June 19, 2013
Eye PATCH: Visualizing the Future of Injury Treatment
Eye injuries on modern battlefields are becoming more and more common due to shrapnel and sand particles swirling in the air as the result of explosions. Scratches, lacerations, and penetrating injuries can be very painful, impair vision, and render a soldier unable to function for several days.
Scientists at APL have teamed up with The Johns Hopkins University School of Medicine and the Wilmer Eye Institute as part of the Eye PATCH project to create three materials that help repair soldiers’ eye injuries. The project is sponsored by the U.S. Army Medical Research and Materiel Command.
“While the majority of injuries that affect only the eye’s surface will eventually heal without permanent loss of vision, there is a significant risk of secondary infections and corneal scarring—particularly in the battlefield environment,” says Morgan Trexler, the Research and Exploratory Development Department’s (REDD’s) Eye PATCH project manager.
Treatments that are effective in a civilian setting—such as emergency fittings of a soft contact lens over the injured eye—are not practical for a combat environment. “Ideally, any eye bandage should have material properties similar to those of contact lenses, while promoting wound healing and providing sustained delivery of pharmaceuticals. “The ability to be applied in the field by medical corpsmen is critical,” says Trexler.
The team’s first product is like an adhesive bandage for the eye—something that a soldier can keep in a backpack and apply after getting a scratch from sand, for example. This cellulose bandage, currently being tested for toxins and biocompatibility, is made to protect the eye from more injury and releases antibiotics to prevent infection.
An Independent Research and Development project using cellulose for a completely different application sparked the idea to use it for the bandage.
“We are using cellulose because it is a natural polymer with unique moisture-management capabilities,” says Marcia Patchan, supervisor of REDD’s Chemistry Section. “Cellulose-based polymers are ideal for this use because they can absorb moisture from a wound and can also donate moisture. Keeping wounds moist helps them heal faster.” The ultimate goal is for cellulose bandages to be used in the field as a temporary dressing that will protect the eye tissue from further damage and deliver pain medication and antibiotics until the soldier can receive treatment in a clinic.
The Eye PATCH team is working on a second material—a gel-like substance called a collagen reconstructive membrane—that is designed to repair even more serious injuries that may require the replacement of eye tissue. Collaborators at JHU started to use the material for ocular applications, even though it was originally developed by a group in Japan for other uses. The gel, made from the same material that makes up the outer surface of the eye, can be implanted in the eye to help it heal. While it is being tested for compatibility, APL is also doing modeling to better understand how light scatters through the materials.
“We are studying the optical, mechanical, and thermal properties and [the] structure of the material,” says Xiomara Calderon-Colon, also of REDD. “One of the most interesting things we are seeing is how synthesis parameters—such as temperature, humidity, and time settings which are used to prepare the collagen gels—affect the material’s properties.”
The third material is an eye glue that will render stitches a thing of the past. The adhesive is strong, portable, and easy for a nonexpert to apply to penetrating eye wounds of different sizes. APL scientists are working closely with JHU School of Medicine collaborators like Jennifer Elisseeff, a professor from JHU’s Wilmer Eye Institute and Department of Biomedical Engineering, who is leading work on the adhesives component. “Adhesives that incorporate a biological component can guide tissue regeneration and prevent scar formation, which can have a significant impact on sight,” says Elisseeff.
“Despite our countermeasures, our adversaries are deploying improved improvised explosive devices. Eye injuries inflicted by these devices continue to take their toll on warfighters,” says Charles Goldblum, REDD business area executive.” The Eye PATCH developments will help improve the medical outcomes associated with eye injuries.”