The Biomechanical Response of the Cornea in Orthokeratology

Wu, Jinfang; Fang, Wenxuan; Xu, Huiwen; Liu, Xiaode; Zhao, Deqiang; Rong, Qiguo

doi:10.3389/fbioe.2021.743745

Cited by 16 publications

(18 citation statements)

References 52 publications

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“…Hence, the included participants with higher baseline SER had relatively higher Kf values. 28 However, the results of correlation analysis did not show a significant correlation between baseline Kf and choroidal thickness changes, indicating that initial Kf may not be a prominent factor that affects choroidal thickness changes in this study.…”

Section: Discussioncontrasting

confidence: 64%

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

Wang,

Chen,

Kang

et al. 2023

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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Objective: To investigate the changes in choroidal thickness and axial length after orthokeratology in adolescents with low-to-moderate myopia and to explore the relationship between choroidal thickness and axial length variation. Methods: Thirty eyes with low-to-moderate myopia were retrospectively studied, and optometric data were collected before and after 6 months of continuous orthokeratology. Axial length and choroidal and foveal thicknesses were measured using optical biometry and enhanced depth imaging–spectral domain optical coherence tomography, respectively. Results: Axial length in the low myopia group increased (P<0.001) after 6 months of orthokeratology, and the variation was greater than that in the moderate myopia group (P<0.05). The subfoveal choroidal thickness in low and moderate myopia groups increased (P<0.01), and the variation was greater in the moderate myopia group (P<0.05). Choroidal thickness in all seven measured spots increased, with the variation of subfovea, nasal 1 mm to fovea, and temporal 1 mm to fovea being statistically significant (P<0.001, P<0.05, and P<0.05). The change in axial length was negatively associated with subfoveal and average choroidal thicknesses (P<0.01). Conclusion: Adolescents with moderate myopia presented better axial length control after 6 months of orthokeratology. The choroidal thickness of low and moderate myopic eyes increased, and the variation was more significant in moderate myopic eyes. The axial length control effects can be associated with an increase in the subfoveal and average choroidal thickness.

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Section: Discussioncontrasting

confidence: 64%

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

Wang,

Chen,

Kang

et al. 2023

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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“…Corneal biomechanics is one of the factors that potentially affects corneal response to orthokeratology ( González-Méijome et al, 2008 ; Wu et al, 2021 ). The viscoelasticity of the cornea was not only associated with the response but also the recovery of orthokeratology ( González-Méijome et al, 2008 ).…”

Section: Introductionmentioning

confidence: 99%

Assessment of corneal biomechanics in anisometropia using Scheimpflug technology

Gao

Ren

et al. 2022

Front. Bioeng. Biotechnol.

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Purpose: To investigate the relationship between corneal biomechanical and ocular biometric parameters, and to explore biomechanical asymmetry between anisometropic eyes using the corneal visualization Scheimpflug technology device (Corvis ST).Methods: 180 anisometropic participants were included. Participants were divided into low (1.00≤△Spherical equivalent (SE) < 2.00D), moderate (2.00D≤△SE < 3.00D) and high (△SE ≥ 3.00D) anisometropic groups. Axial length (AL), keratometry, anterior chamber depth (ACD) and corneal biomechanical parameters were assessed using the OA-2000 biometer, Pentacam HR and Corvis ST, respectively.Results: The mean age of participants was 16.09 ± 5.64 years. Stress-Strain Index (SSI) was positively correlated with SE (r = 0.501, p < 0.001) and negatively correlated with AL (r = -0.436, p < 0.001). Some other Corvis ST parameters had weak correlation with SE or AL. Corneal biomechanical parameters except for time of first applanation (A1T), length of second applanation (A2L), deformation amplitude (DA), first applanation stiffness parameter (SPA1) and ambrosia relational thickness-horizontal (ARTh) were correlated with ametropic parameters (SE or AL) in multiple regression analyses. A1T, velocity of first applanation (A1V), time of second applanation (A2T), A2L, velocity of second applanation (A2V), corneal curvature radius at highest concavity (HCR), peak distance (PD), DA, deformation amplitude ratio max (2 mm) (DAR), SPA1, integrated radius (IR), and SSI showed significant differences between fellow eyes (p < 0.05). There was no significant difference in asymmetry of corneal biomechanics among the three groups (p > 0.05). Asymmetry of some biomechanical parameters had weak correlation with asymmetry of mean corneal curvatures and ACD. However, asymmetry of corneal biomechanical parameters was not correlated with asymmetry of SE or AL (p > 0.05).Conclusion: More myopic eyes had weaker biomechanical properties than the contralateral eye in anisometropia. However, a certain linear relationship between anisometropia and biomechanical asymmetry was not found.

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“…23 Thickness has little effect on the biomechanics of the cornea under the OK lens. 17,19 Therefore, we established the corneal model as a three-layer structure: the outermost layer, stroma, and the innermost layer, with a 500 μm constant thickness profile. The epithelium and Bowman's membrane are regarded as one layer called the outermost layer with a thickness of 40 μm.…”

Section: Corneal Geometrymentioning

confidence: 99%

Biomechanical study of cornea response under orthokeratology lens therapy: A finite element analysis

Zhao

Zhai

Xiang

et al. 2023

Numer Methods Biomed Eng

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Orthokeratology (OK) is becoming a mainstream modality for myopia correction and control, but its underlying mechanism is not yet fully understood. In this study, the biomechanical response of cornea under the OK lens was investigated to further understand the mechanism of OK therapy. Numerical models of the cornea and OK lens with different corneal refractive powers and myopia degrees were established to analyze features and differences of the spatial displacement and stress distribution in different areas of the anterior corneal surface by finite element method. Displacement distributions on the anterior cornea surface with refractive powers of 39.5, 43, 46 D, and myopia degrees of −1.0, −3.0, −6.0 D demonstrate similar deformation trends and nearly rotationally symmetrical attributes of different corneal parameters. Displacement of mid‐peripheral cornea was significantly high compared with that of the central and peripheral cornea, peaking at ~2.4 mm off the corneal apex. The stress increased with the increase in myopia degrees and was significantly large for the myopia degrees of −6.0 D at S1; the stress at S2 and S6 was low and stable and did not differ much at S3; the stress at S4 and S5, however, was extremely high. In summary, simulation result of orthokeratology can effectively evaluate the performance of OK lens and it properly associates with the differential map of the corneal topography. The base curve of the OK lens may also play a role in mid‐peripheral corneal steepening. The design around the OK lens' alignment curve needs to be optimized.

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The Biomechanical Response of the Cornea in Orthokeratology

Cited by 16 publications

References 52 publications

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

Assessment of corneal biomechanics in anisometropia using Scheimpflug technology

Biomechanical study of cornea response under orthokeratology lens therapy: A finite element analysis

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