Corneal biomechanical characteristics measured by the CorVis Scheimpflug technology in eyes with primary open‐angle glaucoma and normal eyes

Tian, Lei; Wang, Dajiang; Wu, Ying; Meng, Xiaoli; Chen, Bing; Ge, Mei; Huang, Yifei

doi:10.1111/aos.12672

Cited by 72 publications

(71 citation statements)

References 24 publications

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“…Previous studies have considered DA as an exclusively corneal phenomenon [10][11][12] ; however, this study provides evidence of the distribution and significant difference between DA (provided by the device) and the isolated corneal (MCD) and orbital (MOD) components in a population of healthy corneas. Isolation of the orbital component should be used when analyzing deformation characteristics in diseases that only affect the cornea.…”

Section: Discussionmentioning

confidence: 68%

“…This is in agreement with Leung et al, 11 who demonstrated a statistically significant, weak relationship (r ¼ 0.002) between age and DA in a group of normal, glaucoma, and glaucoma-suspect eyes. Tian et al 12 also described a significant positive correlation (r ¼ 0.43) between age and DA. Conversely, others have discovered no significant correlations between age and DA.…”

Section: Discussionmentioning

confidence: 87%

“…Previously, studies have described DA as a solely corneal reaction. [10][11][12] However, the in vivo response to an air-pulse is not purely corneal. 13 It includes an indirect and collateral globe displacement secondary to the transfer of energy to the orbital tissue and extraocular muscles.…”

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confidence: 99%

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Quantitative Analysis of Corneal Energy Dissipation and Corneal and Orbital Deformation in Response to an Air-Pulse in Healthy Eyes

Vellara

Ali

Gokul

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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Citation: Vellara HR, Ali NQ, Gokul A, Turuwhenua J, Patel DV, McGhee CNJ. Quantitative analysis of corneal energy dissipation and corneal and orbital deformation in response to an airpulse in healthy eyes. Invest Ophthalmol Vis Sci. 2015;56:6941-6947. DOI:10.1167/iovs.15-17396 PURPOSE. To examine and evaluate ocular biomechanical metrics and additionally derived corneal and orbital components using a noncontact Scheimpflug-based tonometer (CorVis ST) in a population of healthy eyes. METHODS.A total of 152 eyes of 152 participants were examined by slit-lamp biomicroscopy, corneal tomography, and the CorVis ST (CST). This determined the distribution of outputs from the CST, such as deformation amplitude (DA), and additionally derived parameters, including maximum corneal deformation (MCD), maximum orbital deformation (MOD), and corneal energy dissipation (CED).RESULTS. The mean age of participants was 35.88 6 13.8 years. Deformation amplitude significantly correlated with age (r ¼ 0.24, P ¼ 0.002) but not sex or ethnicity (P > 0.05). Multiple linear regression analysis revealed significant correlations between DA and age (r ¼ 0.19, P ¼ 0.006) and DA and IOP (r ¼ À0.59, P < 0.001). Age correlated with MCD (r ¼ 0.20, P ¼ 0.01), MOD (r ¼ 0.18, P ¼ 0.03), and CED (r ¼ 0.39, P < 0.001). Males had a lower MOD than females (0.24 vs. 0.26 mm, respectively, P ¼ 0.01); however, there were no differences in MCD or CED between sexes (P > 0.05). There were no significant differences between ethnicities for MCD, MOD, and CED (P > 0.05). Multiple linear regression analysis revealed significant correlations between MCD and IOP (r ¼ À0.65, P < 0.001), CED and age (r ¼ 0.41, P < 0.001), CED and IOP (r ¼ 0.28, P ¼ 0.001), and between CED and central corneal thickness (CCT) (r ¼ À0.36, P < 0.001).CONCLUSIONS. The isolation of the corneal component (MCD) should be used when analyzing deformation characteristics in diseases that only affect the cornea. This study establishes a baseline for a population of healthy eyes. Future publications will identify differences in MCD, MOD, and CED between healthy and diseased populations.

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 87%

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Quantitative Analysis of Corneal Energy Dissipation and Corneal and Orbital Deformation in Response to an Air-Pulse in Healthy Eyes

Vellara

Ali

Gokul

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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“…16 Several articles have recently been published on the possible applications of the Corvis ST, particularly evaluating possible biomechanical differences in the cornea after undergoing refractive surgery procedures, [17][18][19][20][21][22] between normal and keratoconic patients, [23][24][25][26] after cross-linking, 27 and in patients with glaucoma. [28][29][30][31] However, it has been demonstrated that IOP and pachymetry have important influences on most corneal biomechanical metrics provided by both the Corvis ST and ORA. [32][33][34] It is therefore relevant to investigate the distribution and normal limits for the in vivo corneal biomechanical data derived from dynamic corneal response parameters, and determine whether these metrics have correlations with IOP and corneal thickness.…”

