution of Anterior Chamber Angle Width and Correlation With Age, Refraction, and Anterior Chamber Depth—The Gutenberg Health Study
2016
PURPOSE Scheimpflug imaging allows quantitative analysis of the width of the anterior chamber angle. We report the population-based distribution of the anterior chamber angle width using this noncontact imaging technique and investigate associated factors. METHODS A population-based cross-sectional study was carried out in Germany. A comprehensive ophthalmologic examination including refraction, biometry, and Scheimpflug imaging was performed. Automated measurement of the anterior chamber angle was performed in each anterior chamber quadrant. Exclusion criteria were previous ocular surgery or inadequate image quality. Association analyses were carried out to determine independently associat…
Comparison of Dynamic Contour Tonometry and Goldmann Applanation Tonometry in Glaucoma Patients and Healthy Subjects
2006
To investigate the agreement in the measurement of intraocular pressure (IOP) obtained by dynamic contour tonometry PASCAL (DCT-PASCAL) and Goldmann applanation tonometry (GAT) in glaucoma eyes and healthy eyes with different central corneal thickness (CCT).Prospective cross-sectional study.In a randomized order, three consecutive IOP measurements were performed on 197 eyes of 107 subjects by one examiner using both DCT-PASCAL and GAT on all eyes. Furthermore, ultrasonic pachymetry was performed. The Spearman correlation coefficient (r) was determined to compare IOP readings between DCT-PASCAL and GAT. Regression-based Bland and Altman analysis was used to evaluate agreement between the ins…
The relationship between central corneal thickness and Goldmann applanation tonometry
2003
The aim of this study was to investigate the relationship between Goldmann applanation tonometry and central corneal thickness in a large sample of healthy eyes.Five hundred eyes of 500 subjects (253 women, 50.6 per cent and 247 men, 49.4 per cent) were analysed in a prospective healthy population study. Mean age of the sample was 31 +/- 8 years. Goldmann applanation tonometry was carried out by one physician. Tonometric values were the mean of three consecutive readings. Subsequently, another physician carried out ultrasonic pachymetry with the DGH 2000 AP ultrasonic pachymeter (DGH Technology Inc, San Diego, USA). Ten measurements were made at the centre of the cornea of each eye. The low…
Reproducibility of optical biometry using partial coherence interferometry: intraobserver and interobserver reliability
2001
Abstract Purpose: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). Setting: Johannes Gutenberg University, Mainz, Germany. Methods: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Me…
Interchangeability among five devices that measure anterior eye distances.
2014
The aim was to study the interchangeability of various devices that measure anterior chamber depth (ACD) and white-to-white (WTW) distance.Eighty right eyes of eighty patients aged 20 to 40 years were included. Their spherical equivalent ranged from -4.25 to +1.00 dioptres. Each eye's ACD and the WTW distance were measured using the following devices: a Castroviejo surgical calliper, CA-200F Corneal Analyser, Orbscan II, Pentacam HR and IOLMaster 500.The Pentacam HR measured significantly greater ACD (p0.01) than the other two devices, whereas IOLMaster 500 and Orbscan II yielded comparable (p0.01) distances. Nonetheless, in every device comparison, the mean difference was within clinically…
Association of Low Birth Weight With Altered Corneal Geometry and Axial Length in Adulthood in the German Gutenberg Health Study
2019
IMPORTANCE: Low birth weight is associated with altered ocular organ development in childhood, including the morphology of the eye. However, no population-based data exist about this association in adulthood. OBJECTIVE: To evaluate whether low birth weight has a long-term association with anterior segment anatomy and axial length in adulthood. DESIGN, SETTING, AND PARTICIPANTS: The Gutenberg Health Study is a population-based, observational cohort study in Germany. All participants underwent ocular biometry. Among the participants with follow-up and self-reported birth weight available, associations were assessed between low birth weight and anterior segment anatomy and axial length using m…
Topodiagnostic value of blink reflex R1 changes: a digital postprocessing MRI correlation study.
2001
The aim of the study was to investigate the relation of the blink reflex R1 arc to known anatomical brainstem structures. Acute vascular brainstem lesions as identified by magnetic resonance imaging (MRI) of patients with isolated R1 pathology were superimposed into a stereotactic anatomical atlas using a new method of digital postprocessing. Isolated acute brainstem lesions were documented by diffusion-weighted MRI in 12 of 24 patients with unilateral R1 pathology. The lesions were located in the ipsilateral mid- to lower pons. In three patients only, the lesion had partial contact with the principal sensory nucleus of the trigeminal nerve (PSN) on at least one level. In two patients, the …
Intrasubject repeatability of corneal power, thickness, and wavefront aberrations with a new version of a dual rotating Scheimpflug–Placido system
2014
Purpose To determine the intrasubject repeatability of a recently introduced dual-camera rotating Scheimpflug–Placido imaging system (Galilei G4) in determining corneal thickness, power, and wavefront aberrations in young healthy subjects. Setting University of Valencia, Valencia, Spain. Design Prospective evaluation of diagnostic technology. Methods The study comprised right eyes of 25 subjects aged 20 to 40 years with a spherical equivalent ranging from −4.25 to +1.00 diopters. The central corneal thickness, thinnest point value and location, anterior and posterior surface curvatures, total corneal power, and corneal wavefront aberrations were measured for distance vision using the dual S…
Repeatability of whole-cornea measurements using an anterior segment imaging device based on OCT and Placido-disk
2017
Current advances in refractive surgery require high accuracy of corneal measurements. We aim to evaluate the repeatability of topographic measurements using an integrated Placido disk - OCT device.Thirty right eyes of thirty healthy and young subjects were included. The topographic parameters of simulated keratometry, asphericity, minimum pachymetry, white-to-white distance, spherical aberration and corneal elevation were studied. Three measurements were taken by the same observer using the Visante omni device. The coefficient of repeatability (CoR), coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the repeatability. The Bland-Altman grap…