Assessment of Biosafety and Implantation Feasibility of Novel Phakic Refractive Lens

Abstract Purpose: To investigate the biosafety and implantation feasibility of newly developed phakic refractive lens (PRL) in rabbit eyes. Methods: The PRLs, including short PRL (S-PRL), large PRL (L-PRL), and large grooved PRL (LG-PRL), were prepared by molding liquid medical silicon. The in vitro cytotoxicity of the above PRLs was evaluated by incubating them with human lens epithelial cells (HLECs) and then measuring cell viability by CCK-8 assay. In vitro cell adhesion of PRLs was assessed by culturing HLECs on PRL film surface and calculating the cell number and average cell area after stained with Calcein-AM and fluorescent. The implantation feasibility was appraised by observing the relative positions of S-PRL, L-PRL or LG-PRL implanted in the posterior chamber of rabbit eyes by optical coherence tomography, and calculating their retention ratio postoperatively. The intraocular pressure (IOP) of S-PRL, L-PRL, LG-PRL and control groups of rabbit eyes was compared to evaluate the biosafety of implantation.Results: The results of in vitro cytotoxicity showed no significant difference of cell viability was observed in the S-PRL, L-PRL or LG-PRL groups compared to the control group throughout the whole experiment. The HLECs cultured on the PRL film surface presented similar cell number, but smaller average cell area (53.8% vs 100%) when compared to the control group, which implied obvious adhesion inhibition on HLECs caused by PRL film. After implantation of S-PRL, L-PRL or LG-PRL into the posterior chamber of rabbit eyes, no obvious inflammation and IOP elevation were observed at each time point in all sample groups compared to the control group, which indicated that PRL samples had good implantation biosafety. Most of the implanted L-PRL and LG-PRL kept in the correct location, while only less of the S-PRL was at the right site. That was, L-PRL and LG-PRL had proper relative position and high retention ratio in the posterior chamber of rabbit eyes. L-PRL and S-PRL samples tended to attach to iris surface, while LG-PRL sample constructed enough space on the iris surface by its grooves surrounding the central optical zone, which was conducive to circulation of aqueous humor.Conclusions: The newly developed LG-PRL sample presented good biosafety in terms of the negligible in vitro cytotoxicity, ocular inflammation and IOP fluctuations. The LG-PRL provided the best implantation feasibility due to the more proper relative position, available space for aqueous humor circulation, and high retention ratio in the posterior chamber of rabbit eyes among the three kinds of PRL samples. Thus, LG-PRL is a promising alternative with appropriate size and surface structure to more effectively correct refractive errors.