Section: Resultsmentioning

confidence: 99%

Influence of Pachymetry and Intraocular Pressure on Dynamic Corneal Response Parameters in Healthy Patients

et al. 2016

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n 1619, Scheiner provided the first precise description of the corneal shape using glass balls of known curvatures.1 From that first description, many other diagnostic tools have been developed to describe corneal shape, from keratometry to corneal topography (front surface curvature maps), 2 then into three-dimensional corneal tomography systems.3 More recently, it has been shown that corneal biomechanical behavior plays an important role in maintaining corneal shape, which is necessary for light refraction and clear vision, 4 and should therefore be considered in understanding the development of ectatic diseases 5,6 and the results of surgery. 4,7 Until recently, the evaluation of corneal biomechanical properties had been restricted to ex vivo laboratory studies 5,8 and mathematical corneal models. METHODS: Seven hundred five healthy patients were included in this multicenter retrospective study. The biomechanical response data were analyzed to obtain normative values with their dependence on corrected and clinically validated intraocular pressure estimates developed using the finite element method (bIOP), central corneal thickness (CCT), and age, and to evaluate the influence of bIOP, CCT, and age. RESULTS:The results showed that all DCRs were correlated with bIOP except deflection amplitude (DefA) ratio, highest concavity (HC) radius, and inverse concave radius. The analysis of the relationship of DCRs with CCT indicated that HC radius, inverse concave radius, deformation amplitude (DA) ratio, and DefA ratio were correlated with CCT (rho values of 0.343, -0.407, -0.444, and -0.406, respectively). The age group subanalysis revealed that primarily whole eye movement followed by DA ratio and inverse concave radius were the parameters that were most influenced by age. Finally, custom software was created to compare normative values to imported examinations.CONCLUSIONS: HC radius, inverse concave radius, DA ratio, and DefA ratio were shown to be suitable parameters to evaluate in vivo corneal biomechanics due to their independence from IOP and their correlation with pachymetry and age. The creation of normative values allows the interpretation of an abnormal examination without the need to match every case with another normal patient matched for CCT and IOP.[J Refract Surg. 2016;32(8):550-561.]

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“…[5][6][7]10,[14][15][16][17][18][19][20]29,32,33 Other studies have found that other baseline factors such as axial length, 21,23 age, 27 and CCT 23 also are significantly associated with corneal biomechanical parameters. To accurately understand the relationship between corneal biomechanics and ocular diseases, the effect of baseline factors on corneal deformation parameters must be clarified.…”

Section: Discussionmentioning

confidence: 99%

Factors Associated With Corneal Deformation Responses Measured With a Dynamic Scheimpflug Analyzer

Miki

Maeda

Ikuno

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. The purpose of this study was to clarify correlations between corneal deformation parameters measured with a dynamic Scheimpflug analyzer and baseline factors such as axial length, intraocular pressure (IOP), age, central corneal thickness (CCT), and corneal curvature.METHODS. Ninety-six eyes of 96 healthy subjects (mean 55.2 6 16.1 years of age) were examined using a dynamic Scheimpflug analyzer. Eighteen of 35 deformation parameters were selected for analyses based on measurement reliability and clinical relevance. The associations between corneal deformation parameters and axial length, IOP, age, CCT, and average corneal power were evaluated using multivariate regression analyses.RESULTS. Deformation parameters were correlated significantly with axial length (n ¼ 13), IOP (n ¼ 13), age (n ¼ 8), and CCT (n ¼ 6) in the multivariate models. Longer axial length corresponded with greater corneal deformability, less viscous damping, and less movement of the entire eye. Higher IOP was associated with greater corneal resistance and less movement of the entire eye. Older age was associated with less corneal deformability and greater movement of the entire eye. Corneal curvature was correlated significantly with only three deformation parameters.CONCLUSIONS. This study clarified the substantial impact of axial length, age, and IOP on the biomechanical responses of the cornea and the entire eye. In contrast, corneal curvature did not affect most of the deformation parameters. The current results confirmed the importance of corneal biomechanics, especially in eyes with longer axial length and in older subjects.

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Corneal biomechanical characteristics measured by the CorVis Scheimpflug technology in eyes with primary open‐angle glaucoma and normal eyes

Cited by 72 publications

References 24 publications

Quantitative Analysis of Corneal Energy Dissipation and Corneal and Orbital Deformation in Response to an Air-Pulse in Healthy Eyes

Quantitative Analysis of Corneal Energy Dissipation and Corneal and Orbital Deformation in Response to an Air-Pulse in Healthy Eyes

Influence of Pachymetry and Intraocular Pressure on Dynamic Corneal Response Parameters in Healthy Patients

Factors Associated With Corneal Deformation Responses Measured With a Dynamic Scheimpflug Analyzer

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