Acoustic Micro-Tapping Optical Coherence Elastography to Quantify Corneal Collagen Cross-Linking

Kirby, Mitchell A.; Pelivanov, Ivan; Regnault, Gabriel; Pitre, John J.; Wallace, Ryan T; O’Donnell, Matthew; Wang, Ke; Shen, Tueng T.

doi:10.1016/j.xops.2022.100257

Cited by 5 publications

(1 citation statement)

References 76 publications

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“…Recently, OCE was able to reveal an altered strain distribution in ex vivo rat eyes after CXL treatment (Kling, 2020) that was restricted to the regions exposed to UV irradiation. When applied to ex vivo human corneas, OCE measured the changes in the anisotropic elastic properties induced by CXL (Kirby et al, 2023). OCE has also been used in vivo: De Stefano and others (De Stefano et al, 2020) demonstrated for the first time on human eyes the effectiveness of OCE in detecting the depth-dependent biomechanical abnormalities in keratoconus by applanation of the cornea with a lens.…”

Section: Introductionmentioning

confidence: 99%

Optomechanical assessment of photorefractive corneal cross-linking via optical coherence elastography

Frigelli,

Büchler,

Kling

2023

Front. Bioeng. Biotechnol.

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Purpose: Corneal cross-linking (CXL) has recently been used with promising results to positively affect corneal refractive power in the treatment of hyperopia and mild myopia. However, understanding and predicting the optomechanical changes induced by this procedure are challenging.Methods: We applied ambient pressure modulation based optical coherence elastography (OCE) to quantify the refractive and mechanical effects of patterned CXL and their relationship to energy delivered during the treatment on porcine corneas. Three different patterned treatments were performed, designed according to Zernike polynomial functions (circle, astigmatism, coma). In addition, three different irradiation protocols were analyzed: standard Dresden CXL (fluence of 5.4 J/cm2), accelerated CXL (fluence of 5.4 J/cm2), and high-fluence CXL (fluence of 16.2 J/cm2). The axial strain distribution in the stroma induced by ocular inflation (Δp = 30 mmHg) was quantified, maps of the anterior sagittal curvature were constructed and cylindrical refraction was assessed.Results: Thirty minutes after CXL, there was a statistically significant increase in axial strain amplitude (p < 0.050) and a reduction in sagittal curvature (p < 0.050) in the regions treated with all irradiation patterns compared to the non-irradiated ones. Thirty-6 hours later, the non-irradiated regions showed compressive strains, while the axial strain in the CXL-treated regions was close to zero, and the reduction in sagittal curvature observed 30 minutes after the treatment was maintained. The Dresden CXL and accelerated CXL produced comparable amounts of stiffening and refractive changes (p = 0.856), while high-fluence CXL produced the strongest response in terms of axial strain (6.9‰ ± 1.9‰) and refractive correction (3.4 ± 0.9 D). Tripling the energy administered during CXL resulted in a 2.4-fold increase in the resulting refractive correction.Conclusion: OCE showed that refractive changes and alterations in corneal biomechanics are directly related. A patient-specific selection of both, the administered UV fluence and the irradiation pattern during CXL is promising to allow customized photorefractive corrections in the future.

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Section: Introductionmentioning

confidence: 99%

Optomechanical assessment of photorefractive corneal cross-linking via optical coherence elastography

Frigelli,

Büchler,

Kling

2023

Front. Bioeng. Biotechnol.

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Nonlinear fourth-order elastic characterization of the cornea using torsional wave elastography

Callejas,

Faris,

Torres

et al. 2023

Phys Eng Sci Med

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Measuring the mechanical nonlinear properties of the cornea remains challenging due to the lack of consensus in the methodology and in the models that effectively predict its behaviour. This study proposed developing a procedure to reconstruct nonlinear fourth-order elastic properties of the cornea based on a mathematical model derived from the theory of Hamilton et al. and using the torsional wave elastography (TWE) technique. In order to validate its diagnostic capability of simulated pathological conditions, two different groups were studied, non-treated cornea samples (n=7), and ammonium hydroxide ($$NH_4OH$$ N H 4 O H ) treated samples (n=7). All the samples were measured in-plane by a torsional wave device by increasing IOP from 5 to 25 mmHg with 5 mmHg steps. The results show a nonlinear variation of the shear wave speed with the IOP, with higher values for higher IOPs. Moreover, the shear wave speed values of the control group were higher than those of the treated group. The study also revealed significant differences between the control and treated groups for the Lamé parameter $$\mu$$ μ (25.9–6.52 kPa), third-order elastic constant A (215.09–44.85 kPa), and fourth-order elastic constant D (523.5–129.63 kPa), with p-values of 0.010, 0.024, and 0.032, respectively. These findings demonstrate that the proposed procedure can distinguish between healthy and damaged corneas, making it a promising technique for detecting diseases associated with IOP alteration, such as corneal burns, glaucoma, or ocular hypertension.

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A review of the epithelial and stromal effects of corneal collagen crosslinking

Bradford,

Luo,

Brown

et al. 2023

The Ocular Surface

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Acoustic Micro-Tapping Optical Coherence Elastography to Quantify Corneal Collagen Cross-Linking

Cited by 5 publications

References 76 publications

Optomechanical assessment of photorefractive corneal cross-linking via optical coherence elastography

Optomechanical assessment of photorefractive corneal cross-linking via optical coherence elastography

Nonlinear fourth-order elastic characterization of the cornea using torsional wave elastography

A review of the epithelial and stromal effects of corneal collagen crosslinking

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