Purpose:
Eye trauma results in 30,000 cases of blindness each year in the U.S. and is the second leading cause of monocular visual impairment. Eye injury is caused by a wide variety of projectile impacts and loading scenarios with common sources of trauma being motor vehicle crashes, military operations, and sporting impacts. The purpose of the current study was to computationally model experimental eye impact tests in the literature to analyze global and localized responses of the eye to a variety of blunt projectile impacts.
Methods:
Simulations of 79 experimental tests were run with 8 different projectiles (airsoft pellet, baseball, BB, blunt impactor, paintball, aluminum, foam, and plastic rods) to characterize effects of the projectile size, mass, shape, material, and velocity on eye response. This study presents a matched comparison of experimental test results and computational model outputs including stress, energy, and pressure used to evaluate risk of globe rupture.
Results:
Globe rupture was predicted with stresses exceeding 17 MPa and internal pressures exceeding 1.0 MPa in the simulations. The computational results agreed strongly with the experimental results with a specificity of 0.92 and a sensitivity of 1. Peak stresses were located at the center of the cornea, the limbus, or the equator depending on the projectile type. Area-normalized kinetic energy was the single best projectile predictor of peak stress and pressure. Additional incorporation of a relative size parameter relating the projectile area to the eye area reduced stress response variability and may be of importance in eye injury prediction.
Conclusions:
Stress and pressure response of the eye was determined through computational modeling of a variety of projectiles and loading conditions.
Keywords: trauma • computational modeling • sclera