In Vivo Biomechanical Changes Associated With Keratoconus Progression

Padmanabhan, Prema; Lopes, Bernardo; Eliasy, Ashkan; Abass, Ahmed; Elsheikh, Ahmed

doi:10.1080/02713683.2022.2058020

Cited by 8 publications

(4 citation statements)

References 31 publications

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“…6 In addition, Padmanabhan et al showed a simultaneous deterioration of the SSI and IIR among the disease progression by À0.10 ± 0.06 and +0.95 ± 1.04 mm, respectively. 32 By contrast, the SSI increased by +0.08 in our CXL group showing enhanced biomechanical stiffness, whereas the uFE group did not change in the same period. Furthermore, the mean change of both SSI and IIR differed between the CXL and the uFE group, which underpinned the alterations in stiffness of the CXL group.…”

Section: Discussioncontrasting

confidence: 54%

Repeatability of corneal deformation response parameters by dynamic ultra–high-speed Scheimpflug imaging before and after corneal crosslinking

Herber

Vinciguerra

Tredici

et al. 2023

J Cataract Refract Surg

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Section: Discussioncontrasting

confidence: 54%

Repeatability of corneal deformation response parameters by dynamic ultra–high-speed Scheimpflug imaging before and after corneal crosslinking

Herber

Vinciguerra

Tredici

et al. 2023

J Cataract Refract Surg

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“…Liu et al reported that the SSI was relatively stable before 35 years of age and was positively correlated with anterior corneal curvature and IOP and negatively correlated with axial length (AL) in a healthy Chinese population ( Liu et al, 2020 ). Thus, SSI could be suitable for the assessment of reduction in corneal stiffness in the natural progression of keratoconus and help recognize potential keratoconic eyes ( Padmanabhan et al, 2022 ; Liu et al, 2021a ). Some studies reported correlations between SSI values and IOP; therefore, SSI values may also be used for the differentiation of glaucoma types ( Ye et al, 2021 ; Silva et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

Effect of myopia and astigmatism deepening on the corneal biomechanical parameter stress-strain index in individuals of Chinese ethnicity

Liu

Pang

Ming

et al. 2022

Front. Bioeng. Biotechnol.

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Purpose: To investigate the differences in corneal biomechanical parameter stress–strain index (SSI) among different degrees of myopic eyes in Chinese individuals and to analyze the relevant factors of the SSI.Methods: This study analyzed the right eyes of 240 participants (240 eyes) aged 18–34 years. The participants were divided into low-, moderate-, high-, and ultra-high myopia groups according to their spherical equivalent (SE), with 60 eyes included in each group. Spherical, cylinder, and SE were measured via automatically integrated optometry. Intraocular pressure (IOP) was measured using a non-contact tonometer. AL was measured using an IOLMaster device. Corneal curvature and central corneal thickness (CCT) were measured using a Pentacam. SSI and biomechanical corrected IOP (bIOP) were measured via corneal visualization Scheimpflug technology (Corvis ST). The statistical analyses included one-sample Kolmogorov–Smirnov tests and normal distribution histogram methods, Levene variance homogeneity tests, Pearson’s correlation analyses, multiple linear stepwise regression analyses, one-way ANOVA, and LSD t-tests.Results: The mean (±SD) age of the 240 participants was (24.97 ± 4.16) years. The SSI was positively correlated with spherical, cylinder, SE, CCT, IOP, and bIOP and negatively correlated with K1 and AL (r = 0.475, 0.371, 0.497, 0.169, 0.291, 0.144, −0.154, and −0.464, respectively; all p < 0.05), but were not correlated with age, K2, or Km (all p > 0.05). Multiple linear regression analysis performed with SSI as the dependent variable, and spherical, cylinder, K1, CCT, and IOP as independent variables produced the following regression equation: SSI = 0.989 + 0.017 spherical + 0.042 cylinder +0.018 IOP (R2 = 0.402, F = 31.518, p < 0.001). The SSI values in the low-, moderate-, high-, and ultra-high myopia groups were 0.945 ± 0.135, 0.940 ± 0.128, 0.874 ± 0.110, and 0.771 ± 0.104, respectively. The values decreased sequentially, and the differences between pairs were statistically significant (all p < 0.05), except for that between the low- and moderate-myopia groups (p > 0.05).Conclusion: SSI decreased with increasing myopia and astigmatism in the Chinese participants. The SSI was significantly lower in high and ultra-high myopia, especially ultra-high myopia. These findings indicate that increased corneal elasticity may be related to the pathogenesis of high and ultra-high myopia.

