Prevention of ocular gunshot injuries using polycarbonate lenses.

Two patients lost three eyes, and one his life, secondary to ocular gunshot wounds. In both patients, the pellets gained entry into the central nervous system through the eye and orbital bones despite only superficial wounds to other areas of the body. These tragic injuries prompted a study of polycarbonate lenses to determine their effectiveness in preventing small caliber ocular gunshot wounds. This investigation determined that 3.0 mm and the 2.2 mm polycarbonate lenses could prevent such injuries at distances greater than 15 yards. In comparing the two lenses, it was found that the 3.0 mm lens sustained less damage at 70 degrees F, but the 2.2 mm lens was more resistant to penetration at 32 degrees F. Since most hunting is done in the fall and winter months, the brittle nature of the thicker lens is significant. Polyamide sports frames with a posterior rim were also tested and found to prevent posterior lenticular expulsion at 15 yards. Standard acetate frames were shown to be ineffective in this regard at 30 yards.