Posted December 12, 2017

Mark S. Humayun, M.D., Ph.D., University of Southern California
Jack Whalen, Ph.D., University of Southern California
Mark Thompson, Ph.D., University of Southern California

It is estimated that from 2002 through 2007, 13% of military personnel evacuated from Iraq and Afghanistan suffered a combat-related ocular injury.¹ Of all ocular injuries reported in Operation Iraqi Freedom (OIF) from 2003 through 2005, 55% of those requiring specialized ophthalmic care were open-globe injuries.² Open globe injuries cause a drop in intraocular pressure (IOP) and expose the eye to potential pathogens; both situations can lead to vision loss if left untreated for more than 24 hours. In combat scenarios the availability of a trained ocular surgeon and/or the necessary tools to perform the surgery to repair the damage may be limited due to location or mass casualty events. Currently, ophthalmologists treating open globe injuries must use microsurgical instruments and microscopes to carefully close the globe, instruments which are unavailable to combat medics in austere environments. As such, the standard of care is to shield the eye and wait for transportation to a full service base or hospital, which can often take days; at which point the vision loss is irreversible. It has also been reported that visual outcomes for ocular trauma patients decrease with increasing time to intervention. Therefore, developing easy-to-use technologies may help with temporary closure of the globe and thus improve visual outcomes for ocular trauma victims.

With support from a Fiscal Year 2015 (FY15) Joint Warfighter Medical Research Program (JWMRP) contract, the University of Southern California's (USC) team led by Dr. Mark Humayun, sought to build upon a first generation ocular adhesive system developed through an FY11 Vision Research Program (VRP) award. With the FY15 JWMRP contract, Dr. Humayun aims to develop a second generation reversible adhesive patch, called Scleropatch Hydrogel Ocular Repair System (SHORS)�, which could be easily placed in the eye to temporarily stabilize combat-related penetrating eye injuries in wounded Service members. The technology is being developed in collaboration with Dr. Mark Thompson from the Department of Chemistry at (UCS's) Dornsife College of Arts and Letters.

The technology developed by the USC team is a two-part system consisting of a reversible adhesive and an injector tool to deploy the adhesive. The first part of the system is a thermo-responsive hydrogel that, when cold, absorbs water becoming fluid-like and injectable; but when heated to body temperature, it dehydrates and becomes sticky like chewing gum. Once in place, the eye is temporarily stabilized until the Service member is able to be evacuated to a military treatment facility for further medical attention. Once a surgeon is ready to fully repair the open globe injury, the hydrogel is able to be removed through the introduction of cold water which rehydrates the gel and converts it back to its fluid state.

The second part of the system is a disposable injector tool which allows the hydrogel to be carried in a lightweight disposable syringe-like device. When needed, the tool can be activated to rapidly cool the hydrogel (like cracking a glow stick), giving the user a 10-minute window to inject the hydrogel. Once used the tool can be thrown away. The total system takes up no more space than a 15cc syringe, making it easily deployable.

In May 2017, a team of investigators from the USC's Institute for Biomedical Therapeutics and Roski Eye Institute of the Keck School of Medicine hosted a small breakout workshop at the 2017 US Army's Annual Tri-Service Ocular Trauma Workshop at the Walter Reed National Military Medical Center. The purpose of the workshop was to test novel medical technology for temporary treatment of open globe injuries of the eye. Over the course of the four-day Trauma Surgery Lab, 44 individuals including military ophthalmologists, medics, corpsmen, neurosurgeons, and researchers tested the new technology in a benchtop model of ocular trauma and provided valuable feedback which will be used by the USC team to further accelerate their technology towards clinical trials.

The visiting team, led by USC Assistant Professor of Ophthalmology Research, Jack Whalen, brought 144 disposable injector tools each loaded with the novel, SHORS, hydrogel. The objective was to capture user feedback from service men and women who see and treat open globe injuries. Each tester was invited to try to seal a full-thickness laceration through the wall of a benchtop model of an open globe injury. Afterwards, each tester was invited to fill out a brief questionnaire to capture their impressions of the concept as well as provide any suggestions or improvements that might be helpful to consider in the final design. Of those who completed the questionnaire, 94% thought the SHORS for open globe injuries was feasible and, remarkably, 94% of responder said they could envision the system being used in the field or in managing combat casualties. Although, 63% of the responders found the color change from transparent to white was useful, 86% recommended having the color change to a more visible color, such as blue.

In a 2003 Centers for Disease Control and Prevention report, it was estimated that visually impaired individuals incur an average $566,000 of additional lifetime costs associated with medical and non-medical support. Therefore, investing in the development of next-generation technologies that may improve visual outcomes for combat casualties sustaining ocular injuries is of vital importance for current and future combat situations. By having a deployable, easy to administer �glue� that is able to close open globe injuries until the Service member can reach definitive care will lead to improved visual outcomes and ultimately prevent blindness and visual impairment for both our service men and women as well as civilian combat casualties and civilians in general.

References:

1. E.D. Weichel, M.H. Colyer, S.E. Ludlow, et al. Combat ocular trauma visual outcomes during operations Iraqi and Enduring Freedom. Ophthalmology. 2008 Dec; 115(12):2235-45.
2. R.I. Cho, E. Savistky. Combat Casualty Care. Lessons Learned from OEF and OIF. Editors E. Savitsky, B. Eastridge. Pelagique LLC and the Borden Institute. Office of the Surgeon General. Ocular Trauma: Chapter 7. 2012.

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