title: Differentiating untreated and cross-linked porcine corneas of the same measured stiffness with optical coherence elastography.
abstract: Structurally degenerative diseases, such as keratoconus, can significantly alter the stiffness of the cornea, directly affecting the quality of vision. Ultraviolet-induced collagen cross-linking (CXL) effectively increases corneal stiffness and is applied clinically to treat keratoconus. However, measured corneal stiffness is also influenced by intraocular pressure (IOP). Therefore, experimentally measured changes in corneal stiffness may be attributable to the effects of CXL, changes in IOP, or both. We present a noninvasive measurement method using phase-stabilized swept-source optical coherence elastography to distinguish between CXL and IOP effects on measured corneal stiffness. This method compared the displacement amplitude attenuation of a focused air-pulse-induced elastic wave. The damping speed of the displacement amplitudes at each measurement position along the wave propagation were compared for different materials. This method was initially tested on gelatin and agar phantoms of the same stiffness for validation. Consequently, untreated and CXL-treated porcine corneas of the same measured stiffness, but at different IOPs, were also evaluated. The results suggest that this noninvasive method may have the potential to detect the early stages of ocular diseases such as keratoconus or may be applied during CLX procedures by factoring in the effects of IOP on the measured corneal stiffness.
authors.affiliation: University of Houston, Department of Biomedical Engineering, 3605 Cullen Boulevard, Room 2027, Houston, Texas 77204, United States.
authors.forename: Jiasong
authors.initials: J
authors.lastname: Li
authors.affiliation: University of Houston, Department of Biomedical Engineering, 3605 Cullen Boulevard, Room 2027, Houston, Texas 77204, United States.
authors.forename: Zhaolong
authors.initials: Z
authors.lastname: Han
authors.affiliation: University of Houston, Department of Biomedical Engineering, 3605 Cullen Boulevard, Room 2027, Houston, Texas 77204, United States.
authors.forename: Manmohan
authors.initials: M
authors.lastname: Singh
authors.affiliation: University of Houston, College of Optometry, 4901 Calhoun Road, Houston, Texas 77204, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Twa
authors.affiliation: University of Houston, Department of Biomedical Engineering, 3605 Cullen Boulevard, Room 2027, Houston, Texas 77204, United StatescBaylor College of Medicine, Department of Molecular Physiology and Biophysics, One Baylor Plaza; Room 414B, Houston, Texas 7.
authors.forename: Kirill V
authors.initials: KV
authors.lastname: Larin
mesh_terms: D000818:Animals; D003315:Cornea / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*; D003432:Cross-Linking Reagents / Q000494:pharmacology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D007429:Intraocular Pressure / Q000502:physiology; D061848:Optical Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D013552:Swine
chemical_list: D003432:Cross-Linking Reagents