A variety of ophthalmic conditions can yield perforations or lacerations of the cornea. Corneal lacerations represent ophthalmic emergencies that if not treated promptly and effectively can lead to blindness. Treatment options for corneal lacerations include suturing, patch grafting, penetrating keratoplasty, keratoprostheses, and biological glues (e.g., cyanoacrylate). Sutureless procedures using biological glues are advantageous since these techniques immediately restore the integrity of the globe and decrease the risk of additional surgical complications. We have synthesized, characterized, and evaluated a novel photocrosslinkable hyaluronic acid-based adhesive for repairing ex vivo and in vivo full thickness corneal lacerations.
A solution of hyaluronic acid was modified with methacrylate groups (HA-MA), precipitated, dried, reconstituted in an aqueous solution, and sterilized before use (see Figures). The viscous polymer solution was applied to 38 of 43 experimental corneal lacerations in rabbits and subsequently irradiated with a low-intensity argon laser beam to produce a clear flexible polysaccharide hydrogel patch. The ability of this sealant to repair corneal lacerations was evaluated in four types of full-thickness 3 mm corneal wounds (linear, linear plus epithelium removed, stellate, and stellate plus epithelium removed). Slit-lamp examinations, measurements of IOP, Seidel tests, and histological studies were performed at selected intervals to evaluate the wound and to determine the rate of healing. Corneal perforations were completely sealed and the anterior chambers had reformed by 6 hours in HA-MA treated eyes. There was no evidence of leakage at this or later times in 37 of the 38 eyes. Intraocular pressure had risen to near normal levels by day 7 in all four groups, and the sealant was still present in most eyes at day 7. In contrast, the anterior chambers did not reform in control eyes (5) with untreated perforations because of aqueous leakage through the wounds. Minimal inflammation was observed clinically or in histological sections of treated corneas. There was extensive proliferation of stromal cells and formation of new extracellular matrix at the wound edges, which became tightly adherent between days 4 and 7.Our novel photocrosslinkable methacrylated hyaluronan polymer sealed 97% (37/38) of the experimental corneal lacerations. HA-MA may prove useful for sealing corneal lacerations in patients as well as for other sutureless ophthalmic surgical procedures.