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The Influence of Corneal Biomechanical Properties on Intraocular Pressure Measurements Using a Rebound Self-tonometer. J Glaucoma 2018; 27:511-518. [DOI: 10.1097/ijg.0000000000000948] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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102
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What We Have Learned From the Ocular Hypertension Treatment Study. Am J Ophthalmol 2018; 189:xxiv-xxvii. [PMID: 29501371 DOI: 10.1016/j.ajo.2018.02.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 02/22/2018] [Indexed: 11/23/2022]
Abstract
PURPOSE To identify results from the Ocular Hypertension Study that can aid patients and clinicians to make evidence-based decisions about the management of ocular hypertension. DESIGN Perspective. RESULTS At 60 months, the cumulative frequency of developing primary open-angle glaucoma (POAG) was 4.4% in the medication group and 9.5% in the observation group (hazard ratio for medication, 0.40; 95% confidence interval [CI], 0.27-0.59; P < .0001). At 13 years the cumulative proportion of participants who developed POAG was 0.22 (95% CI 0.19-0.25) in the original observation group and 0.16 (95% CI 0.13-0.19) in the original medication group (complementary log-log x2P = .009). A 5-factor model (older age, higher IOP, thinner central corneal thickness, larger cup-to-disc ratio, and higher visual field pattern standard deviation) separated participants at high and low risk of developing POAG. CONCLUSIONS Clinicians and patients can make evidence-based decisions about the management of ocular hypertension using the risk model and considering patient age, medical status, life expectancy, and personal preference.
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Abstract
PURPOSE To evaluate the thickness and depth of lamina cribrosa (LC) in the optic nerve head region of the eyes in patients with nonglaucomatous keratoconus and to compare the thickness and depth with those of age-matched controls. METHODS This was a cross-sectional, observational study comprising 45 patients with keratoconus and 56 healthy subjects. Analysis of LC imaging was performed using spectral domain optical coherence tomography. Data collected included spherical equivalent, central corneal thickness, axial length, intraocular pressure, and keratometry. RESULTS Eyes with keratoconus had significantly thinner LC (174.9 ± 11.4 vs. 249.1 ± 4.9 μm, P < 0.001) compared with control group eyes. There was no statistically significant difference in the depth of LC between the keratoconus and control groups (P = 0.3). Multivariable analysis, controlled for age and sex, showed that the thickness of LC significantly correlated with central corneal thickness (P < 0.001). This association persisted (P < 0.001) after controlling for intraocular pressure in addition to age and sex. There was no significant correlation with other factors, including the spherical equivalent (P = 0.93) and keratometry (P = 0.46). CONCLUSIONS The results of this study showed that optical coherence tomography measurement of LC revealed thinner LC for patients with keratoconus compared with healthy controls. The structural properties of the cornea may be related to the optic nerve.
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Mercer RN, Waring GO, Roberts CJ, Jhanji V, Wang Y, Filho JS, Hemings RA, Rocha KM. Comparison of Corneal Deformation Parameters in Keratoconic and Normal Eyes Using a Non-contact Tonometer With a Dynamic Ultra-High-Speed Scheimpflug Camera. J Refract Surg 2018; 33:625-631. [PMID: 28880338 DOI: 10.3928/1081597x-20170621-03] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 05/26/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate and compare biomechanical properties in normal and keratoconic eyes using a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany). METHODS This retrospective study evaluated 89 eyes (47 normal, 42 keratoconic) and a validation arm of 72 eyes (33 normal, 39 keratoconic) using the Corvis ST. A diagnosis of keratoconus was established by clinical findings confirmed by topography and tomography. Dynamic corneal response parameters collected by the Corvis ST (A1 velocity, deformation amplitude [DA], DA Ratio Max 1mm, and Max Inverse Radius) and a stiffness parameter at first applanation (SP-A1) were incorporated into a novel logistic regression equation (DCR index). Area under the receiver operating curve (AUC) was used to assess the sensitivity and specificity of the DCR index. RESULTS DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1 were each found to be statistically significantly different between normal and keratoconic eyes (Mann-Whitney test [independent samples]; P = .0077, < .0001, < .0001, and < .0001, respectively; significance level: P < .05). DCR index demonstrated high sensitivity, specificity, and overall correct detection rate (92.9%, 95.7%, and 94.4%, respectively; AUC = 98.5). The sensitivity and overall correct detection rate improved when eyes with Topographical Keratoconus Classification grades (TKC) greater than 0 were reevaluated (from 92.9% to 96.6% and from 94.4% to 96.1%, respectively). CONCLUSIONS Combining multiple biomechanical parameters (A1 velocity, DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1) into a logistic regression equation allows for high sensitivity and specificity for distinguishing keratoconic from normal eyes. [J Refract Surg. 2017;33(9):625-631.].
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105
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Chen M, Kueny L, Schwartz AL. The role of corneal hysteresis during the evaluation of patients with possible normal-tension glaucoma. Clin Ophthalmol 2018; 12:555-559. [PMID: 29606853 PMCID: PMC5868619 DOI: 10.2147/opth.s161675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose There are multiple reports of the role of corneal hysteresis (CH) as an independent risk factor for the diagnosis and risk of progression of normal-tension glaucoma (NTG). Our study measured CH with the Ocular Response Analyzer (ORA) in patients with intraocular pressure (IOP) <21 mmHg to investigate if a low CH would identify NTG in this Asian-based practice. Methods This was a prospective cross-sectional study of patients who underwent routine eye examination during 2016 in a private practice in Honolulu, Hawaii, where most patients are Asian. Inclusion criteria are: 1) ≥65 years 2) IOP <21 (compensated IOP by ORA), and 3) CH values <10 using ORA as measured by a single experienced technician. Exclusion criteria are: 1) sight-limiting ocular or corneal disease that would preclude accurate measurements for the purposes of the study. 2) Any patient who had difficulty in being tested with the ORA. 3) Patients who had any history of any type of glaucoma. All patients that met the inclusion criteria underwent fundus photography to measure cup-to-disc ratio and cup-to-disc asymmetry and also had central corneal thickness measured. Thickness of the retina nerve fiber layer was measured by ocular coherence tomography. The eyes with an average retina nerve fiber layer thickness less than 80 μm were classified as possible NTG and were scheduled for a visual field test. The field examination was considered valid only if the fixation, false positives, and false negatives were within the acceptable range. Patient demographics and data on preexisting diseases were collected including age, sex, coexisting medical conditions, and previous intraocular surgery. Those with thinning of retina nerve fiber layer on optical coherence tomography had a Humphrey visual field test to confirm the diagnosis of glaucoma. Results Seventy-six eyes of 46 patients that met the eligibility criteria were included in the study. Twenty-one previously undiagnosed eyes were confirmed as having NTG, which corresponds to an incidence of 27.6%. Conclusion CH measurement is a valuable test to assist in early diagnosis of NTG, especially in the elderly Asian population. With an established diagnosis, aggressive early treatments medically or surgically to further lower IOP can prevent irreversible blindness, which can severely impact the patient’s family and socioeconomic status.
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Affiliation(s)
- Ming Chen
- Department of Surgery, Division of Ophthalmology, University of Hawaii, Honolulu, HI, USA
| | - Laura Kueny
- Department of Ophthalmology, Georgetown University, Washington, DC, USA
| | - Arthur L Schwartz
- Department of Ophthalmology, Georgetown University, Washington, DC, USA
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106
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Gizzi C, Cellini M, Campos EC. In vivo assessment of changes in corneal hysteresis and lamina cribrosa position during acute intraocular pressure elevation in eyes with markedly asymmetrical glaucoma. Clin Ophthalmol 2018; 12:481-492. [PMID: 29588569 PMCID: PMC5858548 DOI: 10.2147/opth.s151532] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Purpose To investigate the biomechanical response of the cornea, lamina cribrosa (LC), and prelaminar tissue (PT) to an acute intraocular pressure (IOP) increase in patients with markedly asymmetrical glaucoma and in healthy controls. Patients and methods A total of 24 eyes of 12 patients with markedly asymmetrical primary open-angle glaucoma (POAG) and 12 eyes of 12 healthy patients were examined with spectral-domain optical coherence tomography (SD-OCT) and ocular response analyzer (ORA) at baseline and during acute IOP elevation by means of an ophthalmodynamometer. The displacement of the LC and PT and the change in corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated. Results Following a mean IOP increase of 12.3±2.4 mmHg, eyes with severe glaucoma demonstrated an overall mean anterior displacement of the LC (−6.58±26.09 µm) as opposed to the posterior laminar displacement in eyes with mild glaucoma (29.08±19.28 µm) and in healthy eyes (30.3±10.9; p≤0.001 and p=0.001, respectively). The PT displaced posteriorly during IOP elevation in all eyes. The CH decreased in eyes with severe glaucoma during IOP elevation (from 9.30±3.65 to 6.92±3.04 mmHg; p=0.012), whereas the CRF increased markedly in eyes with mild glaucoma (from 8.61±2.30 to 12.38±3.64; p=0.002) and in eyes with severe glaucoma (from 9.02±1.48 to 15.20±2.06; p=0.002). The increase in CRF correlated with the anterior displacement of the LC in eyes with severe glaucoma. Conclusion Eyes with severe glaucoma exhibited a mean overall anterior displacement of the anterior laminar surface, while eyes with mild glaucoma and healthy eyes showed a posterior displacement of the LC during IOP elevation. The CH decreased significantly from baseline only in eyes with severe glaucoma, but the CRF increased significantly in all glaucomatous eyes. The CRF increase correlated with the anterior displacement of the LC in eyes with severe glaucoma.
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Affiliation(s)
- Corrado Gizzi
- Department of Experimental, Diagnostic and Speciality Medicine, Ophthalmology Service, University of Bologna, Bologna, Italy
| | - Mauro Cellini
- Department of Experimental, Diagnostic and Speciality Medicine, Ophthalmology Service, University of Bologna, Bologna, Italy
| | - Emilio C Campos
- Department of Experimental, Diagnostic and Speciality Medicine, Ophthalmology Service, University of Bologna, Bologna, Italy
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Susanna CN, Diniz-Filho A, Daga FB, Susanna BN, Zhu F, Ogata NG, Medeiros FA. A Prospective Longitudinal Study to Investigate Corneal Hysteresis as a Risk Factor for Predicting Development of Glaucoma. Am J Ophthalmol 2018; 187:148-152. [PMID: 29305310 DOI: 10.1016/j.ajo.2017.12.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/10/2017] [Accepted: 12/19/2017] [Indexed: 11/17/2022]
Abstract
PURPOSE To investigate the role of corneal hysteresis (CH) as a risk factor for development of glaucoma. DESIGN Prospective observational cohort study. METHODS Two hundred and eighty-seven eyes of 199 patients suspected of having glaucoma were followed for an average of 3.9 ± 1.8 years. All eyes had normal visual fields at baseline. Development of glaucoma was defined as occurrence of 3 consecutive abnormal standard automated perimetry tests during follow-up, defined as pattern standard deviation (PSD) < 5%, and/or Glaucoma Hemifield Test outside normal limits. Measurements of CH were acquired at baseline using the Ocular Response Analyzer (ORA). Univariable and multivariable Cox regression models were used to investigate baseline factors associated with development of visual field loss over time. RESULTS Fifty-four (19%) eyes developed repeatable visual field defects during follow-up. Measurements of CH at baseline were significantly lower in patients who developed glaucoma vs those who did not (9.5 ± 1.5 mm Hg vs 10.2 ± 2.0 mm Hg; P = .012). Each 1-mm Hg lower CH was associated with an increase of 21% in the risk of developing glaucoma during follow-up (95% confidence interval [CI]: 1.04-1.41; P = .013). In a multivariable model adjusting for age, intraocular pressure, central corneal thickness, PSD, and treatment, CH was still predictive of development of glaucoma (hazard ratio = 1.20; 95% CI: 1.01-1.42; P = .040). CONCLUSION Baseline lower CH measurements were significantly associated with increased risk of developing glaucomatous visual field defects over time. The prospective longitudinal design of this study supports a role of CH as a risk factor for developing glaucoma.
