Eye Injuries from Airbags with Seamless Module Covers

Abstract

Air bag deployment through a seamless module cover may release foam particles at high velocities that could result in eye injuries. This paper presents the results of twenty-one (n = 21) tests in which foam particles, similar to those observed from air bag deployments, were impacted onto porcine eyes. A pneumatic cannon was designed to propel the foam disks at speeds representative of actual foam particle velocities as observed in prototype air bag deployments. Five foam types, which varied in density and stiffness, were used. All tests were recorded with high speed video (1000 fps). The mass of the impacting particles varied from 0.155 g to 0.653 g with velocities from 18 m/s to 87.6 m/s. Injury analysis was performed using three techniques: fluorescein dye to reveal corneal abrasions, ophthalmic ultrasound to determine lens displacements and retinal detachments, and necropsy to examine tissue damage. As seen in case reports of air bag induced eye injuries, corneal abrasions were the most recorded injuries in the porcine eye impact tests. A logistic regression analysis demonstrated that the combination of mass and velocity in the form of kinetic energy was the most significant contributor to injury (p = 0.0023). An injury risk curve was generated based on kinetic energy which gave a 50% risk of corneal abrasion at 0.183 J. Over the range of materials used, the foam type was a poor contributor to the model (p = 0.45). The injury risk function presented for the kinetic energy of the particles offers a design guide to minimize corneal abrasions, if the production of foam particles during air bag deployment is unavoidable. Air bag designs have traditionally had the air bag deploy through a door that contains a seam to separate it from the dashboard ( Figure 1a). A recent trend has emerged in which the door is removed and the air bag is placed behind a seamless panel (Figure 1b). While this trend currently focuses on passenger side air bag systems, the seamless design may be applied to driver side modules as well. In automobiles with the seamless design, the air bag tears through a scored section of the dashboard. During the air bag deployment process, it is possible for foam particles from the dashboard to be released at high velocities. The particles may vary in size and velocity depending on the type of foam used in the dashboard, design of the air bag, and the ambient temperature. With the introduction of seamless module covers, an additional risk of ocular injury is presented by the foam particles that does not require direct contact with the air bag. The goal of this study is to minimize the risk of ocular injury from the foam particles by establishing an injury criteria for use in developing seamless air bag covers.

Effects of Bracing on Human Kinematics in Low-Speed Frontal Sled Tests

“…The number of occupants sustaining injuries greatly exceeds fatalities in magnitude as 931,000 are injured in frontal collisions. 47 Injuries sustained in motor vehicle collisions range from extremity [20][21][22]28,29,39,42 and eye [23][24][25]27 injuries, to more serious head 17 and chest 26,34,40,41 injuries. The total economic cost incurred as a result of motor vehicle collisions in 2000 totaled $230.6 billion.…”

Dynamic material properties of the human sclera

“…In 2007, approximately 66,000 people suffered from vehicle-related eye injuries in the United States (Mcgwin et al, 2005). Of the vehicle occupants sustaining an eye injury during a crash, as many as 15-25% sustain severe eye injuries (Duma and Crandall, 2000;Duma et al, 2002) and it was shown that within these severe eye injuries as many as 45% resulted in globe rupture (Kuhn et al, 1994).…”

Airbags

“…However, it has been shown that airbags cause potential hazards to children [272] and small stature occupants in the front seat [273,274]. The other airbag injuries to adult occupants include periorbital fracture, head injuries, eye injuries [275,276], internal organ lacerations, cervical spine injuries and otologic injuries [277]. In addition to the minor and severe injuries, deaths of adult occupants have also been reported.…”

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