Effect of time and temperature-dependent changes of IOL material properties on IOL: Lens capsule interactions

Posterior Capsule Opacification (PCO) is the most common complication associated with Intraocular Lens (IOL) implantation. Based on the assumption that the interactions between an IOL and the lens capsule (LC) may influence the extent of PCO formation, a new in vitro model was developed to quantify the adhesion force of an IOL to simulated LC using a custom-designed micro-force tester. Using this system, we examined the influence of temperature (room temperature vs. body temperature) and incubation time (0 vs. 24 h) on the adhesion force between IOLs and LCs. The results show that, in line with clinical observations of PCO incidence, the adhesion force increased at body temperature and with increase in incubation time in the following order, Acrylic foldable IOLs > Silicone IOLs > PMMA IOLs. By examining the changes of surface properties as a function of temperature and incubation time, we found that acrylic foldable IOLs showed the largest increase in their hydrophilicity and reported the lowest surface roughness in comparison to other IOL groups. Coincidentally, using a newly established macromolecular dye imaging system to simulate cell migration between IOLs and LC, we observed that the amount of macromolecular dye infiltration between IOLs and LCs was in the following order: PMMA IOLs > Silicone IOLs > Acrylic foldable IOLs. These results support a new potential mechanism that body temperature, incubation time, surface hydrophilicity and smoothness of IOLs greatly contribute to their tight binding to LCs and such tight binding may lead to reduced IOL: LC space, cell infiltration, and thus PCO formation.