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Affiliation(s)
- Carolina N Susanna
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina; Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Alberto Diniz-Filho
- Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Fábio B Daga
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina
| | - Bianca N Susanna
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina; Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Feilin Zhu
- Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Nara G Ogata
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina
| | - Felipe A Medeiros
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina; Department of Ophthalmology, University of California San Diego, La Jolla, California.
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108
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Aoki S, Murata H, Matsuura M, Fujino Y, Nakakura S, Nakao Y, Kiuchi Y, Asaoka R. The effect of air pulse-driven whole eye motion on the association between corneal hysteresis and glaucomatous visual field progression. Sci Rep 2018; 8:2969. [PMID: 29445204 PMCID: PMC5813173 DOI: 10.1038/s41598-018-21424-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/05/2018] [Indexed: 11/30/2022] Open
Abstract
Corneal hysteresis (CH) measured with Ocular Response Analyzer (Reichert: ORA) has been reported to be closely related to the glaucomatous visual field (VF) progression. The air pulse applied to an eye not only induces corneal deformation, but also whole eye motion (WEM), which may result in an inaccurate measurement of CH. Here we investigated the influence of air pulse-driven WEM measured with the Corivs ST (CST®, OCULUS) on the relationship between CH and VF progression in primary open angle-glaucoma patients. Using the CST parameters of the maximal WEM displacement (WEM-d) and the time to reach that displacement (WEM-t), the eyes were classified into subgroups (WEM-d low- and high-group, and WEM-t short- and long-group). For the whole population and all subgroups, the optimal linear mixed model to describe mean of total deviation (mTD) progression rate with eight reliable VFs was selected from all combinations of seven parameters including CH. As a result, optimal models for the mTD progression rate included CH in the whole population, the WEM-d low- group and the WEM-t short-group, but not in the WEM-d high-group and the WEM-t long-group. Our findings indicated association between CH and glaucomatous progression can be weakened because of large WEM.
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Affiliation(s)
- Shuichiro Aoki
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Murata
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Masato Matsuura
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan.,Department of Rehabilitation, Orthopic and Visual Science, School of Allied Health Sciences, Kitasato University, Tokyo, Kanagawa, Japan
| | - Yuri Fujino
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Shunsuke Nakakura
- Department of Ophthalmology, Saneikai Tsukazaki Hospital, Himeji, Japan
| | - Yoshitaka Nakao
- Department of Ophthalmology and Visual Sciences, Hiroshima University, Higashihiroshima, Japan
| | - Yoshiaki Kiuchi
- Department of Ophthalmology and Visual Sciences, Hiroshima University, Higashihiroshima, Japan
| | - Ryo Asaoka
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan.
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109
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Corneal Vibrations during Intraocular Pressure Measurement with an Air-Puff Method. JOURNAL OF HEALTHCARE ENGINEERING 2018; 2018:5705749. [PMID: 29610655 PMCID: PMC5828335 DOI: 10.1155/2018/5705749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/25/2017] [Accepted: 12/11/2017] [Indexed: 12/19/2022]
Abstract
Introduction The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis. The presented definition and measurement method allow for the analysis of image sequences of eye responses—cornea deformation. In particular, the outer corneal contour and sclera fragments are analysed, and 3D reconstruction is performed. Methods On this basis, well-known parameters such as eyeball reaction or corneal response are determined. The next steps of analysis allow for automatic and reproducible separation of four different corneal vibrations. These vibrations are associated with (1) the location of the maximum of cornea deformation; (2) the cutoff area measured in relation to the cornea in a steady state; (3) the maximum of peaks occurring between applanations; and (4) the other characteristic points of the corneal contour. Results The results obtained enable (1) automatic determination of the amplitude of vibrations; (2) determination of the frequency of vibrations; and (3) determination of the correlation between the selected types of vibrations. Conclusions These are diagnostic features that can be directly applied clinically for new and archived data.
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110
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Pavlatos E, Chen H, Clayson K, Pan X, Liu J. Imaging Corneal Biomechanical Responses to Ocular Pulse Using High-Frequency Ultrasound. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:663-670. [PMID: 29408793 PMCID: PMC5826553 DOI: 10.1109/tmi.2017.2775146] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Imaging corneal biomechanical changes or abnormalities is important for better clinical diagnosis and treatment of corneal diseases. We propose a novel ultrasound-based method, called ocular pulse elastography (OPE), to image corneal deformation during the naturally occurring ocular pulse. Experiments on animal and human donor eyes, as well as synthetic radiofrequency (RF) data, were used to evaluate the efficacy of the OPE method. Using very high-frequency ultrasound (center frequency = 55 MHz), correlation-based speckle tracking yielded an accuracy of less than 10% error for axial tissue displacements of or above. Satisfactory speckle tracking was achieved for out-of-plane displacements up to . Using synthetic RF data with or without a pre-defined uniform strain, the OPE method detected strains down to 0.0001 axially and 0.00025 laterally with an error less than 10%. Experiments in human donor eyes showed excellent repeatability with an intraclass correlation of 0.98. The measurement outcome from OPE was also shown to be highly correlated with that of standard inflation. These results suggest the feasibility of OPE as a potential clinical tool for evaluating corneal biomechanics in vivo.
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111
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Relationship between corneal biomechanical properties and structural biomarkers in patients with normal-tension glaucoma: a retrospective study. BMC Ophthalmol 2018; 18:7. [PMID: 29334923 PMCID: PMC5769305 DOI: 10.1186/s12886-018-0673-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 01/04/2018] [Indexed: 11/10/2022] Open
Abstract
Background We evaluated the relationships between corneal biomechanical properties and structural parameters in patients with newly diagnosed, untreated normal-tension glaucoma (NTG). Methods All subjects were evaluated using an Ocular Response Analyzer (ORA) measuring corneal hysteresis (CH) and the corneal resistance factor (CRF). Central corneal thickness (CCT), Goldmann applanation tonometric (GAT) data, axial length, and the spherical equivalent (SE), were also measured. Confocal scanning laser ophthalmoscopy was performed with the aid of a Heidelberg retina tomograph (HRT III). We sought correlations between HRT parameters and different variables including CCT, CH, and the CRF. Multiple linear regression analysis was performed to identify significant associations between corneal biomechanical properties and optic nerve head parameters. Results We enrolled 95 eyes of 95 NTG patients and 93 eyes of 93 normal subjects. CH and the CRF were significantly lower in more advanced glaucomatous eyes (P = 0.001, P = 0.008, respectively). The rim area, rim volume, linear cup-to-disc ratio (LCDR), and mean retinal nerve fiber layer (RNFL) thickness were significantly worse in more advanced glaucomatous eyes (P < 0.001, P < 0.001, P < 0.001, and P = 0.001). CH was directly associated with rim area, rim volume, and mean RNFL thickness (P = 0.012, P = 0.028, and P = 0.043) and inversely associated with LCDR (P = 0.015), after adjusting for age, axial length, CCT, disc area, GAT data, and SE. However, in normal subjects, there were no significant associations between corneal biomechanical properties and HRT parameters. Conclusions A lower CH is significantly associated with a smaller rim area and volume, a thinner RNFL, and a larger LCDR, independent of disc size, corneal thickness, intraocular pressure, and age.
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112
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Hussnain SA, Kovacs KD, Warren JL, Teng CC. Corneal hysteresis and anterior segment optical coherence tomography anatomical parameters in primary angle closure suspects. Clin Exp Ophthalmol 2018; 46:468-472. [PMID: 29251401 DOI: 10.1111/ceo.13135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/20/2017] [Accepted: 12/05/2017] [Indexed: 11/29/2022]
Abstract
IMPORTANCE Corneal hysteresis (CH) is a dynamic marker of structural and functional changes in the cornea associated with intraocular pressure (IOP) and central corneal thickness, but its utility in assessing primary angle closure suspects (PACS) has not been fully elucidated. BACKGROUND This study assesses if anterior segment measurements correlate with CH in PACS patients. DESIGN IRB-approved retrospective review of imaging and records at a university practice. PARTICIPANTS Sixty-three eyes from 37 patients diagnosed as PACS, without other ocular pathology. METHODS Every eye underwent measurements including: ocular response analyzer (ORA), anterior segment optical coherence tomography (OCT) and a clinical evaluation. ORA measurements were correlated with other anatomic parameters using a mixed effects multivariable linear regression framework. MAIN OUTCOME MEASURES ORA measurements included: CH, corneal resistance factor, Goldmann IOP (IOPg ) and corneal compensated IOP (IOPcc ). Anterior segment OCT measurements included: central corneal thickness (CCTOCT ), nasal and temporal peripheral corneal thicknesses (PCT1 and PCT2), anterior chamber depth (ACD), nasal angle to temporal angle distance (ATA) and temporal and nasal angle measurements. Clinical measurements included: central corneal thickness via pachymetry, IOP measured by Goldmann applanation, axial length by A-scan ultrasound and spherical equivalent. RESULTS CH was negatively correlated with IOPcc, and ACD CH was positively correlated with CCTOCT , CCTp , CRF, PCT1 and PCT2. Females were found to have lower CH. In multivariable regression controlling for gender, CCT, PCT, IOP and ACD, no correlation was seen between CH and anatomic measurements. CONCLUSIONS AND RELEVANCE CH values in PACS do not correlate with anterior segment anatomy.
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Affiliation(s)
- Syed Amal Hussnain
- Department of Ophthalmology and Visual Science, Yale School of Medicine, New Haven, Connecticut, USA
| | - Kyle D Kovacs
- Department of Ophthalmology and Visual Science, Yale School of Medicine, New Haven, Connecticut, USA
| | - Joshua L Warren
- Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA
| | - Christopher C Teng
- Department of Ophthalmology and Visual Science, Yale School of Medicine, New Haven, Connecticut, USA
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113
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McCafferty S, Levine J, Schwiegerling J, Enikov ET. Goldmann and error correcting tonometry prisms compared to intracameral pressure. BMC Ophthalmol 2018; 18:2. [PMID: 29301514 PMCID: PMC5753488 DOI: 10.1186/s12886-017-0668-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 12/13/2017] [Indexed: 11/14/2022] Open
Abstract
Background Compare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro. Methods Pressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures. Statistical comparison was made between true intracameral pressures and the two prism measurements. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF). Human cadaver eyes were used to assess measurement repeatability. Results The CATS tonometer prism measured closer to true intracameral IOP than the GAT prism by 1.7+/−2.7 mmHg across all pressures and corneal properties. The difference in CATS and GAT measurements was greater in thin CCT corneas (2.7+/−1.9 mmHg) and low resistance (CRF) corneas (2.8+/−2.1 mmHg). The difference in prisms was negligible at high CCT and CRF values. No difference was seen in measurement repeatability between the two prisms. Conclusion A CATS prism in Goldmann tonometer armatures significantly improve the accuracy of IOP measurement compared to true intracameral pressure across a physiologic range of IOP values. The CATS prism is significantly more accurate compared to the GAT prism in thin and less rigid corneas. The in vivo intracameral study validates mathematical models and clinical findings in IOP measurement between the GAT and CATS prisms.
