Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

Ambrósio, Renato; Ramos, Isaac; Luz, Allan; Faria, Fernando Correa; Steinmueller, Andreas; Krug, Matthias; Belin, Michael W.; Roberts, Cynthia J.

doi:10.1590/s0034-72802013000200005

Cited by 165 publications

(134 citation statements)

References 19 publications

(19 reference statements)

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“…[13][14][15] The Corvis ST (Oculus Optikgeräte GmbH; Wetzlar, Germany) was later introduced as a noncontact tonometer, which monitors the response of the cornea to an air pressure pulse using an ultra-highspeed Scheimpflug camera, and uses the captured image sequence to produce estimates of IOP and deformation response parameters. 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.…”

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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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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“…The deformation data obtained by the Corvis ST provide information related to the biomechanical properties of the tissue, but further investigation is necessary to quantify elasticity and viscoelas ticity. As mentioned in previous studies, the chamber pressure level has a strong influence on the deformation response (18) . This new technology also helps in understanding of the variation of DA in corneamo dels due to other parameters, such as thickness and structural composition.…”

Section: Discussionmentioning

confidence: 65%

“…This device is a new generation imaging system that provides in vivo biomechanical information, avoiding the limitations of prior in vivo and in vitro techniques (13,18) . Three distinct contact lenses with known structures and material compositions were tested under different chamber pressure conditions.…”

Section: Discussionmentioning

confidence: 99%

“…The Corvis ST is an NCT with an UHS Scheimpflug camera, taking 4,330 frames per second. The 8 mm horizontal UHS Scheimpflug camera records 140 frames, which documents, in detail, the deformation movement of the cornea during NCT measurement (18) . The deformation amplitude (DA) during NCT was determined as the highest displacement of the apex at the highest concavity (HC) moment.…”

Section: Methodsmentioning

confidence: 99%

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Impact of chamber pressure and material properties on the deformation response of corneal models measured by dynamic ultra-high-speed Scheimpflug imaging

Faria-Correia¹,

Ramos²,

Roberts³

et al. 2013

Arq. Bras. Oftalmol.

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“…7,8 Despite its potential, the former has demonstrated limited ability for screening of ectatic disease. 9,10 The latter features advanced parameters that can help detect early ectasia and fruste keratoconus with higher accuracy.…”

Section: Introductionmentioning

confidence: 99%

First Clinical Impressions on the Integrated Corneal Tomography and Corneal Deformation with Scheimpflug Imaging

Haddad¹,

Barnwell²,

Rocha³

et al. 2017

International Journal of Keratoconus and Ectatic Corneal Diseases

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The purpose of this study is to report the preliminary findings and the retrospective clinical impressions of the integrated corneal tomography and corneal deformation parameters with a dynamic ultra-high-speed Scheimpflug camera equipped with a noncontact tonometer. Twelve eyes of six patients were evaluated by the Scheimpflug imaging system of the Pentacam HR and Corvis ST (OCULUS Optikgeräte GmbH, Wetzlar, Germany) devices. The parameters used were the Belin/Ambrósio deviation (BAD-D) and Corvis biomechanical index (CBI), as well as the recently published tomographic and biomechanical index (TBI), combined with a detailed clinical data and evaluation of normal eyes and patients with different stages of corneal ectasia.

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Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

Cited by 165 publications

References 19 publications

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

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

Impact of chamber pressure and material properties on the deformation response of corneal models measured by dynamic ultra-high-speed Scheimpflug imaging

First Clinical Impressions on the Integrated Corneal Tomography and Corneal Deformation with Scheimpflug Imaging

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