Title: 3D Monitoring of the Microphase Separations inside the Intraocular Lens

Abstract: Glistenings often occur after implanting the intraocular lens (IOL) due to the formation of numerous mi- crovacuoles (MVs) and may lead to deterioration of vision quality. Previous studies showed the formation of MVs was associated with the hydrophobicity of IOL materials. Yet, the mechanism remains an open question due to the complexity of IOL polymer networks. In this study, two commercialized IOLs with similar hydrophobicity are found distinct in the formation of MVs. The 3D growth kinetics of MVs during cooling processes are captured for the first time by digital holographic microscopy (DHM) and the com- ponents of MVs are measured by DHM and Raman spectroscopy. The results reveal that the growth of MVs stems from the microphase separation of water and surrounding IOL polymers. A polymer swelling model is thus proposed to describe the microphase separation process which is found dependent on the elasticity of IOL polymer networks. The total volume of MVs is determined by the IOL hydrophobicity, while the elastic force of IOL polymer networks determines the number density and size of MVs. This study demonstrates an approach for characterizing the phase separation of crosslinked polymeric mate- rials in biosystems and sheds lights on the refinement of IOL materials.
https://doi.org/10.1016/j.actbio.2024.01.035