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Affiliation(s)
- Sean McCafferty
- Department of Ophthalmology, Intuor Technologies, University of Arizona- College of Medicine, University of Arizona- College of Optical Science, LLC 6422 E. Speedway Blvd. Suite 100, Tucson, AZ, 85710, USA. .,Department of Ophthalmology, University of Arizona- College of Medicine, 6422 E. Speedway Blvd. Suite 100, Tucson, AZ, 85710, USA. .,Department of Aerospace and Mechanical, University of Arizona-College of Engineering, 1130 N. Mountain Ave, Tucson, AZ, 85721, USA. .,, Tucson, USA.
| | - Jason Levine
- Department of Ophthalmology, University of Arizona- College of Medicine, 6422 E. Speedway Blvd. Suite 100, Tucson, AZ, 85710, USA.,, Tucson, USA
| | - Jim Schwiegerling
- Department of Ophthalmology, University of Arizona- College of Medicine, 6422 E. Speedway Blvd. Suite 100, Tucson, AZ, 85710, USA.,Department of Aerospace and Mechanical, University of Arizona-College of Engineering, 1130 N. Mountain Ave, Tucson, AZ, 85721, USA
| | - Eniko T Enikov
- Department of Ophthalmology, University of Arizona-College of Optical Science, University of Arizona-College of Medicine, 1630 E. University Blvd, Tucson, AZ, 85719, USA
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114
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The Relationship between the Waveform Parameters from the Ocular Response Analyzer and the Progression of Glaucoma. Ophthalmol Glaucoma 2018; 1:123-131. [PMID: 32672562 DOI: 10.1016/j.ogla.2018.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 08/14/2018] [Accepted: 08/17/2018] [Indexed: 11/23/2022]
Abstract
PURPOSE To investigate the usefulness of waveform parameters measured with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY) in assessing the progression of glaucomatous visual field (VF). DESIGN Observational cross-sectional study. PARTICIPANTS One hundred and one eyes with primary open-angle glaucoma in 68 patients with 8 reliable VFs using the Humphrey Field Analyzer (Carl Zeiss Meditec, Inc., Dublin, CA). METHODS The mean of total deviation (mTD) value of the 52 test points in the 24-2 Humphrey Field Analyzer VF test pattern was calculated, and the progression rate of mTD was determined using 8 VFs. Ocular Response Analyzer measurement was performed 3 times in the same day, and the average values of the 3 measurements were used in the analysis. Then, the optimal linear mixed model was selected using 7 parameters: age, mean and standard deviation of intraocular pressure with the Goldmann applanation tonometry during the observation period, central corneal thickness, axial length, mTD in the initial VF, and corneal hysteresis (CH) other than waveform parameters, henceforth known as the basic model. In addition, using the 37 waveform parameters, the optimal model for the mTD progression rate was identified, according to the second-order bias-corrected Akaike information criterion (AICc) index, using 15 preselected waveform parameters with the least absolute shrinkage and selection operator regression (henceforth known as the waveform model). MAIN OUTCOME MEASURES Optimal linear mixed models for the mTD progression rate, as determined by AICc index. RESULTS The mean ± standard deviation mTD progression rate was -0.25±0.31 dB/year. The basic model was mTD progression rate = -0.94 + 0.075 × CH (AICc = 46.71). The waveform model was mTD progression rate = 1.25 - 0.066 × path2 - 0.000099 × p2area + 0.0021 × mslew2 (AICc = 44.95). The relative likelihood of the latter model being the optimal model was 6.23 times greater than that of the former model. CONCLUSIONS Ocular Response Analyzer waveform parameters were correlated significantly with glaucomatous VF progression and showed a stronger than correlation with VF progression than CH.
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Corneal Biomechanical Properties and Central Corneal Thickness in Pediatric Noninfectious Uveitis: A Controlled Study. Eye Contact Lens 2017; 44 Suppl 2:S60-S64. [PMID: 29283900 DOI: 10.1097/icl.0000000000000465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To compare the corneal biomechanics, intraocular pressure (IOP), and central corneal thickness (CCT) of 37 patients with pediatric noninfectious uveitis with 36 healthy children. METHODS Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated and corneal-compensated IOP (IOPg and IOPcc, respectively), and CCT were measured. RESULTS The mean CRF was significantly lower in the pediatric uveitic eyes than controls (9.7±1.9 vs. 10.8±1.5 mm Hg, P=0.009), whereas there was no significant difference for mean CH, IOPg, IOPcc, and CCT between the two groups (10.1±1.9 vs. 10.8±1.7, 12.9±3.3 vs. 13.9±3.1, 13.8±2.8 vs. 13.6±3.2 mm Hg, and 550.7±49.5 vs. 555.1±33.5 μm, respectively, all P>0.05). The CCT values correlated with CH and CRF, with a Pearson correlation of 0.511 and 0.670 (P=0.013 and P<0.001, respectively), whereas disease duration did not correlate with any corneal biomechanics or CCT in pediatric uveitic eyes (all P>0.05). CONCLUSIONS Pediatric noninfectious uveitic eyes have lower CRF than controls but the CH, IOPg, IOPcc, and CCT values are similar.
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Reproducibility of Central Corneal Thickness Measurements in Healthy and Glaucomatous Eyes. J Glaucoma 2017; 26:787-791. [PMID: 28816818 DOI: 10.1097/ijg.0000000000000738] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE The purpose of this study is to characterize intraday and interday variation in central corneal thickness (CCT) in healthy and glaucomatous subjects. METHODS In this prospective cohort study, 40 healthy subjects and 42 subjects with primary open-angle glaucoma underwent CCT measurements by ultrasonic pachymetry on 5 days over 1 year: first at baseline, then at 1 week and 1, 6, and 12 months after baseline. On 1visit, CCT was measured every 2 hours from 08:00 to 20:00. Intraday CCT variance was compared with interday CCT variance. RESULTS Mean CCT at all visits and time points ranged from 561 to 574 µm in healthy eyes and from 548 to 563 µm in glaucomatous eyes. The mean intraday CCT range (highest minus lowest readings) was 21±10 µm in healthy participants and 21±10 µm in glaucoma patients. The mean interday CCT range was 27±13 µm in healthy participants and 24±14 µm in glaucoma patients. Within-subject variance was significantly larger among the interday CCT measurements than the intraday CCT measurements in both healthy subjects and glaucoma patients (P<0.0001 for both) demonstrating that measurements taken on separate days are more different than measurements taken on the same day. Interday CCT differences of ≥30 µm were seen in 27.7% of normal subjects and 30% of glaucoma patients. CONCLUSIONS CCT measurements exhibit intraday and interday variation, with the latter being significantly greater than the former. A single CCT assessment inadequately characterizes CCT and may impact risk assessment in patients with suspect and/or diagnosed glaucoma.
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McCafferty S, Levine J, Schwiegerling J, Enikov ET. Goldmann applanation tonometry error relative to true intracameral intraocular pressure in vitro and in vivo. BMC Ophthalmol 2017; 17:215. [PMID: 29178849 PMCID: PMC5702103 DOI: 10.1186/s12886-017-0608-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 11/16/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Goldmann applanation tonometry (GAT) error relative to intracameral intraocular pressure (IOP) has not been examined comparatively in both human cadaver eyes and in live human eyes. Futhermore, correlations to biomechanical corneal properties and positional changes have not been examined directly to intracameral IOP and GAT IOP. METHODS Intracameral IOP was measured via pressure transducer on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically on each patient alternately to 10, 20, and 40 mmHg. IOP was measured using a Perkins tonometer in the supine position on 58 eyes and upright on a subset of 8 eyes. Twenty one (21) fresh human cadaver globes were Intracamerally IOP adjusted and measured via pressure transducer. Intracameral IOP ranged between 5 and 60 mmHg. IOP was measured in the upright position with a Goldmann Applanation Tonometer (GAT) and supine position with a Perkins tonometer. Central corneal thickness (CCT) was also measured. RESULTS The Goldmann-type tonometer error measured on live human eyes was 5.2 +/-1.6 mmHg lower than intracameral IOP in the upright position and 7.9 +/- 2.3 mmHg lower in the supine position (p < .05). CCT also indicated a sloped correlation to error (correlation coeff. = 0.18). Cadaver eye IOP measurements were 3.1+/-2.5 mmHg lower than intracameral IOP in the upright position and 5.4+/- 3.1 mmHg in the supine position (p < .05). CONCLUSION Goldmann IOP measures significantly lower than true intracameral IOP by approximately 3 mmHg in vitro and 5 mmHg in vivo. The Goldmann IOP error is increased an additional 2.8 mmHg lower in the supine position. CCT appears to significantly affect the error by up to 4 mmHg over the sample size.
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Affiliation(s)
- Sean McCafferty
- Intuor Technolgies, LLC, 6422 E. Speedway Blvd. Tucson, Suite 100, Tucson, AZ, 85710, USA. .,Department of Ophthalmology, University of Arizona College of Medicine, 655 n alvernon, Tucson, AZ, 85710, USA. .,University of Arizona College of Optical Science, 1630 E. University Blvd., Tucson, AZ, 85719, USA. .,Arizona Eye Consultants, 6422 E. Speedway Blvd. Tucson, Suite 100, Tucson, AZ, 85710, USA.
| | - Jason Levine
- Department of Ophthalmology, University of Arizona College of Medicine, 655 n alvernon, Tucson, AZ, 85710, USA.,Arizona Eye Consultants, 6422 E. Speedway Blvd. Tucson, Suite 100, Tucson, AZ, 85710, USA
| | - Jim Schwiegerling
- Department of Ophthalmology, University of Arizona College of Medicine, 655 n alvernon, Tucson, AZ, 85710, USA.,University of Arizona College of Optical Science, 1630 E. University Blvd., Tucson, AZ, 85719, USA
| | - Eniko T Enikov
- Department of Mechanical and Aerospace, University of Arizona College of Engineering, 1130 N. Mountain Ave., Tucson, AZ, 85721, USA
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Evaluation of Corneal Deformation Parameters Provided by the Corvis ST Tonometer After Trabeculectomy. J Glaucoma 2017; 26:166-172. [PMID: 27875486 DOI: 10.1097/ijg.0000000000000590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aims of this study were to evaluate how the corneal deformation parameters provided by the Corvis ST tonometer (CST) were influenced by pressure-lowering ocular surgery, and to determine the correlations of intraocular pressure (IOP) and axial length (AL) with CST corneal deformation parameters. METHODS This prospective 1-month study enrolled 22 subjects (22 eyes) who underwent trabeculectomy combined with mitomycin C. The corneal deformation parameters were measured using the CST. IOP was measured before and after surgery by a Goldmann applanation tonometer and the CST. The central corneal thickness and AL were also recorded. The correlations of the corneal deformation parameters with central corneal thickness, AL, and IOP changes were determined by linear regression analysis. RESULTS IOP decreased significantly after surgery. AL was significantly shorter at 1 week after surgery. There were significant changes in the CST parameters time 1, velocity 1, velocity 2, peak distance highest concavity, and deformation amplitude highest concavity at 1 week and 1 month after surgery and in time highest concavity at 1 week after surgery. The change in time 1 was significantly correlated with preoperative IOP and the IOP reductions, and was positively correlated with the decrease in AL at 1 week. The increase in velocity 1 was negatively correlated with preoperative IOP, and IOP reductions. The change in time highest concavity was negatively correlated with IOP before surgery and the decrease in IOP at 1 week. CONCLUSION CST is a good choice for measuring IOP, especially when aiming for normalization of IOP after glaucoma surgery.
