Inflation Response of Peripapillary Retina during Acute Intraocular Pressure Elevation
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Date
2021-04
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Abstract
Purpose: In the disease of glaucoma, elevated intraocular pressure (IOP) may mechanically damage retina tissue leading to vision loss. The mechanical deformation of retina during IOP elevations have not been well-characterized. We aim to characterize the peripapillary retina (PPR) deformation during IOP elevation in human donor eyes using high-frequency ultrasound elastography. Methods: Whole globe inflation was performed in ten donor eyes (age: 20-74 years old) while IOP was raised from 5 to 30 mmHg. High-frequency ultrasound scans of the posterior eye centered at the optic nerve head (ONH) were collected during inflation. A correlation-based speckle tracking algorithm was used to compute displacements, and tissue strains were calculated using least-squares estimation. Radial, tangential, and shear strains were mapped for manually segmented regions of interest (PPR and peripapillary sclera (PPS)). Results: Our results showed that PPR experienced high shear strain, less radial strain, and low tangential strain at 30 mmHg. Localized high shear and tangential strains were present throughout PPR. In comparison to PPS, PPR had greater shear, less radial compression, and similar levels of tangential stretch. Conclusion: Peripapillary retinal damage is characteristic of glaucoma progression. Our findings suggest that although PPR experienced minimal radial compression during IOP elevation, high shear could contribute to mechanical damage of neural tissue during IOP elevation. These results provide new insights into IOP-related mechanical insults on neural tissue near the ONH, where glaucomatous damage initiates.
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Engineering: 2nd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)
Keywords
Glaucoma, Ocular biomechanics, Retina, High-frequency ultrasound, Elastography