Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles

Wan, Kin; Cheung, Sin Wan; Wolffsohn, James S.; Orr, Janis B.; Cho, Pauline

doi:10.1136/bmjophth-2018-000204

Cited by 20 publications

(21 citation statements)

References 48 publications

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“…The biomechanical behavior of the cornea is affected by several factors such as age, IOP, CCT, corneal hydration status, corneal tissue composition, and several other factors, some of which are still under investigation (McMonnies, 2012 ; Roberts, 2014 ). The results of this study demonstrate a positive correlation between CCT, mean keratometry, and IOPnct with both CH and CRF, while AXL showed a negative correction only with CH, in keeping with previous studies (Wong and Lam, 2015 ; Qiu et al, 2016 ; Wan et al, 2018 ).…”

Section: Discussionsupporting

confidence: 92%

“…Whilst a previous study suggested that CH as corneal biomechanical parameter can predict myopia progression in children (Wan et al, 2018); the results of the current study suggest that although there are no significant differences in CH in different myopia groups, there is a positive correlation between CH with SE overall. However, the present patient cohort only included adults and the results cannot be extrapolated to children.…”

Section: Discussioncontrasting

confidence: 84%

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Corneal Biomechanical Properties in Varying Severities of Myopia

Sedaghat

Momeni‐Moghaddam

Abbas

et al. 2021

Front. Bioeng. Biotechnol.

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Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length.Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT.Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia.Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.

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Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 84%

Corneal Biomechanical Properties in Varying Severities of Myopia

Sedaghat

Momeni‐Moghaddam

Abbas

et al. 2021

Front. Bioeng. Biotechnol.

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“…This study proves that the initial corneal thickness has no correlation with the axial elongation, which is consistent with the conclusions of the current literature [12,27]. Lee et al concluded that the initial corneal thickness was negatively correlated with the axial elongation, but they proposed that this correlation is highly dependent on the age, and believed that the younger wearers had thinner and more exible corneal thickness which is less likely to be affected by the cornea shape changes caused by the orthokeratology lens [11].…”

Section: Discussionsupporting

confidence: 93%

Multi-Factor Analysis of the Influence of Orthokeratology on Controlling Myopia in Adolescents

Wen¹,

Ma²,

Xiao³

et al. 2020

Preprint

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Background To investigate which baseline factors are predictive for axial length growth over an average period of 1 years in a group of adolescents wearing orthokeratology (OK) contact lenses.Methods In this retrospective study, the clinical records of 189 new OK wearers (378 eyes) between 2014 and 2018 at Xiangya Hospital of Central South University were reviewed. The primary outcome measure was axial length change from baseline to the time of 1 year. Independent variables included baseline measures of age at initiation of OK wear, refractive error (spherical equivalent), corneal thickness, corneal curvature. (1) Age group, 8 ~ 10 years old is the first group, 10 ~ 13 years old is the second group, ≥13 years old is the third group; (2) Myopia degree group, ≥-3.00D is the first group, -3.00 ~ -6.00D is the second group, <-6.00D is the third group; (3) corneal thickness group, ≤550μm is the first group,> 550μm is the second group; (4) corneal curvature group, ≤42.0D is The first group, 42.0 ~ 44.0D is the second group,> 44.0D is the third group.Results ANOVA was used to analyze the difference between the baseline axial length of each group and the axial length for 1 year after continuous wearing of orthokeratology: (1)The mean axial difference between different age groups are 0.251mm, 0.033mm,and 0.112mm, and the difference of the three groups is not statistically significant (F=2.279，P=0.104). By pairwise comparison, only the difference between the first group and the third group is statistically significant (P=0.041); (2) The mean axial difference between different myopia degree groups are 0.173mm, 0.109mm and -0.008mm, and the difference of the three groups is statistically significant (F=8.340，P=0.000 ). By pairwise comparison, the difference between the first group and the second group is statistically significant (P=0.000) and the difference between the first group and the third group is statistically significant(P=0.016); (3) The mean axial difference between different corneal thickness groups and corneal curvature groups is not statistically significant.Conclusions OKs are effective in controlling axial length elongation and myopic progression in adolescents, particularly in younger children with higher myopia.

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“…While the geometric properties of the cornea change following ortho-k, the magnitude of change does not correlate with metrics of corneal biomechanics. A recent study [125] reported a significant difference in corneal hysteresis in spectacle-wearing children showing slow and fast axial elongation and hence, it may be beneficial to recommend ortho-k as early as possible for myopic children with low corneal hysteresis.…”

Section: Corneal Biomechanicsmentioning

confidence: 99%

BCLA CLEAR - Orthokeratology

Vincent

Cho

Chan³

et al. 2021

Contact Lens and Anterior Eye

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102

103

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Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children.This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size.

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Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles

Cited by 20 publications

References 48 publications

Corneal Biomechanical Properties in Varying Severities of Myopia

Corneal Biomechanical Properties in Varying Severities of Myopia

Multi-Factor Analysis of the Influence of Orthokeratology on Controlling Myopia in Adolescents

BCLA CLEAR - Orthokeratology

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