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Jung Y, Park HYL, Yang HJ, Park CK. Characteristics of corneal biomechanical responses detected by a non-contact scheimpflug-based tonometer in eyes with glaucoma. Acta Ophthalmol 2017. [PMID: 28636261 DOI: 10.1111/aos.13466] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
PURPOSE To determine the corneal biomechanical properties in eyes with glaucoma using a non-contact Scheimpflug-based tonometer. METHODS Corneal biomechanical responses were examined using a non-contact Scheimpflug-based tonometer. The tonometer parameters of the normal control group (n = 75) were compared with those of the glaucoma group (n = 136), including an analysis of glaucoma subgroups categorized by visual field loss. RESULTS After adjusting for potential confounding factors, including the intraocular pressure (IOP), central corneal thickness (CCT), age and axial length, the deformation amplitude was smaller in the glaucoma group (1.09 ± 0.02 mm) than in the normal control group (1.12 ± 0.02 mm; p value = 0.031). The deformation amplitude and the deflection amplitude of the severe glaucoma group (1.12 ± 0.02 mm and 0.92 ± 0.01 mm) were significantly greater than that of the early glaucoma group (1.07 ± 0.01 mm and 0.88 ± 0.11 mm, p = 0.006 and p = 0.031), whereas that of the moderate glaucoma group (1.09 ± 0.02 mm and 0.90 ± 0.02 mm) was greater than that of the early glaucoma group, but this difference was not statistically significant. The deformation amplitude showed a negative correlation with the CCT in the normal control group (r = -0.235), with a weaker negative relationship observed in the early glaucoma group (r = -0.099). However, in the moderate and severe glaucoma groups, the deformation amplitude showed a positive relationship with the CCT, showing an inverse relationship. The duration and number of antiglaucomatous eyedrops used had negative correlations with the CCT in eyes with moderate and severe glaucoma. CONCLUSION Overall, the glaucoma group showed significantly less deformable corneas than did the normal controls, even after adjusting for the IOP, CCT, age and axial length. However, there were also differences according to the severity of glaucoma, where the corneal deformation amplitude was greater in the severe glaucoma group compared to the early glaucoma group. The combined effects of stiffening due to glaucoma and increased viscoelastic properties caused by the chronic use of antiglaucomatous eyedrops may have resulted in the present findings.
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Affiliation(s)
- Younhea Jung
- Department of Ophthalmology and Visual Science; College of Medicine; Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - Hae-Young L. Park
- Department of Ophthalmology and Visual Science; College of Medicine; Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - Hee Jung Yang
- Department of Ophthalmology and Visual Science; College of Medicine; Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - Chan Kee Park
- Department of Ophthalmology and Visual Science; College of Medicine; Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
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Chansangpetch S, Panpruk R, Manassakorn A, Tantisevi V, Rojanapongpun P, Hurst CP, Lin SC. Impact of Myopia on Corneal Biomechanics in Glaucoma and Nonglaucoma Patients. Invest Ophthalmol Vis Sci 2017; 58:4990-4996. [PMID: 28979996 PMCID: PMC5627793 DOI: 10.1167/iovs.17-22219] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Purpose We evaluated the impact of myopia on corneal biomechanical properties in primary open-angle glaucoma (POAG) and nonglaucoma patients, and the effect of modification of glaucoma on myopic eyes. Methods This cross-sectional study included 66 POAG eyes (33 myopia, 33 nonmyopia) and 66 normal eyes (33 myopia, 33 nonmyopia). Seven corneal biomechanical parameters were measured by ultra-high-speed Scheimpflug imaging, including corneal deformation amplitude (CDA), inward/outward corneal applanation length (ICA, OCA), inward/outward corneal velocity (ICV, OCV), radius, and peak distance (PD). Results Mean age (SD) of the 65 male (49%) and 67 female (51%) patients was 59 (9.82) years. Myopia was associated with significantly higher CDA (adjusted effect = 0.104, P = 0.001) and lower OCV (adjusted effect = -0.105, P < 0.001) in the POAG group. Within the nonglaucoma group, myopic eyes had a significantly lower OCV (adjusted effect = -0.086, P < 0.001) and higher CDA (adjusted effect = 0.079, P = 0.001). All parameters except PD suggested that glaucoma modified the effect of myopia on corneal biomechanics. Percentage differences in the adjusted myopic effect between POAG and nonglaucoma patients was 31.65, 27.27, 31.65, 50.00, 22.09, and 60.49 for CDA, ICA, OCA, ICV, OCV, and radius, respectively. Conclusions Myopia had a significant impact on corneal biomechanical properties in the POAG and nonglaucoma groups. The differences in corneal biomechanical parameters suggest that myopia is correlated with significantly lower ocular rigidity. POAG may enhance the effects of myopia on most of these parameters.
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Affiliation(s)
- Sunee Chansangpetch
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.,Department of Ophthalmology, University of California, San Francisco Medical School, San Francisco, California, United States
| | - Rawiphan Panpruk
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Anita Manassakorn
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Visanee Tantisevi
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Prin Rojanapongpun
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Cameron P Hurst
- Biostatistics Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Shan C Lin
- Department of Ophthalmology, University of California, San Francisco Medical School, San Francisco, California, United States
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Lee EJ, Han JC, Kee C. Intereye comparison of ocular factors in normal tension glaucoma with asymmetric visual field loss in Korean population. PLoS One 2017; 12:e0186236. [PMID: 29040292 PMCID: PMC5645097 DOI: 10.1371/journal.pone.0186236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 09/27/2017] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To identify ocular parameters corresponding to asymmetric visual field (VF) loss in normal tension glaucoma (NTG) through intereye comparisons. PATIENTS AND METHODS Medical records of NTG patients with asymmetric and symmetric VF losses were retrospectively reviewed. The criterion for asymmetry in VF was 6 dB difference of mean deviation. Refractive error, intraocular pressure (IOP), central corneal thickness, ovality index, and peripapillary atrophy (PPA)/disc area ratio were obtained from each patient. Intereye comparison was performed for asymmetric group, symmetric group, and myopic and nonmyopic asymmetric subgroups. RESULTS We included 155 patients; 110 patients in asymmetric group and 45 patients in symmetric group. In intereye comparison for total asymmetric group, refractive error (P = 0.006), initial IOP (P = 0.001), ovality index (P = 0.008), and PPA (P < 0.001) were significantly asymmetric. For myopic subgroup, refractive error (P = 0.004), ovality index (P = 0.001), and PPA (P = 0.003) were significant factors. For nonmyopic subgroup, initial IOP (P = 0.003) and PPA (P = 0.007) were significant factors. Symmetric group showed no significant difference between the eyes. Multivariate analysis demonstrated that refractive error (P = 0.002) and PPA (P = 0.028) were significant factors in myopic subgroup, and initial IOP (P = 0.022) and PPA (P = 0.002) were significant factors in nonmyopic subgroup. CONCLUSIONS In this intereye comparison, the more myopic eye in myopic NTG patient, and the more pressured eye in nonmyopic NTG patient demonstrated more severe VF loss. Myopic and nonmyopic patients may follow different pathophysiologic processes. Discriminative attentions should be paid to NTG patients by subtypes.
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Affiliation(s)
- Eun Jung Lee
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jong Chul Han
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Changwon Kee
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Makashova NV, Vasilyeva AE. [Changes in biomechanical properties of the ocular fibrous tunic in patients with primary open-angle glaucoma in response to drug-induced stress-relief tests]. Vestn Oftalmol 2017; 133:31-36. [PMID: 28980563 DOI: 10.17116/oftalma2017133431-36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM To determine the effect of drug-induced stress-relief tests on biomechanical properties of the ocular fibrous tunic in eyes with early, moderate, or advanced primary open-angle glaucoma (POAG). MATERIAL AND METHODS A total of 202 eyes of 150 patients with POAG of different severity (early, moderate, or advanced) and 36 eyes of 30 healthy controls were examined. The mean patient age was 62±8.2 years. All groups were standardized by age, sex, and the range of corneal-compensated intraocular pressure (IOP) at baseline (21-30 mmHg). All patients underwent a standard ophthalmic examination, including visometry, biomicroscopy, gonioscopy, ophthalmoscopy, and Humphrey visual field assessment. Corneal hysteresis (CH), corneal resistance factor (CRF), CH-CRF difference, corneal-compensated IOP (IOPcc), and Goldmann-related IOP (IOPg) were measured with Ocular Response Analyzer (ORA, Reichert, USA). The axial eye length was measured on an ultrasonic A-scan (Ocuscan RxP, Alcon, USA) in the 10 MHz mode. RESULTS CH and CRF variability analysis was conducted to assess changes in biomechanical properties of the fibrous tunic due to an IOP decrease and a tendency toward compensation. For the first time, the ratio between CH and CRF changes (ΔCH/ΔCRF) was used to evaluate biomechanical properties of the fibrous tunic. This ratio provides understanding of the significance of CH and CRF changes after reduction of IOP. In early glaucoma patients, it differed inconsiderably from the control group (p>0.05) and averaged 1.62±0.9. In moderate glaucoma, CH changes were more pronounced than those of CRF: ΔCH/ΔCRF - 2.03±2.41 (under conservative treatment) and 2.12±1.07 (without treatment). In advanced glaucoma an opposite pattern was observed: the CH/CRF ratio got closer to 1.0 largely due to CRF changes, while CH changes became much less pronounced (or even negative, in some cases): ΔCH/ΔCRF - 0.27±0.32 (under conservative treatment), 0.16±1.29 (without treatment). CONCLUSION While the IOP decreased as a result of drug-induced stress-relief tests, CH and CRF changes differed between the groups depending on the stage of POAG. In early and moderate glaucoma, CH undergoes greater changes than CRF. In advanced glaucoma, CRF changes are more pronounced, and, hence, the ΔCH/ΔCRF ratio shifts reliably as glaucoma progresses. The ratio has also been shown to depend on the duration of the disease and on whether or not eye drops were prescribed.