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“…A previous study revealed that the SSI was not significantly different between eyes with mild keratoconus and normal eyes, and the AUROC was 0.642 for detecting keratoconus ( Herber et al, 2022 ), which is similar to that in our study ( Supplementary Tables S1, S2 ), suggesting that the SSI alone was not suitable for screening keratoconus. However, the SSI was proven to decrease significantly during the reduction of corneal stiffness in the progression of keratoconus ( Padmanabhan et al, 2022 ) and increased after corneal cross-linking ( Nishida et al, 2022 ), demonstrating that the SSI may be more suitable for monitoring the progression and treatment efficacy in keratoconus, however, its application in screening keratoconus still needs to be further explored.…”

Section: Discussionmentioning

confidence: 99%

Comparison of bilateral differential characteristics of corneal biomechanics between keratoconus and normal eyes

Xian,

Zhao,

Sun

et al. 2023

Front. Bioeng. Biotechnol.

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Purpose: To compare bilateral differences in corneal biomechanics between keratoconus and normal eyes.Methods: In this case-control study, 346 eyes of 173 patients (aged 22.1 ± 6.1 years) with keratoconus (KC group) and 378 eyes of 189 patients (aged 26.7 ± 5.6 years) with ametropia (control group) were enrolled. Corneal tomography and biomechanical properties were examined using Pentacam HR and Corvis ST, respectively. The corneal biomechanical parameters were compared between eyes with forme fruste keratoconus (FFKC) and normal eyes. Bilateral differences in corneal biomechanical parameters were compared between the KC and control groups. Receiver operating characteristic (ROC) analysis was used to assess discriminative efficacies.Results: The areas under the ROC curves (AUROCs) of stiffness parameter at the first applanation (SP-A1) and Tomographic and Biomechanical Index (TBI) for identifying FFKC were 0.641 and 0.694, respectively. The bilateral differential values of major corneal biomechanical parameters were significantly increased in the KC group (all p < 0.05), except for the Corvis Biomechanical Index (CBI). The AUROCs of the bilateral differential values of the deformation amplitude ratio at 2 mm (ΔDAR2), Integrated Radius (ΔIR), SP-A1 (ΔSP-A1), and the maximum inverse concave radius (ΔMax ICR) for discriminating keratoconus were 0.889, 0.884, 0.826, and 0.805, respectively. The Logistic Regression Model-1 (comprising of ΔDAR2, ΔIR, and age) and the Logistic Regression Model-2 (comprising of ΔIR, ΔARTh, ΔBAD-D, and age) had AUROCs of 0.922 and 0.998, respectively, for discriminating keratoconus.Conclusion: The bilateral asymmetry of corneal biomechanics was significantly increased in keratoconus compared with normal eyes, which may be helpful for the early detection of keratoconus.

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In Vivo Biomechanical Changes Associated With Keratoconus Progression

Cited by 8 publications

References 31 publications

Repeatability of corneal deformation response parameters by dynamic ultra–high-speed Scheimpflug imaging before and after corneal crosslinking

Repeatability of corneal deformation response parameters by dynamic ultra–high-speed Scheimpflug imaging before and after corneal crosslinking

Effect of myopia and astigmatism deepening on the corneal biomechanical parameter stress-strain index in individuals of Chinese ethnicity

Comparison of bilateral differential characteristics of corneal biomechanics between keratoconus and normal eyes

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