Poster Session: Experimental assessment of scleral anisotropy using multi-meridian air-coupled ultrasonic optical coherence elastography

Abstract

Scleral biomechanics plays a key role in the understanding of myopia progression. In this study, we characterized the elastic properties of sclera using an air-coupled ultrasonic (ACUS) optical coherence elastography (OCE) system. New Zealand rabbit eyes (n=7) were measured (<24hr postmortem) in four scleral locations: superior/inferior temporal (ST, IT), and superior/inferior nasal (SN, IN) maintaining an intraocular pressure of 15 mmHg. Elastic waves were induced in the sclera, and wave propagation velocity and shear modulus were measured along two directions: circumferential (superior-inferior) and meridional (nasal-temporal). Wave velocity in scleral tissue ranged from 6 to 24 m/s and shear modulus from 11 to 150 kPa. Velocity was significantly higher (p<.001) in the circumferential vs. meridional directions in the following locations: ST:15.83±2.85 vs 9.43±1.68 m/s, IT:15.00±3.98 vs 8.93±1.53 m/s; SN:16.79±4.30 vs 9.27±1.47 m/s; and IN:13.92±3.85 vs 8.57±1.46 m/s. The average shear modulus in the circumferential was also significantly higher (p<.001) than in the meridional direction for all locations: 65.37±6.04 vs 22.55±1.36 kPa. These results show that the rabbit sclera is mechanically anisotropic with higher rigidity in the circumferential direction compared to the meridional direction. ACUS-OCE is a promising non-invasive method to quantify the biomechanical changes in scleral tissue for future studies involving myopia treatments.

Footnotes

 Funding: Funding: Horizon 2020 Framework Programme European Project Imcustomeye (H2020-ICT-2017 Ref. 779960); European Research Council (2018-ADG-SILKEYE-833106); Spanish Government PID2020-115191RB-I00; NIH NIE P30EY 001319; Unrestricted Funds Research to Prevent Blindness, NY; Spanish Government10.13039/100014440 (CSIC JAE Intro Fellowship); L'Oréal-UNESCO “For Women in Science” Spain; Spanish Government Juan de la Cierva-Incorporation Fellowship (IJC2018-037508-I); Fundacja na rzecz Nauki Polskiej (MAB/2019/12); National Agency for Academic Exchange, Polish Government (NAWA ULAM/2020/1/00176)