Dynamic Optical Coherence Elastography of the Anterior Eye: Understanding the Biomechanics of the Limbus
Autor: | Achuth Nair, Michael D. Twa, Salavat Aglyamov, Kirill V. Larin, Fernando Zvietcovich, Manmohan Singh |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
Materials science
genetic structures Wave propagation Finite Element Analysis Sus scrofa Limbus Corneae 01 natural sciences Models Biological biomechanics 010309 optics Cornea 03 medical and health sciences Optical coherence elastography Tonometry Ocular 0302 clinical medicine Optical coherence tomography Anterior Eye Segment 0103 physical sciences medicine Animals Elasticity (economics) Intraocular Pressure optical coherence elastography medicine.diagnostic_test limbus Biomechanics eye diseases Elasticity Sclera Biomechanical Phenomena medicine.anatomical_structure 030221 ophthalmology & optometry Elasticity Imaging Techniques sense organs Phase velocity Tomography Optical Coherence Biomedical engineering |
Zdroj: | Investigative Ophthalmology & Visual Science |
ISSN: | 1552-5783 0146-0404 |
Popis: | Purpose Currently, the biomechanical properties of the corneo-scleral limbus when the eye-globe deforms are largely unknown. The purpose of this study is to evaluate changes in elasticity of the cornea, sclera, and limbus when subjected to different intraocular pressures (IOP) using wave-based optical coherence elastography (OCE). Special attention was given to the elasticity changes of the limbal region with respect to the elasticity variations in the neighboring corneal and scleral regions. Methods Continuous harmonic elastic waves (800 Hz) were mechanically induced in the sclera near the corneo-sclera limbus of in situ porcine eye-globes (n = 8). Wave propagation was imaged using a phase-sensitive optical coherence tomography system (PhS-OCT). The eyes were subjected to five different IOP-levels (10, 15, 20, 30, and 40 mm Hg), and spatially distributed propagation velocities were calculated along corneal, limbal, and scleral regions. Finite element analysis (FEA) of the same regions under the same excitation conditions were conducted for further validation of results. Results FEA demonstrated that the stiffness of the heterogeneous cornea-limbus-sclera transition can be characterized by phase velocity measurements of the elastic waves produced at 800 Hz in the anterior eye. Experimental results revealed that the wave speed in the limbus (cL = 6.5 m/s) is between the cornea (cc = 2.9 m/s) and sclera (cs = 10.0 m/s) at a physiological IOP level (15 mm Hg) and rapidly increases as the IOP level is increased, even surpassing the wave speed in the sclera. Finally, the change in elastic wave speed in the limbus (ΔcL∼18.5 m/s) was greater than in the cornea (Δcc ∼12.6 m/s) and sclera (Δcs∼8.1 m/s) for the same change in IOP. Conclusions We demonstrated that wave-based OCE can be utilized to assess limbus biomechanical properties. Moreover, experimental evidence showed that the corneo-scleral limbus is highly nonlinear compared to the cornea and sclera when the eye-globe is deformed by an increase of IOP. This may suggest that the limbus has enough structural flexibility to stabilize anterior eye shape during IOP changes. |
Databáze: | OpenAIRE |
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