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Affiliation(s)
- N V Makashova
- Research Institute of Eye Diseases, 11 A,B Rossolimo St., Moscow, Russia, 119021
| | - A E Vasilyeva
- I.M. Sechenov First Moscow State Medical University, 8/2 Trubetskaya St., Moscow, Russia, 119991
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Miki A, Maeda N, Asai T, Ikuno Y, Nishida K. Measurement repeatability of the dynamic Scheimpflug analyzer. Jpn J Ophthalmol 2017; 61:433-440. [PMID: 28983780 DOI: 10.1007/s10384-017-0534-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 07/28/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE To evaluate the repeatability of corneal deformation parameters measured using a dynamic Scheimpflug analyzer and the impact of baseline clinical factors on the repeatability of each parameter. STUDY DESIGN Retrospective, cross-sectional study. METHODS Forty-eight eyes (48 healthy subjects; mean age, 49.0 ± 19.5 years) underwent repeated examinations with the Scheimpflug analyzer to evaluate the test-retest variability. The intraclass correlation coefficient (ICC) and repeatability coefficient as indicators of variability were computed for 35 parameters measured with the Scheimpflug analyzer. The associations between the magnitude of the test-retest variability and baseline factors, such as age, axial length (AL), intraocular pressure (IOP), and central corneal thickness (CCT), were analyzed. RESULTS The test-retest repeatability was excellent for 22 (62.9%) of 35 parameters (ICC ≥ 0.75), good for seven (20%), (ICC ≥ 0.6), fair for four (11.4%), (ICC ≥ 0.4), and poor for two (5.7%) parameters (ICC < 0.4). Age was associated positively with the magnitude of variability in 13 (37.1%) parameters; measurement variability was affected significantly by AL (5 parameters, 14.3%) and CCT (7 parameters, 20%) but, except for one parameter not by IOP. CONCLUSION Most parameters of the dynamic Scheimpflug analyzer showed favorable measurement reliability in healthy subjects. However, six parameters showed poor-to-fair repeatability. Age, AL, and CCT significantly affected the repeatability of several parameters. These results should be considered when clinicians use this device in clinical practice.
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Affiliation(s)
- Atsuya Miki
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan.
| | - Naoyuki Maeda
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Tomoko Asai
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Yasushi Ikuno
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
| | - Kohji Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita, Osaka, 565-0871, Japan
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Corneal Biomechanical Changes After Trabeculectomy and the Impact on Intraocular Pressure Measurement. J Glaucoma 2017; 26:278-282. [PMID: 27977478 DOI: 10.1097/ijg.0000000000000595] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate corneal biomechanical changes induced by trabeculectomy and their impact on intraocular pressure (IOP) measurements. MATERIALS AND METHODS In total, 35 eyes of 35 consecutive glaucoma patients undergoing first-time trabeculectomy with mitomycin C were enrolled in this prospective interventional case series. Goldmann applanation tonometry (GAT) IOP, central corneal thickness, axial length, and Ocular Response Analyzer measurements [Goldmann-correlated IOP (IOPg), corneal-compensated IOP (IOPcc), corneal hysteresis (CH), and corneal resistance factor (CRF)] were assessed before and 6 months after uncomplicated trabeculectomy. Linear mixed models were used to compare the parameters before and after surgery. RESULTS IOP, central corneal thickness, and axial length showed a strong correlation with CH and CRF preoperatively and postoperatively. After adjusting for these influencing factors, CH changed from 7.75±1.46 to 7.62±1.66 mm Hg (P=0.720) and CRF from 8.67±1.18 to 8.52±1.35 mm Hg (P=0.640) after trabeculectomy, but these changes were not statistically significant. IOP decreased statistically significantly with all IOP measurements (P=0.001). IOPcc was statistically significantly higher than GAT (4.82±5.24 mm Hg; P=0.001) and IOPg (2.92±1.74 mm Hg; P=0.001) preoperatively and postoperatively (GAT, 3.29±3.36 mm Hg; P=0.001; IOPg, 3.35±1.81 mm Hg; P=0.001). The difference between IOPcc and GAT (P=0.5) and IOPcc and IOPg (P=0.06) did not change significantly before or after trabeculectomy. CONCLUSIONS Despite a marked IOP reduction and a possible weakening of the ocular walls after trabeculectomy, corneal structural tissue properties are not altered, and therefore, the accuracy of IOP measurements is not changed postoperatively. It seems likely, however, that Goldmann-correlated IOP measurements are underestimated in glaucoma patients before and after surgery.
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Can Corneal Biomechanical Properties Give Clues About Elasticity of Optic Nerve Scleral Component in Nonarteritic Anterior Ischemic Optic Neuropathy? J Neuroophthalmol 2017; 36:285-9. [PMID: 27389626 DOI: 10.1097/wno.0000000000000406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate corneal biomechanical properties among individuals with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) compared to healthy gender- and age-matched subjects. METHODS The study subjects were separated into 2 groups: 66 eyes of 33 patients with unilateral NAION (study group) and 33 eyes of 33 healthy individuals (control group). Reichert ocular response analyzer (Reichert Ophthalmic Instruments) was used to assess corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure values. Also, central corneal thickness was measured using Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; Costruzioni Strumenti Oftalmici). RESULTS Mean CH and median CRF values were significantly lower in the affected eyes (8.8 ± 1.8 mm Hg, 9.4 mm Hg, respectively) and contralateral unaffected eyes (9.1 ± 1.6 mm Hg, 9.8 mm Hg, respectively) of NAION patients than those in the control group (9.9 ± 1.3 mm Hg, 10.4 mm Hg, respectively; all P < 0.017). Mean IOPcc was significantly higher in the affected eyes of NAION patients (19.2 ± 3.5 mm Hg) than in the eyes of control group (17.1 ± 3.6 mm Hg; P = 0.002). CONCLUSIONS CH and CRF are significantly reduced in patients with NAION, possibly indirectly reflecting structural weakness in the lamina cribrosa.
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Abstract
PURPOSE To determine the intraocular and systemic risk factor differences between a cohort of rapid glaucoma disease progressors and nonrapid disease progressors. DESIGN Retrospective case-control study. METHODS Setting: Five private ophthalmology clinics. STUDY POPULATION Forty-eight rapidly progressing eyes (progression ≥1 dB mean deviation [MD]/year) and 486 non-rapidly progressing eyes (progression <1 dB MD/year). Patients were eligible if they had a diagnosis of glaucoma from their ophthalmologist and if they had greater than or equal to 5 Humphrey visual fields (24-2) conducted. Patients were excluded if their sequential visual fields showed an improvement in MD or if they had greater than 5 dB MD variation in between visits. Patients with obvious neurologic fields were excluded. OBSERVATION PROCEDURE Clinical and demographic data (age, sex, central corneal thickness [CCT], intraocular pressure [IOP], refraction, medications), as well as medical, surgical, and ocular histories, were collected. MAIN OUTCOME MEASURES Risk factor differences between the cohorts were measured using the independent t test, Wald χ2, and binomial regression analysis. RESULTS Rapid progressors were older, had significantly lower CCT and baseline IOPs, and were more likely to have pseudoexfoliation, disc haemorrhages, ocular medication changes, and IOP-lowering surgery. They also had significantly higher rates of cardiovascular disease and hypotension. Subjects with cardiovascular disease were 2.33 times more likely to develop rapidly progressive glaucoma disease despite significantly lower mean and baseline IOPs. CONCLUSION Cardiovascular disease is an important risk factor for rapid glaucoma disease progression irrespective of IOP control.
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Ambrósio, Jr R, Correia FF, Lopes B, Salomão MQ, Luz A, Dawson DG, Elsheikh A, Vinciguerra R, Vinciguerra P, Roberts CJ. Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications. Open Ophthalmol J 2017; 11:176-193. [PMID: 28932334 PMCID: PMC5585467 DOI: 10.2174/1874364101711010176] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/16/2017] [Accepted: 06/15/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.
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Affiliation(s)
- Renato Ambrósio, Jr
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Fernando Faria Correia
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- Ophthalmology Department, Hospital de Braga, Braga, Portugal
| | - Bernardo Lopes
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Marcella Q. Salomão
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- VisareRIO, Rio de Janeiro, Brazil
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Allan Luz
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BRAIN, Rio de Janeiro & Maceió, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Daniel G. Dawson
- The University of Florida Department of Ophthalmology, Gainesville, FL, USA
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool – Liverpool, United Kingdom
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UK
| | - Riccardo Vinciguerra
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, Varese, Italy
| | - Paolo Vinciguerra
- Department of Surgical Sciences, Division of Ophthalmology, University of Insubria, Varese, Italy
- Eye Center, Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano (MI) – Italy
| | - Cynthia J. Roberts
- Department of Ophthalmology & Visual Science, Department of Biomedical Engineering, The Ohio State University – Columbus, OH, USA
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Liu B, McNally S, Kilpatrick JI, Jarvis SP, O'Brien CJ. Aging and ocular tissue stiffness in glaucoma. Surv Ophthalmol 2017; 63:56-74. [PMID: 28666629 DOI: 10.1016/j.survophthal.2017.06.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 06/20/2017] [Accepted: 06/22/2017] [Indexed: 12/27/2022]
Abstract
Glaucoma is a progressive and chronic neurodegenerative disorder characterized by damage to the inner layers of the retina and deformation of the optic nerve head. The degeneration of retinal ganglion cells and their axons results in an irreversible loss of vision and is correlated with increasing age. Extracellular matrix changes related to natural aging generate a stiffer extracellular environment throughout the body. Altered age-associated ocular tissue stiffening plays a major role in a significant number of ophthalmic pathologies. In glaucoma, both the trabecular meshwork and the optic nerve head undergo extensive extracellular matrix remodeling, characterized by fibrotic changes associated with cellular and molecular events (including myofibroblast activation) that drive further tissue fibrosis and stiffening. Here, we review the literature concerning the role of age-related ocular stiffening in the trabecular meshwork, lamina cribrosa, sclera, cornea, retina, and Bruch membrane/choroid and discuss their potential role in glaucoma progression. Because both trabecular meshwork and lamina cribrosa cells are mechanosensitive, we then describe molecular mechanisms underlying tissue stiffening and cell mechanotransduction and how these cellular activities can drive further fibrotic changes within ocular tissues. An improved understanding of the interplay between age-related tissue stiffening and biological responses in the trabecular meshwork and optic nerve head could potentially lead to novel therapeutic strategies for glaucoma treatment.
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Affiliation(s)
- Baiyun Liu
- School of Physics, Conway Institute, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Sara McNally
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Jason I Kilpatrick
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Suzanne P Jarvis
- School of Physics, Conway Institute, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Colm J O'Brien
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland; School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
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Comparison of Corneal Biomechanical Properties between Indian and Chinese Adults. Ophthalmology 2017; 124:1271-1279. [PMID: 28461014 DOI: 10.1016/j.ophtha.2017.03.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/29/2017] [Accepted: 03/29/2017] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To investigate the difference in corneal hysteresis (CH) and corneal resistance factor (CRF) between Indian and Chinese populations. DESIGN Population-based cross-sectional study. PARTICIPANTS Three hundred eighty-two Singaporean Indian persons and 764 Singaporean Chinese 50 years of age or older were included from the Singapore Indian Eye Study and Singapore Chinese Eye Study, respectively. METHODS Participants underwent standardized systemic and ocular examinations and interviewer-administered questionnaires for risk factor assessment. The CH and CRF were measured with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY). Information on genetic ancestry was derived using principal component analysis. Linear regression models were used to investigate the association of CH and CRF with potential risk factors. MAIN OUTCOME MEASURES Corneal hysteresis and CRF. RESULTS After excluding participants with a history of intraocular surgery, a diagnosis of glaucoma suspect or glaucoma, refractive surgery, or presence of corneal abnormalities, CH and CRF readings were available for 382 Indian persons. For each Indian participant, 2 Chinese participants were selected and matched for age and gender (n = 764). There were no differences in the clinical measurements of CH (10.6±1.6 mmHg; P = 0.670) or CRF (10.3±1.7 mmHg; P = 0.103) between the ethnic groups. However, after adjusting for covariates, Indian persons had, on average, 0.18-mmHg higher CH levels than in Chinese (95% confidence interval [CI], 0.02-0.38; P = 0.031). Consistently, CH level was correlated significantly with genetic ancestry in the Southeast Asian population. Corneal resistance factor level was not associated independently with self-reported ethnicity (95% CI, -0.10 to 0.29; P = 0.335). CONCLUSIONS Chinese have lower CH than Indian persons, and this disparity may reflect biomechanical differences of the cornea.
