Experimental techniques for measuring the biomechanical response of the eye during impact

Over 2 million eye injuries occur each year in the United States as a result of trauma. In order to show the injury potential of objects such as BB guns, paintball guns, automotive airbag systems, and other consumer products, researchers have frequently tested enucleated eyes which have been placed in simulated orbits and held in place with a 10% gelatin solution. The purpose of this study is to perform biomechanical impact tests using both in-situ human eyes and human eyes mounted in simulated orbits, to compare the responses of both. A total of 12 dynamic eye impact tests were performed to develop force-deflection characteristics of the human eye in-situ, determine the effects that the extraocular muscles have on the response of the eye to dynamic impacts, and to characterize the force-deflection response of eyes supported with a gelatin solution within a simulated orbit. It was found that force-deflection corridors are similar with the extraocular muscles left intact or transected. Impact tests performed on eyes mounted in simulated orbits made of polycarbonate and filled with a 10% gelatin solution showed force-deflection responses that matched those of the in-situ eye impact tests. It is concluded that the use of simulated orbits to perform eye impact tests offers the appropriate boundary conditions to represent the in-situ human eye under dynamic eye impact events.