Optical coherence elastography assessment of corneal viscoelasticity with a modified Rayleigh-Lamb wave model. (February 2017)

• Record Type: Journal Article
• Authors: Han, Zhaolong; Li, Jiasong; Singh, Manmohan; Wu, Chen; Liu, Chih-hao; Raghunathan, Raksha; Aglyamov, Salavat R.; Vantipalli, Srilatha; Twa, Michael D.; Larin, Kirill V.
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 66(2017)
• Page Start: 87
• Page End: 94
• Publication Date: 2017-02
• Subjects: Modified Rayleigh-Lamb frequency equation -- Optical coherence elastography -- Viscoelasticity -- Cornea -- Crosslinking -- Intraocular pressure; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2016.11.004
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: The biomechanical properties of the cornea play a critical role in forming vision. Diseases such as keratoconus can structurally degenerate the cornea causing a pathological loss in visual acuity. UV-A/riboflavin corneal collagen crosslinking (CXL) is a clinically available treatment to stiffen the cornea and restore its healthy shape and function. However, current CXL techniques do not account for pre-existing biomechanical properties of the cornea nor the effects of the CXL treatment itself. In addition to the inherent corneal structure, the intraocular pressure (IOP) can also dramatically affect the measured biomechanical properties of the cornea. In this work, we present the details and development of a modified Rayleigh-Lamb frequency equation model for quantifying corneal biomechanical properties. After comparison with finite element modeling, the model was utilized to quantify the viscoelasticity of in situ porcine corneas in the whole eye-globe configuration before and after CXL based on noncontact optical coherence elastography measurements. Moreover, the viscoelasticity of the untreated and CXL-treated eyes was quantified at various IOPs. The results showed that the stiffness of the cornea increased after CXL and that corneal stiffness is close to linear as a function of IOP. These results show that the modified Rayleigh-Lamb wave model can provide an accurate assessment of corneal viscoelasticity, which could be used for customized CXL therapies. Graphical abstract: Highlights: Detailed development of a modified Rayleigh-Lamb frequency equation (mRLFE) model. The mRLFE and OCE can be used to assess corneal viscoelasticity. The mRLFE incorporated the corneal thickness and posterior fluid-structure interface. Viscoelasticity of the untreated and CXL-treated eyes was quantified at various IOPs. Corneal stiffness increased after CXL and was almost linear as a function of IOP.