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Abstract
OBJECTIVE To investigate the significance of ultrasound elastography for evaluating the optic nerve in patients with primary open angle glaucoma (POAG). METHODS This prospective, comparative case series included 40 eyes of 40 patients. Twenty eyes with POAG comprised the POAG group, and 20 eyes of 20 patients without glaucoma who admitted to general eye clinic for near vision glasses comprised the control group. All real-time sonographicelastographic examinations were performed by the same physician. The ratio of orbital fat to optic nerve head (ROFON) and lateral rectus to optic nerve head (RLRON) were determined. Statistical analyses were performed using Student t test, Kolmogorov-Smirnov test, and χ test. RESULTS The mean ages of the patients in the study and the control groups were 65.10 ± 7.88 years (range, 48-80 years), and 69.15 ± 7.92 years (range, 55-89 years), respectively (P = 0.113). Mean ROFONs were 1.85 and 6.42 (P < 0.05), and mean RLRONs were 0.65 and 1.07 (P < 0.05) in the control and POAG groups, respectively. CONCLUSIONS Real-time elastography showed increased ROFON and RLRON in POAG patients. This can help to understand optic nerve head biomechanics and clarify glaucoma damage in early glaucoma cases.
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Li BB, Cai Y, Pan YZ, Li M, Qiao RH, Fang Y, Tian T. Corneal Biomechanical Parameters and Asymmetric Visual Field Damage in Patients with Untreated Normal Tension Glaucoma. Chin Med J (Engl) 2017; 130:334-339. [PMID: 28139518 PMCID: PMC5308017 DOI: 10.4103/0366-6999.198920] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background: High intraocular pressure (IOP) and low central corneal thickness (CCT) are important validated risk factors for glaucoma, and some studies also have suggested that eyes with more deformable corneas may be in higher risk of the development and worsening of glaucoma. In the present study, we aimed to evaluate the association between corneal biomechanical parameters and asymmetric visual field (VF) damage using a Corvis-ST device in patients with untreated normal tension glaucoma (NTG). Methods: In this observational, cross-sectional study, 44 newly diagnosed NTG patients were enrolled. Of these, 31 had asymmetric VF damage, which was defined as a 5-point difference between the eyes according to the Advanced Glaucoma Intervention Study scoring system. Corneal biomechanical parameters were obtained using a Corvis-ST device, such as time from start until the first and second applanation is reached (time A1 and time A2, respectively), cord length of the first and second applanation (length A1 and length A2, respectively), corneal speed during the first and second applanation (velocity A1 and velocity A2, respectively), time from start until highest concavity is reached (time HC), maximum amplitude at the apex of highest concavity (def ampl HC), distance between the two peaks at highest concavity (peak dist HC), and central concave curvature at its highest concavity (radius HC). Results: Time A1 (7.19 ± 0.28 vs. 7.37 ± 0.41 ms, P = 0.010), length A1 (1.73 [1.70–1.76] vs. 1.78 [1.76–1.79] mm, P = 0.007), length A2 (1.58 [1.46–1.70] vs. 1.84 [1.76–1.92] mm, P < 0.001), peak dist HC (3.53 [3.08–4.00] vs. 4.33 [3.92–4.74] mm, P = 0.010), and radius HC (6.20 ± 0.69 vs. 6.59 ± 1.18 mm, P = 0.032) were significantly lower in the worse eyes than in the better eyes, whereas velocity A1 and def ampl HC were significantly higher (0.156 [0.149–0.163] vs. 0.145 [0.138–0.152] m/s, P = 0.002 and 1.19 ± 0.13 vs. 1.15 ± 0.13 mm, P = 0.005, respectively). There was no significant difference in time A2, velocity A2, and time HC between the two groups. In addition, no difference was observed in IOP, CCT, and axial length. In the univariate and multivariate analyses, some of the Corvis-ST parameters, including time A1 and def ampl HC, were correlated with known risk factors for glaucoma, and there was also a significant positive correlation between def ampl HC and age. Conclusions: There were differences in dynamic corneal response parameters but not IOP or CCT between the paired eyes of NTG patients with asymmetric VF damage. We suggest that the shape of the cornea is more easily altered in the worse eyes of asymmetric NTG patients.
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Affiliation(s)
- Bai-Bing Li
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
| | - Yu Cai
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
| | - Ying-Zi Pan
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
| | - Mei Li
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
| | - Rong-Hua Qiao
- Department of Ophthalmology, Beijing Tsinghua Changgung Hospital, Beijing 102218, China
| | - Yuan Fang
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
| | - Tian Tian
- Department of Ophthalmology, Peking University First Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100034, China
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Uysal BS, Duru N, Ozen U, Arikan Yorgun M, Akcay E, Caglayan M, Cagil N. Impact of dehydration and fasting on intraocular pressure and corneal biomechanics measured by the Ocular Response Analyzer. Int Ophthalmol 2017; 38:451-457. [DOI: 10.1007/s10792-017-0479-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/19/2017] [Indexed: 10/20/2022]
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Perucho-González L, Sáenz-Francés F, Morales-Fernández L, Martínez-de-la-Casa JM, Méndez-Hernández CD, Santos-Bueso E, Brookes JL, García-Feijoó J. Structural and biomechanical corneal differences between patients suffering from primary congenital glaucoma and healthy volunteers. Acta Ophthalmol 2017; 95:e107-e112. [PMID: 27573413 DOI: 10.1111/aos.13212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/28/2016] [Indexed: 12/18/2022]
Abstract
PURPOSE To determine whether a set of ocular morphometric and biomechanical variables are able to discriminate between healthy volunteers and patients suffering from primary congenital glaucoma (PCG). METHODS Case-control study in which 66 patients with PCG and 94 age-matched healthy subjects were evaluated using ocular response analyser (ORA) to record corneal biomechanical properties. Topographic corneal variables were obtained using the Pentacam in both groups. To determine the ability to discern between both groups, a multivariate binary logistic model was constructed. The outcome was the diagnosis of PCG and the predictors; the corneal variables analysed along with their first-term interactions. Sensitivity and specificity of this model along with the area under the receiver characteristic operating curve (AUC of ROC) were determined. RESULTS The best model to discriminate between both groups included the following predictors: corneal hysteresis (CH), corneal resistance factor (CRF), posterior maximum elevation (PME), anterior maximum elevation (AME) and central corneal thickness (CCT). This model, for a cut-point of 50%, presents a sensitivity of 86.67%, a specificity of 86.89% and an AUC of the ROC curve of 93.16% [95% confidence interval (CI): 88.97-97.35]. The adjusted odds ratios of those predictors which showed a significant discriminating capacity were as follows: for CH, 0.27 (95% confidence interval: 0.15-0.46); for CRF, 2.13 (95% CI: 1.33-3.40); for PME, 1.06 (95% CI: 1.01-1.12); and for AME, 1.35 (95% CI: 1.10-1.66). CONCLUSION Corneal hysteresis (CH), CRF, PME and AME are able to discern between patients with PCG and healthy controls. This fact suggests that there are structural and biomechanical differences between these groups.
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Affiliation(s)
- Lucía Perucho-González
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - Federico Sáenz-Francés
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - Laura Morales-Fernández
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - José María Martínez-de-la-Casa
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - Carmen D. Méndez-Hernández
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - Enrique Santos-Bueso
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
| | - John L. Brookes
- Glaucoma Department; Moorfields Eye Hospital & Great Ormond Street Hospital for Children; London UK
| | - Julián García-Feijoó
- Ophthalmology Department; Clinico San Carlos University Hospital; Sanitary Research Institute of the San Carlos Clinical Hospital; Madrid Spain
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136
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Murphy ML, Pokrovskaya O, Galligan M, O'Brien C. Corneal hysteresis in patients with glaucoma-like optic discs, ocular hypertension and glaucoma. BMC Ophthalmol 2017; 17:1. [PMID: 28068950 PMCID: PMC5223406 DOI: 10.1186/s12886-016-0396-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
Background To compare corneal hysteresis (CH) measurements between patients with glaucoma, ocular hypertension (OHT) and glaucoma-like optic discs (GLD)- defined as a cup to disc ratio greater than or equal to 0.6 with normal intraocular pressure (IOP) and visual fields. The secondary aim was to investigate whether corneal resistance factor (CRF) and central corneal thickness (CCT) differ between patient groups. Methods In this cross sectional study a total of 123 patients (one eye each) were recruited from a glaucoma outpatient department to undergo ocular response analyser (ORA) testing and ultrasound pachymetry as well as clinical examination. A One-way Analysis of Covariance (ANCOVA) was conducted to evaluate the mean difference in CH between the three diagnostic groups (glaucoma, OHT and GLD) correcting for potential confounding factors, IOP and age. Analysis was repeated for CRF and CCT. Results There was a significant difference in mean CH across the three diagnosis groups; F(2, 115) = 96.95; p < 0.001. Mean CH significantly higher for GLD compared to glaucoma (mean difference 1.83, p < 0.001), and significantly higher for OHT compared to glaucoma (mean difference 2.35, p < 0.001). Mean CH was slightly lower in patients with GLD than those with OHT but this difference was not statistically significant. A similar pattern was seen when the analysis was repeated for CRF and CCT. Conclusions Higher CH in GLD and OHT compared to glaucoma suggests increased viscoelasticity of ocular tissues may have a protective role against glaucoma.
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Affiliation(s)
- Melissa L Murphy
- School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, Eccles Street Dublin 7, Dublin, Ireland.
| | - Olya Pokrovskaya
- School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, Eccles Street Dublin 7, Dublin, Ireland
| | - Marie Galligan
- School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, Eccles Street Dublin 7, Dublin, Ireland
| | - Colm O'Brien
- School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, Eccles Street Dublin 7, Dublin, Ireland
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Lee BR, Han KE, Choi KR. The Association between Corneal Biomechanical Properties and Initial Visual Field Defect Pattern in Normal Tension Glaucoma. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2017. [DOI: 10.3341/jkos.2017.58.2.178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Bo Ram Lee
- The Institute of Ophthalmology and Optometry, Department of Ophthalmology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Kyung Eun Han
- The Institute of Ophthalmology and Optometry, Department of Ophthalmology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Kyu Ryong Choi
- The Institute of Ophthalmology and Optometry, Department of Ophthalmology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
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Abstract
PURPOSE OF REVIEW This article summarizes the state-of-the-art in clinical corneal biomechanics, including procedures in which biomechanics play a role, and the clinical consequences in terms of error in estimating intraocular pressure (IOP). RECENT FINDINGS Corneal biomechanical response to refractive surgery can be categorized into either stable alteration of surface shape and thus visual outcome, or unstable biomechanical decompensation. The stable response is characterized by central flattening and peripheral steepening that is potentiated in a stiffer cornea. Two clinical devices for assessing corneal biomechanics do not yet measure classic biomechanical properties, but rather provide assessment of corneal deformation response. Biomechanical parameters are a function of IOP, and both the cornea and sclera become stiffer as IOP increases. Any assessment of biomechanical parameters must include IOP, and one value of stiffness does not adequately characterize a cornea. SUMMARY Corneal biomechanics plays a role in the outcomes of any procedure in which lamellae are transected. Once the corneal structure has been altered in a manner that includes central thinning, IOP measurements with applanation tonometry are likely not valid, and other technologies should be used.
