Contact lenses aren’t often thought of as devices that can combat disease. In fact, they’re more often blamed for contributing to conditions ranging from dry eye to infectious keratitis. But researchers at the University of New Hampshire are currently experimenting with a hydrogel lens they created to treat corneal melting—a significant cause for blindness with no cure.
Corneal melting is caused by excessive expression of zinc-dependent matrix metalloproteinases (MMPs). This overabundance of MMPs leads to uncontrolled degradation of cellular and extracellular components of the cornea. The technology the researchers are working with uses a hydrogel formulated to deactivate the MMPs, ideally slowing the progression of corneal melting.
The team’s research paper, published in ACS Biomaterials Science & Engineering, explains that the lens is made of typical poly(2-hydroxyetyl methacrylate) (pHEMA) material with the addition of dipicolylamine (DPA), which has high affinity and selectivity for zinc ion. As a result, the lens selectively removes zinc ions from a physiological buffer and deactivates MMP-1, MMP-2 and MMP-9 within two hours of insertion when tested on in vitro and ex vivo porcine corneas, the researchers explain in their paper. The hydrogel does not affect the viability of keratocytes and corneal epithelial cells.
Unlike conventional MMP inhibitors, this hydrogel lens minimizes the risk of serious, nonspecific side effects and provides a method to slow down the progression of corneal melting and other related ocular diseases, the researchers say.
|Lopez C, Park S, Edwards S, et al. Matrix metalloproteinase-deactivating contact lens for corneal melting. ACS Biomaterials Science & Engineering. 2019;5(3):1195-9.|