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ocular response analyzer cornea

Ying Hon, Guo-Zhen Chen, Shu-Hao Lu, David C C Lam, Andrew K C Lam
PURPOSE: To compare corneal tangent moduli between low and high myopes. METHODS: Corneal hysteresis (CH) and corneal resistance factor (CRF) of 32 low and 32 high myopes were obtained using an Ocular Response Analyzer, followed by a corneal indentation device that measured corneal stiffness. Corneal topography, pachymetry, Goldmann applanation tonometry intraocular pressure (GAT-IOP), and corneal compensated intraocular pressure (IOPcc) were also obtained. Corneal tangent modulus was calculated on the basis of corneal stiffness, central corneal thickness and corneal radius...
November 21, 2016: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
Qian Sun, Zheng-Zheng Deng, Yue-Hua Zhou, Jing Zhang, Xiao-Yan Peng
AIM: To compare the corneal biomechanical outcomes at one year after laser in situ keratomileusis (LASIK) with the flaps created by Ziemer and Moria M2 microkeratome with 110 head and -20 blade. METHODS: Totally 100 eyes of 50 consecutive patients were enrolled in this prospective study and divided into two groups for corneal flaps created by ZiemerFemto LDV and Moria M2 microkeratome with 110 head and -20 blade. Corneal biomechanical properties including cornea resistance factor (CRF) and cornea hysteresis (CH) were measured before and 1, 3, 6, 12mo after surgery by ocular response analyzer...
2016: International Journal of Ophthalmology
Yusuf Yıldırım, Onur Ölçücü, Abdurrahman Başcı, Alper Ağca, Engin Bilge Özgürhan, Cengiz Alagöz, Ali Demircan, Ahmet Demirok
OBJECTIVES: To compare the postoperative biomechanical properties of the cornea after photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) in eyes with low and moderate myopia. MATERIALS AND METHODS: We retrospectively examined 42 eyes of 23 patients undergoing PRK and 42 eyes of 22 patients undergoing SMILE for the correction of low and moderate myopia. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with an Ocular Response Analyzer before and 6 months after surgery...
April 2016: Turkish Journal of Ophthalmology
Michael A Bergen, Han Na Park, Ranjay Chakraborty, Erica G Landis, Curran Sidhu, Li He, P Michael Iuvone, Machelle T Pardue
Purpose: The neuromodulator dopamine (DA) has been implicated in the prevention of excessive ocular elongation and myopia in various animal models. This study used retina-specific DA knockout mice to investigate the role of retinal DA in refractive development and susceptibility to experimental myopia. Methods: Measurements of refractive error, corneal curvature, and ocular biometrics were obtained as a function of age for both untreated and form-deprived (FD) groups of retina-specific tyrosine hydroxylase knockout (rTHKO) and control (Ctrl) mice...
August 1, 2016: Investigative Ophthalmology & Visual Science
Mehtap Caglayan, Ozge Sarac, Pinar Kosekahya, Sukran Erten, Berna Ayan, Nurullah Cagil
PURPOSE: The aim of this study was to evaluate the corneal biomechanical parameters in patients with ankylosing spondylitis (AS) and to compare them with the healthy subjects. METHODS: Sixty patients with AS (study group) and 60 healthy subjects (control group) were enrolled in this prospective study. The study group was further classified as active (n:30) and inactive (n:30). After detailed ophthalmological examination including intraocular pressure (IOP) measurement with Goldmann applanation tonometer (IOPGAT), corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated IOP (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with the Reichert Ocular Response Analyzer (ORA)...
October 5, 2016: International Ophthalmology
S E Avetisov, V R Mamikonyan, O A Shmeleva-Demir, A A Karamyan, I A Bubnova, E E Kazaryan, N S Galoyan, A T Karapetyan
AIM: to study changes in intraocular pressure (IOP), volumetric ocular blood flow (OBF) rate, and biomechanical properties of the cornea after excimer laser ablation in patients with myopia of different degrees. MATERIAL AND METHODS: A total of 16 patients (32 eyes) with myopia ranging from 2.75 to 9.0 D were examined before and after LASIK. Ocular Blood Flow Analyzer (OBFA) was used to measure IOP and OBF as well as pulse amplitude and volume. Ocular Response Analyzer (ORA) was also employed to provide the following data: Goldmann-equivalent IOP, corneal compensated IOP, corneal hysteresis, and corneal resistance factor...
