Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

Purpose To characterize corneal biomechanical properties utilizing a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (CorVis ST, CST) in keratoconic corneas following continuous high intensity, high irradiance corneal cross-linking. Design Prospective longitudinal single-centre study at a tertiary referral center. Methods Corneal biomechanical properties were measured in patients with progressive keratoconus undergoing high intensity (30 mW/cm2), high irradiance (5.4 J/cm2), accelerated corneal cross-linking with continuous exposure to ultraviolet-A for 4 min. CST was used to assess corneal biomechanical properties pre-operatively and at 1, 3, 6 and 12 months post-operatively. CST output videos were further analyzed using several previously reported algorithms. Results A total of 25 eyes of 25 participants were examined. The mean age of participants was 20.9 ± 5.3 years; 56% were male and 80% were of Māori or Pacific Island origin. Energy absorbed area (mN mm), was the only significantly changed parameter compared to baseline at all time points measuring 3.61 ± 1.19 preoperatively, 2.81 ± 1.15 at 1 month ( p = 0.037), 2.79 ± 0.81 ( p = 0.033) at 3 months, 2.76 ± 0.95 ( p = 0.028) at 6 months and 2.71 ± 1.18 ( p = 0.016) at 12 months. Conclusions The significant difference between the pre and post-operative energy absorbed area appears to reflect changes in corneal viscous properties that occur following corneal cross-linking.

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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

Arquivos Brasileiros de Oftalmologia ◽

10.1590/s0004-27492013000500005 ◽

2013 ◽

Vol 76 (5) ◽

pp. 278-281 ◽

Cited By ~ 14

Author(s):

Fernando Faria Correia ◽

Isaac Ramos ◽

Cynthia J. Roberts ◽

Andreas Steinmueller ◽

Matthias Krug ◽

...

Keyword(s):

Material Properties ◽

High Speed ◽

Chamber Pressure ◽

Deformation Response ◽

Ultra High Speed ◽

Scheimpflug Imaging

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Applications of Scheimpflug Imaging in Glaucoma Management: Current and Potential Applications

Journal of Ophthalmology ◽

10.1155/2016/3062381 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Alexander T. Nguyen ◽

Tiffany Liu ◽

Ji Liu

Keyword(s):

Intraocular Pressure ◽

Image Reconstruction ◽

Central Corneal Thickness ◽

Corneal Thickness ◽

Anterior Segment ◽

Three Dimensional ◽

Biomechanical Properties ◽

Scheimpflug Imaging ◽

Potential Applications ◽

Corneal Biomechanical Properties

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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