Investigating scleral crosslinking to stop myopia progression using optical coherence elastography

Scleral collagen crosslinking (SCXL) to mechanically reinforce the scleral tissue and modify axial length is the most promising novel technique to treat Myopia. In this study, we use Optical coherence elastography (OCE) and mechanical testing to evaluate the impact of SCXL on different posterior scleral locations, by quantifying the shear and Young's modulus, to characterize the biomechanical properties of posterior sclera that are better suited for a higher impact of the SCXL. 15 porcine eyes were treated with riboflavin-ultraviolet-A irradiation (UVX-SCXL). Rayleigh-wave speed was measured: (1) before treatment, (2) after 30 minutes soaking on riboflavin, (3) after UVX-SCXL treatment, and (4) after treatment in a non-treated area. Uniaxial tensile tests were performed on scleral strips. Shear and Young modulus were obtained for all conditions. Mean wave speed (WS) and shear modulus (G) for posterior sclera differed statistically for the different locations, being the POST-POST higher than POST-ANT, both in temporal (WS 85% and G ↑124%, p<0.05) and nasal (WS ↑124%, p<0.01 and G ↑160%, p<0.01) positions. UVX-SCXL treatment changed significantly the mechanical properties of posterior sclera, with higher changes induced at the most posterior locations (POST-ANT WS= 22.95±1.15 (m/s) T↑130% N↑146% and POST-POST WS= 26.28±1.41 (m/s) T↑142% N↑132%, p<0.01, averaged across frequencies)). Both shear and Young's modulus significantly increased after treatment (averaged across eyes: G T↑249% N↑193% and E T↑320% N↑208%, p<0.01). OCE is a noninvasive, high-resolution tool to evaluate the impact of SCXL ex vivo, and in vivo in the future. Differences in posterior scleral properties should be considered to maximize the impact of UVX-SCXL treatment. UVX-SCXL in porcine scleras changes significantly the biomechanical properties and strengthen the scleral tissue. Future work will consist on the evaluation of the biomechanical and microstructural changes in posterior sclera following SCXL in myopic eyes.