July 2016: Vestnik Oftalmologii
Kunliang Qiu, Xuehui Lu, Riping Zhang, Geng Wang, Mingzhi Zhang
Purpose. To determine the corneal biomechanical properties by using the Ocular Response Analyzer™ and to investigate potential factors associated with the corneal biomechanics in healthy myopic subjects. Methods. 135 eyes from 135 healthy myopic subjects were included in this cross-sectional observational study. Cornea hysteresis (CH), corneal resistance factor (CRF), cornea-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure (IOPg) were determined with the Reichert Ocular Response Analyzer (ORA)...
2016: Journal of Ophthalmology
Ali Bülent Çankaya, Seyfullah Kan, Muhammed Kizilgul, Aslı Tokmak, Merve Inanc, Mustafa Caliskan, Emrullah Beyazyildiz, Ugur Açar, Tuncay Delibaşı
The purpose of this study is to compare the corneal biomechanical properties in primary hyperparathyroid patients and healthy control subjects. The study consisted of 31 patients with primary hyperparathyroidism (study group) and 31 healthy subjects (control group). Corneal biomechanical properties, including corneal hysteresis (CH), corneal resistance factor (CRF), and intraocular pressure (IOP) were measured with an ocular response analyzer (ORA). IOP was also measured using Goldmann applanation tonometry (GAT), and central corneal thickness (CCT) was measured with an ultrasonic pachymeter...
July 16, 2016: International Ophthalmology
Allan Luz, Bernardo Lopes, Katie M Hallahan, Bruno Valbon, Isaac Ramos, Fernando Faria-Correia, Paulo Schor, William J Dupps, Renato Ambrósio
PURPOSE: To evaluate the performance of the Ocular Response Analyzer (ORA) (Reichert Ophthalmic Instruments, Depew, NY) variables and Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) tomographic parameters in differentiating forme fruste keratoconus (FFKC) from normal corneas, and to assess a combined biomechanical and tomographic parameter to improve outcomes. METHODS: Seventy-six eyes of 76 normal patients and 21 eyes of 21 patients with FFKC were included in the study...
July 1, 2016: Journal of Refractive Surgery
Xue-Fei Song, Achim Langenbucher, Zisis Gatzioufas, Berthold Seitz, Moatasem El-Husseiny
AIM: To determine the impact of biometric characteristics on the biomechanical properties of the human cornea using the ocular response analyzer (ORA) and standard comprehensive ophthalmic examinations before and after standard phacoemulsification. METHODS: This study comprised 54 eyes with cataract with significant lens opacification in stages I or II that underwent phacoemulsification (2.8 mm incision). Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) were measured by ORA preoperatively and at 1mo postoperatively...
2016: International Journal of Ophthalmology
Ayse Ebru Kilavuzoglu, Ali Riza Cenk Celebi, Ugur Emrah Altiparmak, Cemile Banu Cosar
PURPOSE: To determine the effect of smoking on corneal biomechanical behavior. MATERIALS AND METHODS: The medical records of consecutive patients that presented to the ophthalmology department were reviewed. History of smoking and ophthalmological examination findings were recorded. The smoking group met the following criteria: a clear history of and present smoking habit, negative history of corneal disease and surgery, ocular response analyzer measurement at the time of examination, and a waveform score ≥3...
June 3, 2016: Current Eye Research
Almamoun Abdelkader
BACKGROUND: To evaluate, using a rabbit model, the influence of the wound healing process at the flap edge on corneal biomechanics after sutured, glued, and non-augmented microkeratome flaps. METHODS: Unilateral 160 μm thick laser in situ keratomileusis (LASIK) flaps using a mechanical microkeratome were performed on the corneas of the left eyes of 36 rabbits. Animals were then divided into 3 groups of 12 rabbits each: A: the flaps were glued with human fibrin tissue adhesive (Tisseel); B: the flaps were sutured; and C: the flaps were allowed to heal without the use of sutures or glue (non-augmented)...
2016: Eye and Vision (London, England)
Zofia Pniakowska, Anna Klysik, Roman Gos, Piotr Jurowski
AIM: To determine the relevance of the objective parameters addressing the altered biomechanical properties of cornea for glaucoma monitoring in patients with mild or moderate thyroid associated orbitopathy (TAO), and in healthy individuals. METHODS: Twenty-five patients with TAO (group 1) and 25 healthy adults (group 2) were included to the study. Both groups were of a similar age and the ratio women:man. For each patient, the following parameters of both eyes were measured with ocular response analyzer (ORA): corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg) and corneal compensated intraocular pressure (IOPcc)...