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Applications of Scheimpflug Imaging in Glaucoma Management: Current and Potential Applications. J Ophthalmol 2016; 2016:3062381. [PMID: 28044101 PMCID: PMC5164893 DOI: 10.1155/2016/3062381] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/06/2016] [Accepted: 10/04/2016] [Indexed: 11/24/2022] Open
Abstract
Scheimpflug photography is the basis for a variety of imaging devices that are highly versatile. The applications of Scheimpflug imaging are wide in scope, spanning from evaluation of corneal ectasia to quantifying density in nuclear sclerotic cataracts. The potential uses for Scheimpflug-based devices are expanding and a number of them are relevant in glaucoma. In particular, they can provide three-dimensional image reconstruction of the anterior segment which includes assessment of the iridocorneal angle. Photographic analyses allow also for a noncontact method of estimating central corneal thickness (CCT) and intraocular pressure (IOP), as well as the study of various corneal biomechanical properties, which may be useful for stratifying glaucoma risk.
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Beyazyıldız E, Beyazyıldız O, Arifoğlu HB, Altıntaş AK, Köklü SG. Comparison of ocular response analyzer parameters in primary open angle glaucoma and exfoliative glaucoma patients. Indian J Ophthalmol 2016; 62:782-7. [PMID: 25116770 PMCID: PMC4152647 DOI: 10.4103/0301-4738.138180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
AIM We sought to identify differences in the following measures of the ocular response analyser (ORA) between primary open angle glaucoma (POAG) and exfoliative glaucoma (EXG) patients: Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg). We also sought to relate these ORA measures with central corneal thickness (CCT). MATERIALS AND METHODS This cross-sectional study was conducted on a total of 162 individuals (46 EXG patients, 66 POAG patients and 50 healthy subjects without any ocular and systemic disease). ORA measurements were performed, and a minimum of three readings were obtained from each test subject. Groups were compared according to their ORA parameters. RESULTS The mean CH levels of the EXG, POAG and healthy subjects were 7.6 ± 2.1, 9.1 ± 1.9 and 9.6 ± 1.7 mmHg, respectively. CH was significantly lower in the EXG patients compared to the other groups (P < 0.001).The mean CRF levels of the EXG, POAG and healthy subjects were 9.0 ± 2.0, 10.1 ± 1.7 and 9.8 ± 1.8mmHg, respectively. CRF levels in the eyes of the EXG patients were significantly lower compared to those of either the POAG patients (P = 0.005) or the healthy subjects (P = 0.03), but there was no significant difference in CRF levels between the POAG patients and the healthy subjects (P = 0.59). There was a significant positive correlation between CH and CCT in the EXG patients and healthy subjects (P < 0.001), but this correlation was not present in the POAG patients (P = 0.70). CONCLUSIONS In this study, CH and CRF were found to be significantly reduced in the eyes of EXG patients compared to both the POAG patients and healthy subjects. Reduced CH in EXG patients might result in decreased support of peripapillary scleral structure and increased damage to the optic nerve during IOP increase.
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Central Corneal Thickness and its Associations With Ocular and Systemic Factors in an Urban West African Population. Am J Ophthalmol 2016; 169:268-275. [PMID: 27423792 DOI: 10.1016/j.ajo.2016.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 11/21/2022]
Abstract
PURPOSE To assess the associations of central corneal thickness (CCT) with ocular and systemic factors in a West African population. DESIGN Population-based cross-sectional study. METHODS Participants aged ≥40 years in the Tema Eye Survey who had clinically normal corneas were included in this study. CCT was determined bilaterally using handheld ultrasound pachymetry. The association between CCT and ocular or systemic factors was analyzed with univariable linear regression. Multivariable linear regression analysis was performed for variables significantly associated with CCT in the univariable analysis. Main outcome measures were CCT (μm) and its associations with age, sex, IOP, cup-to-disc ratio (CDR), glaucoma, hypertension, and diabetes. RESULTS A total of 6806 eligible subjects were identified, of whom 5603 (82.3%) participated in the Tema Eye Survey. A total of 4737 participants (84.5% of participants) of West African descent and clinically normal corneas were included. The mean age ± standard deviation (SD) of participants was 51.2 ± 9.7 years and 38.7% were male. The mean ± SD CCT in the population was 533.9 ± 34.0 μm. In the multivariable linear regression analysis, increased CCT was significantly associated with younger age, male sex, and higher IOP (all P < .001). There were no significant associations between CCT and CDR, glaucoma, hypertension, and diabetes. CONCLUSIONS This population-based cross-sectional survey of West African adults found a significant association between increased CCT and younger age, male sex, and higher IOP but not glaucoma or CDR. Variations in corneal thickness may influence the accuracy of IOP measurements in African persons.
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Hong Y, Shoji N, Morita T, Hirasawa K, Matsumura K, Kasahara M, Shimizu K. Comparison of corneal biomechanical properties in normal tension glaucoma patients with different visual field progression speed. Int J Ophthalmol 2016; 9:973-8. [PMID: 27500103 DOI: 10.18240/ijo.2016.07.06] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 11/21/2015] [Indexed: 11/23/2022] Open
Abstract
AIM To compare the corneal biomechanical properties difference by ocular response analyzer (ORA) in normal tension glaucoma (NTG) patients with different visual field (VF) progression speed. METHODS NTG patients with well-controlled Goldmann applanation tonometer (GAT) who routinely consulted Kitasato University Hospital Glaucoma Department between January 2010 and February 2014 were enrolled. GAT and ORA parameters including corneal compensated intraocular pressure (IOPcc), Goldmann estimated intraocular pressure (IOPg), corneal hysteresis (CH), corneal resistance factor (CRF) were recorded. VF was tested by Swedish interactive threshold algorithm (SITA)-standard 30-2 fields. All patients underwent VF measurement regularly and GAT did not exceed 15 mm Hg at any time during the 3y follow up. Patients were divided into four groups according to VF change over 3y, and ORA findings were compared between the upper 25(th) percentile group (slow progression group) and the lower 25(th) percentile group (rapid progression group). RESULTS Eighty-two eyes of 56 patients were studied. There were 21 eyes (21 patients) each in rapid and slow progression groups respectively. GAT, IOPcc, IOPg, CH, CRF were 12.1±1.4 mm Hg, 15.8±1.8 mm Hg, 12.8±2.0 mm Hg, 8.4±1.1 mm Hg, 7.9±1.3 mm Hg respectively in rapid progression group and 11.5±1.3 mm Hg, 13.5±2.1 mm Hg, 11.2±1.6 mm Hg, 9.3±1.1 mm Hg, 8.2±0.9 mm Hg respectively in slow progression group (P=0.214, <0.001, 0.007, 0.017, 0.413, respectively). In bivariate correlation analysis, IOPcc, IOPcc-GAT and CH were significant correlated with mΔMD (r=-0.292, -0.312, 0.228 respectively, P=0.008, 0.004, 0.039 respectively). CONCLUSION Relatively rapid VF progression occurred in NTG patients whose IOPcc are rather high, CH are rather low and the difference between IOPcc and GAT are relatively large. Higher IOPcc and lower CH are associated with VF progression in NTG patients. This study suggests that GAT measures might underestimate the IOP in such patients.
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Affiliation(s)
- Ying Hong
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100191, China
| | - Nobuyuki Shoji
- Department of Rehabilitation, Orthoptics and Visual Science Course, Kitasato University School of Allied Health Sciences, Sagamihara City 252-0373, Japan; Department of Ophthalmology, Kitasato University Hospital, Sagamihara City 252-0373, Japan
| | | | - Kazunori Hirasawa
- Department of Rehabilitation, Orthoptics and Visual Science Course, Kitasato University School of Allied Health Sciences, Sagamihara City 252-0373, Japan
| | | | - Masayuki Kasahara
- Department of Ophthalmology, Kitasato University Hospital, Sagamihara City 252-0373, Japan
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In Vivo Corneal Biomechanical Properties with Corneal Visualization Scheimpflug Technology in Chinese Population. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7840284. [PMID: 27493965 PMCID: PMC4963556 DOI: 10.1155/2016/7840284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/28/2016] [Accepted: 06/19/2016] [Indexed: 12/18/2022]
Abstract
Purpose. To determine the repeatability of recalculated corneal visualization Scheimpflug technology (CorVis ST) parameters and to study the variation of biomechanical properties and their association with demographic and ocular characteristics. Methods. A total of 783 healthy subjects were included in this study. Comprehensive ophthalmological examinations were conducted. The repeatability of the recalculated biomechanical parameters with 90 subjects was assessed by the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Univariate and multivariate linear regression models were used to identify demographic and ocular factors. Results. The repeatability of the central corneal thickness (CCT), deformation amplitude (DA), and first/second applanation time (A1/A2-time) exhibited excellent repeatability (CV% ≤ 3.312% and ICC ≥ 0.929 for all measurements). The velocity in/out (Vin/out), highest concavity- (HC-) radius, peak distance (PD), and DA showed a normal distribution. Univariate linear regression showed a statistically significant correlation between Vin, Vout, DA, PD, and HC-radius and IOP, CCT, and corneal volume, respectively. Multivariate analysis showed that IOP and CCT were negatively correlated with Vin, DA, and PD, while there was a positive correlation between Vout and HC-radius. Conclusion. The ICCs of the recalculated parameters, CCT, DA, A1-time, and A2-time, exhibited excellent repeatability. IOP, CCT, and corneal volume significantly influenced the biomechanical properties of the eye.
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Lanzagorta-Aresti A, Perez-Lopez M, Palacios-Pozo E, Davo-Cabrera J. Relationship between corneal hysteresis and lamina cribrosa displacement after medical reduction of intraocular pressure. Br J Ophthalmol 2016; 101:290-294. [PMID: 27474156 PMCID: PMC5339555 DOI: 10.1136/bjophthalmol-2015-307428] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 01/19/2016] [Accepted: 05/28/2016] [Indexed: 11/30/2022]
Abstract
Purpose To evaluate the relationship between the displacement of the lamina cribrosa (LC) and prelaminar tissue with corneal hysteresis (CH) using spectral-domain coherence tomography (SD-OCT) after reducing intraocular pressure (IOP) with medical treatment. Methods Sixty-one eyes of 61 patients with ocular hypertension or primary open-angle glaucoma who were going to start with treatment were imaged by means of 12 cross-sectional scans of the optic nerve using enhanced depth imaging SD-OCT before and after 1 week of treatment. We used the ‘follow-up’ mode to make sure that all the measurements were performed in the same location. We also measured the CH using an Ocular Response Analyzer, and we related it to the magnitude of displacement of LC and prelaminar tissue and the thickness of both structures. Results There was a significant variation of LC thickness from 132.66±37.40 to 160.09±41.13 µm (p<0001). LC distance was significantly reduced from 258.53±145 µm before treatment to 239.86±135 µm after it. No significant changes were found in the thickness and movement of prelaminar tissue before and after treatment. The only factors related with LC displacement were CH (R2=0.48) and age (R2=0.42). Conclusions A significant increase in LC thickness and a reduction in the posterior displacement of LC but not in the prelaminar tissue were demonstrated after IOP reduction with medical treatment. The factors most related with LC displacement were age and CH.
