Search results for "corneal hysteresis"
showing 9 items of 9 documents
Modificación de la histéresis corneal y su influencia en la cirugía de glaucoma y en la biomecánica del nervio óptico
2013
El principal factor de riesgo para el desarrollo de la neuropatía óptica glaucomatosa y el único en el que podemos actuar hoy en día es la elevación de la presión intraocular, por lo que cobra extrema importancia la exquisitez en la determinación del parámetro en el que va a girar nuestra actitud. Sin embargo, existen múltiples situaciones donde los pacientes, a pesar de tener la PIO en límites normales, continúan progresando. Se han apuntado múltiples causas para este fenómeno como la fluctuación de la PIO o el aumento nocturno de la PIO por el decúbito supino; pero la aparición del concepto de histéresis ocular planteó nuevos interrogantes desde 2 puntos de vista principalmente. El primer…
Impact of Corneoscleral Contact Lens Usage on Corneal Biomechanical Parameters in Keratoconic Eyes
2019
Objective To analyze the changes in corneal biomechanical parameters of keratoconic eyes with and without intracorneal ring segment (ICRS) implants after 1 year of corneoscleral contact lens (CScL) wear. Methods Seventy-four eyes of 74 patients were divided into three groups: healthy subjects (29 eyes, control group), and 2 groups of subjects with keratoconic eyes (one group of 20 eyes with ICRS implants and one of 25 eyes without them), which were fitted with CScL. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated before fitting CScL and after 1 year of CScL wear. In addition, endothelial cell count (ECC) and centr…
Anterior Segment Biometry and Their Correlation with Corneal Biomechanics in Caucasian Children.
2018
Purpose: To assess the relationship between the corneal biomechanical parameters and the anterior segment parameters in Caucasian children. Methods: This study included 293 eyes from 293 healthy children aged between 6 and 17 years. Corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer, axial length (AL) with IOLMaster and the anterior segment with Pentacam. Anterior segment parameters obtained were the following: central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and mean anterior and posterior keratometry. Two multiple linear regression models were constructed to assess th…
Corneoscleral contact lenses for visual rehabilitation after keratoplasty surgery.
2019
Abstract Purpose To report the use of corneoscleral lenses (CSL) in keratoconus patients who were unsatisfied with their visual outcomes after keratoplasty surgery. Methods Eleven consecutive cases with unsatisfactory vision with spectacles, due to irregular astigmatism, preferred to try CSL before SL due to handling or economic issues. An eye examination included refraction and visual acuity assessment, anterior eye biomicroscopy, ocular fundus examination, corneal topographic analysis, endothelial-cell count (ECC) and evaluation of corneal biomechanical parameters (corneal resistance factor, CRF; corneal hysteresis, CH; corneal-compensated intraocular pressure, IOPcc). The fitting process…
Corneal Biomechanical Parameters With Corneoscleral Contact Lenses in Post-Laser In Situ Keratomileusis Eyes
2018
Objective: To evaluate corneal biomechanical parameters wearing corneoscleral contact lenses (CScL) in patients with irregular corneas after laser in situ keratomileusis (LASIK). Methods: Data from patients fitted with CScL because of corneal surface irregularities after complicated LASIK surgery were selected by two eye clinics. Previously and after 1 year of CScL fitting, corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and central corneal thickness were evaluated. In addition, visual acuity, subjective comfort, and wearing time CScL were reported. Results: The study comprised 27 eyes. Statistically significant differences were fo…
Corneal Biomechanical Parameters and Central Corneal Thickness in Glaucoma Patients, Glaucoma Suspects, and a Healthy Population
2021
Purpose: To evaluate and compare corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), measurements were taken between a healthy population (controls), patients diagnosed with glaucoma (DG), and glaucoma suspect patients due to ocular hypertension (OHT), family history of glaucoma (FHG), or glaucoma-like optic discs (GLD). Additionally, Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated IOP (IOPcc) were compared between the different groups of patients. Methods: In this prospective analytical-observational study, a total of 1065 patients (one eye of each) were recruited to undergo Ocular Response Analyzer (ORA) testing, ultrasoun…
Influence of Corneal Opacity on Intraocular Pressure Assessment in Patients with Lysosomal Storage Diseases
2017
Aims To investigate an influence of mucopolysaccharidosis (MPS)- and Morbus Fabry-associated corneal opacities on intraocular pressure (IOP) measurements and to evaluate the concordance of the different tonometry methods. Methods 25 MPS patients with or without corneal clouding, 25 Fabry patients with cornea verticillata ≥ grade 2 and 25 healthy age matched controls were prospectively included into this study. Outcome measures: Goldmann applanation tonometry (GAT); palpatory assessment of IOP; Goldmann-correlated intraocular pressure (IOPg), corneal-compensated intraocular pressure (IOPcc), corneal resistance factor (CRF) and corneal hysteresis (CH) assessed by Ocular Response Analyzer (ORA…
Are Ocular Response Analyzer useful to measure corneal hysteresis in patients with intracorneal rings?
2008
Purpose Corneal hysteresis is a viscoelastic property characterized by the difference in behavior under loading and unloading. The aim of the study was to determine corneal hysteresis in different eyes: healthy eyes, keratoconic eyes and keratoconic eyes after intracorneal ring implants. Methods This study comprised 95 eyes of 59 patients. The study population was divided into 3 groups. We analyze 30 healthy human eyes, 35 keratoconic eyes (Amsler grade II-III) and 30 keratoconic eyes after intracorneal rings implantation. Corneal biomechanical properties of these eyes were measured with the Ocular Response Analyser (ORA-Reichert) according to two parameters: corneal hysteresis (CH) and cor…
Tonographic Effect of Ocular Response Analyzer in Comparison to Goldmann Applanation Tonometry.
2016
AIMS The tonographic effect is a phenomenon of intraocular pressure (IOP) reduction following repeated tonometry. This study examines whether the tonographic effect occurs following IOP measurement performed with Ocular Response Analyzer (ORA). METHODS Both eyes of 31 glaucoma patients and 35 healthy controls underwent nine IOP-measurements performed with GAT and ORA. The number of GAT and ORA measurements performed on each eye differed depending on the randomly allocated investigation scheme. Central corneal thickness (CCT), anterior chamber volume (ACV) and anterior chamber depth (ACD) were assessed with Pentacam before and after the repeated GAT/ORA measurements. RESULTS There was no sta…