2016: International Journal of Ophthalmology
Ken T Simmons, Yangyan Xiao, Stephen C Pflugfelder, Cintia S de Paiva
PURPOSE: Toll-like receptor 4 (TLR4) alerts cells to the presence of bacteria by initiating an inflammatory response. We hypothesize that disruption of the ocular surface barrier in dry eye enhances TLR4 signaling. This study determined whether dry eye enhances expression of inflammatory mediators in response to topically applied TLR4 ligand. METHODS: A single dose of lipopolysaccharide (LPS) or vehicle (endotoxin-free water) was applied to the cornea of nonstressed (NS) mice or mice subjected to 5 days of desiccating stress (DS)...
May 1, 2016: Investigative Ophthalmology & Visual Science
Karin R Pillunat, Cosima Hermann, Eberhard Spoerl, Lutz E Pillunat
PURPOSE: The purpose was to investigate a possible association of corneal hysteresis (CH) and corneal resistance factor (CRF) with open-angle glaucoma and the severity of disease. METHODS: In this prospective cross-sectional study we recruited 86 open-angle glaucoma patients, 16 patients with ocular hypertension (OHT,) and 44 age-matched controls. Each participant had a complete glaucoma workup including measurements with the Ocular Response Analyzer and computerized perimetry with the Humphrey 30-2 SITA Standard program...
July 2016: Graefe's Archive for Clinical and Experimental Ophthalmology
Cedric Schweitzer, Jean-Francois Korobelnik, Mathieu Boniol, Audrey Cougnard-Gregoire, Melanie Le Goff, Florence Malet, Marie-Benedicte Rougier, Marie-Noelle Delyfer, Jean-Francois Dartigues, Cecile Delcourt
PURPOSE: The purpose of this study was to assess the associations of biomechanical properties of the cornea with metabolic and environmental factors in an elderly population. METHODS: The ALIENOR (Antioxydants, Lipides Essentiels, Nutrition, and Maladies OculaiRes) study is a population-based study. In 2009-2010, 624 subjects, aged 74 years or more, underwent an eye examination, including intraocular pressure (IOP), central corneal thickness (CCT), and biomechanical properties of the cornea measurements using the Ocular Response Analyzer...
April 1, 2016: Investigative Ophthalmology & Visual Science
José Ávila-Mendoza, Janeth Mora, Martha Carranza, Maricela Luna, Carlos Arámburo
It is known that growth hormone (GH) is expressed in extrapituitary tissues, including the nervous system and ocular tissues, where it is involved in autocrine/paracrine actions related to cell survival and anti-apoptosis in several vertebrates. Little is known, however, in reptiles, so we analyzed the expression and distribution of GH in the eye of green iguana and its potential neuroprotective role in retinas that were damaged by the intraocular administration of kainic acid (KA). It was found, by Western blotting, that GH-immunoreactivity (GH-IR) was expressed as two isoforms (15 and 26kDa, under reducing conditions) in cornea, vitreous, retina, crystalline, iris and sclera, in varying proportions...
August 1, 2016: General and Comparative Endocrinology
Colin I Clement, Douglas G A Parker, Ivan Goldberg
Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics...
2016: Open Ophthalmology Journal
Sushma Tejwani, Sathi Devi, Shoruba Dinakaran, Rohit Shetty, Priti Meshram, Mathew Francis, Abhijit Sinha Roy
PURPOSE: To analyze the diagnostic efficacy of normalization of corneal deformation variables by the IOP in healthy, primary-angle closure (PACG), and primary open angle glaucoma (POAG) patients. METHODS: Fifty-nine healthy, 83 POAG, and 57 PACG eyes, matched for age and pachymetry, were included in a prospective, observational, cross-sectional study. Goldmann applanation tonometry (GAT-IOP), Corvis-ST IOP, IOPg (Goldmann correlated), and IOPcc (cornea compensated) from the ocular response analyzer were acquired...
March 2016: Investigative Ophthalmology & Visual Science
XiaoBo Zheng, FangJun Bao, Brendan Geraghty, JinHai Huang, Ayong Yu, QinMei Wang
BACKGROUD: To evaluate the symmetry of corneal biomechanical metrics, measured using an ocular response analyzer (ORA) and self-built corneal inflation test platform, in bilateral rabbit corneas and to investigate their relationship with physical intraocular pressure (IOPp). METHODS: Twenty fresh enucleated eyes from ten rabbits were used for ex vivo whole ocular globe inflation. IOP was increased from 7.5 to 37.5 mmHg with 7.5 mmHg steps and biomechanical metrics were acquired using the ORA...
2016: Eye and Vision (London, England)
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