A mathematical model of drug delivery via a contact lens during wear

Contact lenses have been studied as a potential method of ophthalmic drug delivery since at least the 1970s, but no therapeutic option has been marketed to date. Barriers to commercial implementation include lack of in vivo and in vitro studies, and the absence of a complete understanding of the underlying fluid dynamics. To join theoretical and experimental information, we design a compartmental model of contact lens drug delivery to align with an in vitro model eye system. The model couples a partial differential equation for linear diffusion of drug inside the contact lens with ordinary differential equations governing the dynamics of the pre- and post-lens tear films and the eyelid region. The model simulates tear film dynamics during blinking over multiple hours. We compute the cumulative amount of drug released from the contact lens and compare our results to experimental model eye data. By isolating certain mechanisms or combinations of mechanisms in our model during this comparison, we attempt to better understand the mechanics of contact lens drug delivery.