In vivo characterization of corneal biomechanics

Piñero, David P.; Alcón, Natividad

doi:10.1016/j.jcrs.2014.03.021

Cited by 110 publications

(99 citation statements)

References 110 publications

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“…13,41 A material with simple elastic properties could be described with a single number, the elastic modulus, defined by the slope of the stress-strain curve. In an elastic material, the loading and unloading phase follow the same path.…”

Section: Discussionmentioning

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: Discussionmentioning

confidence: 99%

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

et al. 2016

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“…3 The particular arrangement, density, and position of corneal fibers lead to its elastic behavior. 4 When subject to compression or stretching, the cornea reorganizes its layers, increasing in elasticity in order to reach a new equilibrium. 5,6 Corneal stability relies on different factors, such as intraocular pressure (IOP) or the action of extraocular muscles, 7 but it can also be affected by other elements, such as refractive surgery.…”

Section: Introductionmentioning

confidence: 99%

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

Poyales

Garzón

Mendicute

et al. 2017

Eye

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“…1 For this reason, significant research in corneal biomechanics has been done during the past few years, with important efforts made to develop a device for noninvasive in vivo measurement of the biomechanical properties of the human cornea. The use of an air puff as a load to apply on the cornea and analysis of the deformation induced by this type of load is the basis of the 2 currently available devices for characterizing the corneal biomechanical properties in clinical practice.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the ability to identify some cases in which a biomechanical alteration is present, there is a significant limitation in the sensitivity of measurements that detect corneal biomechanical alterations. 1 The main factors in this are the use of nonstandardized and not well understood parameters for characterizing the corneal biomechanics and the potential coupling of corneal thickness and IOP with these parameters. The dynamic bidirectional applanation device measures the CH parameter, which is the difference between 2 pressure values recorded during a bidirectional air-puff applanation.…”

Section: Discussionmentioning

confidence: 99%

“…11 The dynamic Scheimpflug analyzer device is a noncontact tonometer that enables monitoring the corneal reaction to an air impulse by means of a highspeed Scheimpflug camera (4330 frames/sec). 1 The device measures biomechanical parameters such as deformation amplitude or first applanation time. 1 These parameters have been shown to be correlated with IOP and pachymetry.…”

Section: Discussionmentioning

confidence: 99%

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Interaction between diurnal variations of intraocular pressure, pachymetry, and corneal response to an air puff: Preliminary evidence

Ariza-Gracia

Piñero

Rodrı́guez

et al. 2015

Journal of Cataract and Refractive Surgery Online Case Reports

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Diurnal changes in corneal geometry, pachymetry, and intraocular pressure (IOP) in a healthy eye were recorded. The deformation response to an air puff was simulated using 3 levels of corneal stiffness. The response was dependent on IOP and pachymetry and not only on the biomechanical properties of the cornea. Similarly, the maximum variability due to the diurnal changes in pachy- metry and IOP in the corneal displacement generated by the air puff was found to reach 5%. There- fore, diurnal changes in IOP and corneal thickness were able to induce some variability in the air puff–based corneal deformation response. This potential variability should be considered when the biomechanical properties of the cornea are analyzed with air-puff devices

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In vivo characterization of corneal biomechanics

Abstract: Neither author has a financial or proprietary interest in any material or method mentioned.

Cited by 110 publications

References 110 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

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

Interaction between diurnal variations of intraocular pressure, pachymetry, and corneal response to an air puff: Preliminary evidence

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