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Affiliation(s)
| | - Marta Perez-Lopez
- Orbit and Oculoplastics Unit, FISABIO Oftalmologia Medica, Valencia, Spain
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Evaluation of biomechanical properties of the cornea in patients with primary hyperparathyroidism. Int Ophthalmol 2016; 37:519-524. [PMID: 27423457 DOI: 10.1007/s10792-016-0292-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
Abstract
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. The differences in ORA parameters and CCT between study and control group participants were analyzed. The mean CH in study and control groups was 8.7 ± 1.9 mmHg (5.3-13.7 mmHg) and 9.8 ± 1.5 mmHg (7.7-14.3 mmHg), respectively (p = 0.018). The mean CRF was 9.5 ± 1.8 (5.5-13.7) in the study group compared with 9.8 ± 1.5 (6.2-12.8) in the control group. The difference for CRF was not statistically significant (p = 0.41). In study and control group, corneal-compensated IOP (IOPcc) values were 18.2 ± 4.2 and 16.9 ± 2.7 mmHg, respectively (p = 0.12). Mean IOP measurement values with GAT were 16.3 ± 3.4 mmHg for study group and 16.5 ± 2.7 mmHg for control group (p = 0.71). The mean differences of IOPcc and IOPGAT in the study group eyes were higher than that of control group eyes (1.9 vs. 0.4 mmHg). CCT was 536.5 ± 25.4 µm (490-593 µm) in study group eyes compared with 534.2 ± 31.4 µm (472-602 µm) in control eyes (p = 0.75). Hyperparathyroidism could be associated with a decrease of CH. The differences between IOPcc and IOPGAT in these patients were higher than normal subjects. Underestimation of IOP readings with GAT may be a consequence of the lower CH in patients with hyperparathyroididsm.
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Zhang C, Tatham AJ, Abe RY, Diniz-Filho A, Zangwill LM, Weinreb RN, Medeiros FA. Corneal Hysteresis and Progressive Retinal Nerve Fiber Layer Loss in Glaucoma. Am J Ophthalmol 2016; 166:29-36. [PMID: 26949135 DOI: 10.1016/j.ajo.2016.02.034] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 11/19/2022]
Abstract
PURPOSE To investigate the relationship between corneal hysteresis (CH) and progressive retinal nerve fiber layer (RNFL) loss in a cohort of patients with glaucoma followed prospectively over time. DESIGN Prospective observational cohort study. METHODS One hundred and eighty-six eyes of 133 patients with glaucoma were followed for an average of 3.8 ± 0.8 years, with a median of 9 visits during follow-up. The CH measurements were acquired using the Ocular Response Analyzer (Reichert Instruments, Depew, New York, USA) and RNFL measurements were obtained at each follow up visit using spectral-domain optical coherence tomography (SDOCT). Random-coefficient models were used to investigate the relationship between baseline CH, central corneal thickness (CCT), average intraocular pressure (IOP), and rates of RNFL loss during follow-up, while adjusting for potentially confounding factors. RESULTS Average baseline RNFL thickness was 76.4 ± 18.1 μm and average baseline CH was 9.2 ± 1.8 mm Hg. CH had a significant effect on rates of RNFL progression. In the univariable model, including only CH as a predictive factor along with time and their interaction, each 1 mm Hg lower CH was associated with a 0.13 μm/year faster rate of RNFL decline (P = .011). A similar relationship between low CH and faster rates of RNFL loss was found using a multivariable model accounting for age, race, average IOP, and CCT (P = .015). CONCLUSIONS Lower CH was significantly associated with faster rates of RNFL loss over time. The prospective longitudinal design of this study provides further evidence that CH is an important factor to be considered in the assessment of the risk of progression in patients with glaucoma.
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Affiliation(s)
- Chunwei Zhang
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Andrew J Tatham
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Ricardo Y Abe
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Alberto Diniz-Filho
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Linda M Zangwill
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Robert N Weinreb
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California
| | - Felipe A Medeiros
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California.
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Yaoeda K, Fukushima A, Shirakashi M, Fukuchi T. Comparison of intraocular pressure adjusted by central corneal thickness or corneal biomechanical properties as measured in glaucomatous eyes using noncontact tonometers and the Goldmann applanation tonometer. Clin Ophthalmol 2016; 10:829-34. [PMID: 27274187 PMCID: PMC4869658 DOI: 10.2147/opth.s106836] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose To investigate the correlation coefficients between intraocular pressure (IOP) before and after adjusting for central corneal thickness (CCT) and corneal biomechanical properties. Patients and methods A total of 218 eyes of 218 patients with primary open-angle glaucoma (mean age =71.5 years; mean spherical equivalent =−0.51 D; mean deviation determined by Humphrey visual field analyzer =−3.22 dB) were included in this study. The tIOP and tIOPCCT, which were adjusted by the CCT (with tIOP meaning IOP not adjusted by CCT, as determined using the CT-1P; and tIOPCCT meaning IOP adjusted by CCT, as determined using the CT-1P), were determined using a noncontact tonometer. The IOPg and IOPCCT, which were adjusted by CCT, and IOPcc adjusted by corneal biomechanical properties were determined using a Reichert 7CR (with IOPg meaning IOP not adjusted by CCT or corneal biomechanical properties, as determined using the Reichert 7CR; IOPCCT meaning IOP adjusted by CCT, as determined using the Reichert 7CR; and IOPcc meaning IOP adjusted by corneal biomechanical properties, as determined using the Reichert 7CR). The GT and GTCCT adjusted by CCT were determined using a Goldmann applanation tonometer (with GT meaning IOP not adjusted by CCT, as determined using the Goldmann applanation tonometer; and with GTCCT meaning IOP adjusted by CCT, as determined using the GAT). Pearson’s correlation coefficients among the IOPs were calculated and compared. P-values <0.05 were considered as statistically significant. Results The tIOP, tIOPCCT, IOPg, IOPCCT, IOPcc, GT, and GTCCT were 14.8±2.5, 15.0±2.4, 13.1±3.2, 13.3±3.1, 13.7±2.9, 13.2±2.4, and 13.4±2.3 mmHg (mean ± standard deviation), respectively. The correlation coefficient between tIOPCCT and tIOP (r=0.979) was significantly higher than that between tIOPCCT and the other IOPs (r=0.668–0.852; P<0.001, respectively). The correlation coefficient between IOPCCT and IOPg (r=0.994) or IOPcc and IOPg (r=0.892) was significantly higher than that between IOPCCT or IOPcc and the other IOPs (r=0.669–0.740; P<0.001, respectively). The correlation coefficient between GTCCT and GT (r=0.989) was significantly higher than that between GTCCT and the other IOPs (r=0.669–0.740; P<0.001, respectively). Conclusion The IOP adjusted by CCT or corneal biomechanical properties depends on the measurement instrument itself, rather than the adjustment methods, for eyes of patients with primary open-angle glaucoma.
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Affiliation(s)
- Kiyoshi Yaoeda
- Yaoeda Eye Clinic, Niigata University Graduate School of Medical and Dental Sciences, Nagaoka, Japan; Division of Ophthalmology and Visual Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Atsushi Fukushima
- Yaoeda Eye Clinic, Niigata University Graduate School of Medical and Dental Sciences, Nagaoka, Japan
| | | | - Takeo Fukuchi
- Division of Ophthalmology and Visual Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Meda R, Wang Q, Paoloni D, Harasymowycz P, Brunette I. The impact of chronic use of prostaglandin analogues on the biomechanical properties of the cornea in patients with primary open-angle glaucoma. Br J Ophthalmol 2016; 101:120-125. [PMID: 27162226 PMCID: PMC5293847 DOI: 10.1136/bjophthalmol-2016-308432] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/01/2016] [Accepted: 04/13/2016] [Indexed: 11/23/2022]
Abstract
Aims To determine the influence of prostaglandin analogues (PGAs) on corneal biomechanical properties in patients undergoing chronic treatment for primary open-angle glaucoma (POAG). Methods Prospective, interventional case–control study. 70 eyes from 35 patients with POAG on chronic PGA therapy were recruited. One eye per patient underwent PGA cessation for 6 weeks while the contralateral eye continued to receive the treatment. Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOP) (IOPcc), central corneal thickness (CCT) and Goldmann tonometry (Haag-Streit AG, Koeniz, Switzerland) IOP (IOPGAT) were measured at baseline (visit 1), 6 weeks after PGA cessation (visit 2) and 6 weeks after PGAs reinitiation (visit 3) and were analysed using a linear mixed-effect model. The discrepancy between IOPcc and IOPGAT was defined as IOP bias (IOPcc—IOPGAT). Results Baseline characteristics were comparable between the two groups. In the study eyes, significant increases (p<0.0001) were detected at visit 2 in CH (9.0±1.8 vs 10.3±1.7 mm Hg), CRF (10.5±2.1 vs 11.7±2.1 mm Hg), CCT (541.8±43.2 vs 551.9±41.9 μm) and IOPGAT (15.4±3.0 vs 18.4±3.8 mm Hg). IOP bias in this group was significantly lowered at visit 2 (p<0.0001). These effects were reversed at visit 3. The control eyes did not demonstrate any significant changes over the study period. Conclusion Topical PGAs induce reversible reduction in CH, CRF and CCT in patients with POAG. These changes contribute to underestimation of the IOP measured by Goldmann applanation tonometry and warrant caution when assessing response to treatment. Trial registration number NCT02388360, Results.
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Affiliation(s)
- Roman Meda
- Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada.,Montreal Glaucoma Institute, Montreal, Quebec, Canada
| | - Qianqian Wang
- Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
| | - David Paoloni
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Paul Harasymowycz
- Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada.,Montreal Glaucoma Institute, Montreal, Quebec, Canada.,Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Isabelle Brunette
- Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada.,Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
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Lanza M, Iaccarino S, Bifani M. In vivo human corneal deformation analysis with a Scheimpflug camera, a critical review. JOURNAL OF BIOPHOTONICS 2016; 9:464-477. [PMID: 26871552 DOI: 10.1002/jbio.201500233] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 06/05/2023]
Abstract
Corneal morphological analysis has greatly improved in recent years, providing physicians with new and reliable parameters to study. Moreover, today corneal functional too is a routine analysis, thanks to biomechanical evaluation allowed by an ocular response analyzer (Reichert Ophthalmic Instrument, Depew, NY, USA). Corvis ST (OCULUS Optikgeräte GmbH, Wetzlar, Germany), that relies on the ultrahigh speed Scheimpflug camera, is a new device providing corneal deformation parameters measured ny scanning the cornea response to an air puff; it is an instrument able to measure intraocular pressure too. This device could open up a whole new prospective in screening, detecting and managing corneal diseases, intraocular pressure measurement and in evaluating surgical procedures involving the cornea. This paper provides a comprehensive explanation of Corvis ST measurement principles and parameters and a literature review of scientific studies.
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Affiliation(s)
- Michele Lanza
- Dipartimento Multidisciplinare di Scienze Mediche, Chirurgiche e Odontoiatriche, Seconda Università di Napoli, Napoli, Italy.
- Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy.
| | - Stefania Iaccarino
- Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy
| | - Mario Bifani
- Dipartimento Multidisciplinare di Scienze Mediche, Chirurgiche e Odontoiatriche, Seconda Università di Napoli, Napoli, Italy
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