Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

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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Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

10.21203/rs.3.rs-18474/v2 ◽

2020 ◽

Author(s):

A-Yong Yu ◽

Hui Shao ◽

Anpeng Pan ◽

Qinmei Wang ◽

Zixu Huang ◽

...

Keyword(s):

Axial Length ◽

High Myopia ◽

Anterior Segment ◽

Biomechanical Properties ◽

Corvis St ◽

Negatively Associated ◽

Scheimpflug Imaging ◽

Biomechanical Parameters ◽

Corneal Biomechanical Properties ◽

Myopia Control

Abstract Background: To investigate the biomechanical properties of the cornea in myopic eyes using corneal visualization scheimpflug technology (Corvis ST). The relationships between the biomechanical properties of the cornea and the degree of myopia were also investigated.Methods: 265 eyes of 265 subjects were included. Based on spherical equivalent (SE) in diopters (D), participants were divided into four groups: low myopia/control (SE: -0.50 to -3.00D), moderate myopia (SE: -3.00 to -6.00D), high myopia (SE: -6.00 to -10.00D) and severe myopia (SE greater than -10.00D). Axial length (AL), anterior segment parameters, and corneal biomechanical properties were obtained with the Lenstar LS900, Pentacam HR and Corvis ST, respectively.Results: Mean (±SD) SE was -7.29±4.31D (range: -0.63 to -25.75D). Mean AL was 26.31±1.82mm (range: 21.87 to 31.94mm). Significant differences were detected within the four groups in terms of six corneal biomechanical parameters: deformation amplitude (DA), time from start until second applanation (A2-time), length of flattened cornea at the second applanation (A2-length), corneal velocity during the first and second applanation (A2-velocity), time from start to highest concavity (HC-time), and central curvature at highest concavity (HC radius). AL was positively associated with DA whereas negatively associated with A1-velocity and A2-length. SE was positively associated with A2-time, HC-time and A2-velocity, whereas negatively associated with DA. IOP was positively associated with four corneal biomechanical parameters and negatively associated with three parameters.Conclusions: Eyes with severe myopia showed greater DA, lesser A2 time, HC time, and faster A2-velocity compared to low to high myopia. This suggests the cornea becomes weaker and more deformable with elongation of axial length with corresponding increases in myopia. DA, A2-time and A2-velocity could be useful corneal biomechanical indicators in patients with myopia.

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Corneal Biomechanical Properties in High Myopia Measured by Dynamic Scheimpflug Imaging Technology

Optometry and Vision Science ◽

10.1097/opx.0000000000001152 ◽

2017 ◽

Vol 94 (12) ◽

pp. 1074-1080 ◽

Cited By ~ 11

Author(s):

Miao He ◽

Wei Wang ◽

Hui Ding ◽

Xingwu Zhong

Keyword(s):

High Myopia ◽

Biomechanical Properties ◽

Imaging Technology ◽

Scheimpflug Imaging ◽

Corneal Biomechanical Properties

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Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

10.21203/rs.3.rs-18474/v1 ◽

2020 ◽

Author(s):

A-Yong Yu ◽

Hui Shao ◽

Anpeng Pan ◽

Qinmei Wang ◽

Zixu Huang ◽

...

Keyword(s):

Anterior Segment ◽

Biomechanical Properties ◽

Control Group ◽

Spherical Equivalent ◽

Corvis St ◽

Scheimpflug Imaging ◽

Biomechanical Parameters ◽

Anterior Segment Parameters ◽

Corneal Biomechanical Properties ◽

Myopia Control

Abstract Background To investigate the biomechanical properties of the cornea in myopic eyes using corneal visualization scheimpflug technology (Corvis ST). The relationships between the biomechanical properties of the cornea and the degree of myopia were also investigated.Methods 265 eyes of 265 subjects were included. According to spherical equivalent (SE) in diopters (D), participants were divided into four groups: low myopia/control group (SE: -0.50 to -3.00D), moderate myopia group (SE: -3.00 to -6.00D), high myopia group (SE: -6.00 to -10.00D) and severe myopia group (SE greater than -10.00D). Axial length (AL), anterior segment parameters, and corneal biomechanical properties were obtained with the Lenstar LS900, Pentacam HR and Corvis ST, respectively. Results Mean (±SD) SE was -7.29±4.31D (range: -0.63 to -25.75D). Mean AL was 26.31±1.82mm (range: 21.87 to 31.94mm). Significant differences were detected within the four groups in terms of six corneal biomechanical parameters: deformation amplitude (DA), time from start until second applanation (A2-time), length of flattened cornea at the second applanation (A2-length), corneal velocity during the first and second applanation (A2-velocity), time from start to highest concavity (HC-time), and central curvature at highest concavity (HC radius). DA was positively correlated with AL ( r =0.16, P =0.009) and negatively correlated with SE ( r =-0.20, P =0.001). A2-time, A2-velocity, A2-length and HC-time were positively correlated with SE and negatively correlated with AL.Conclusions The alterations in corneal biomechanics may be associated with the degree of myopia. DA and A2-velocity may be useful corneal biomechanical indicators in patients with myopia.

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Influence of corneal biomechanical properties on IOP indices in patients with keratoconus

The Eye ◽

10.33791/2222-4408-2019-4-15-19 ◽

2019 ◽

Vol 21 (128) ◽

pp. 15-19

Author(s):

Irina Bubnova ◽

Veronica Averich ◽

Elena Belousova

Keyword(s):

Disease Progression ◽

Corneal Thickness ◽

Central Zone ◽

Biomechanical Properties ◽

Resistance Factor ◽

Corneal Resistance Factor ◽

Mean Values ◽

Coefficient Of Elasticity ◽

D Values ◽

Corneal Biomechanical Properties

Purpose: Evaluation of corneal biomechanical prop¬erties and their influence on IOP indices in patients with keratoconus. Material and methods. The study included 194 eyes with keratoconus (113 patients aged from 23 to 36 years old). Corneal refraction in central zone varied from 48.25 to 56.75 D, values of corneal thickness ranged from 279 to 558 μm. Patients were divided into 4 groups according to Amsler classification: I stage – 40 eyes; II stage – 78 eyes; III stage – 54 eyes and IV stage – 22 eyes. Standard ophthal¬mological examination was carried out including pneumo¬tonometry. IOP indices and values of biomechanical prop¬erties were evaluated by dynamic bidirectional pneumatic applanation and pneumatic impression. Results. Study of corneal biomechanical properties in patients with keratoconus showed a decrease of such biomechanical indices as corneal hysteresis (CH) on aver¬age to 8.42±1.12 mm Hg, corneal resistance factor (CRF) – to 7.45±0.96 mm Hg, coefficient of elasticity (CE) – 5.35± 0.87 mm Hg. Values of these indices strongly depended on the stage of keratoconus. In the whole sample, the aver¬age corneal compensated IOP (IOPcc) amounted to 15.08± 2.43 mm Hg, Goldman IOP (IOPg) was 11.61±2.37 mm Hg and pneumatic tonometry IOP (IOPp) was 10.13±2.94 mm Hg. IOPcc indices didn’t have any statistically significant differ¬ence in dependence on the stage of keratoconus (р>0.473), while in process of disease progression IOPg and IOPp indi¬ces showed statistically significant decrease of mean values. Conclusion. Progression of keratoconus led to a de¬crease in corneal biomechanical properties which deter¬mine reduction of such indices as IOPg and IOPp in contrast to IOPcc.

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