Abstract
Purpose: :
A simulation model of the human eye which we have developed was applied to simulated airbag ocular injury, to determine the physical and mechanical conditions of an impacting airbag that would cause globe rupture in an eye with a transscleral-fixed posterior chamber IOL.
Methods: :
Simulations were performed with a computer using the finite element analysis program PAM-CRASHTM (Nihon ESI, Tokyo, Japan). The airbag was set to impact on the surface of an eye with a transscleral-fixed posterior chamber IOL at various impact velocities. The limit of tensile force of a 10-1 polypropylene suture was assumed to be 0.16 N, which is specified in the U. S. Pharmacopeia (USP) XXII.
Results: :
Although at the lowest velocity of 20.0 m/sec, it was considered that 10-0 polypropylene sutures were unlikely to break, sutures fixing the IOL might be broken and a corneoscleral incision was likely to open after 0.3 sec at the medium impacting velocity (30 m/sec). Suture rupture was very likely to occur at the high velocity (40 m/sec), since the tensile force on sutures continuously exceeded the breaking force after the impact.
Conclusions: :
These results suggest that severe ocular trauma can be caused in an eye with a transscleral-fixed posterior chamber IOL by an airbag at high impact velocity. Therefore, it should be noted that small individuals such as elderly women are at greater risk of airbag ocular injury. Further research on modification of airbag design and deployment to minimize the risk of ocular injury is important.
Keywords: trauma • intraocular lens • computational modeling