"Johnny Poppers": a cause of serious ocular injury. Issue 7 (1st July 1998)

• Record Type: Journal Article
• Authors: MacAndie, Kerr; Kyle, Peter
• Is Part Of: British journal of ophthalmology. Volume 82:Issue 7(1998)
• Page Start: 807
• Page End: 809
• Publication Date: 1998-07-01
• Subjects: ocular trauma -- projectiles; Ophthalmology -- Periodicals; 617.7
• DOI: 10.1136/bjo.82.7.807
• Languages: English
• ISSNs: 0007-1161

Abstract

Abstract : AIMS/BACKGROUND: The causes of blunt ocular trauma are many and diverse. We present two cases of ocular injury caused by an unusual form of weapon called a "Johnny Popper". There follows a theoretical and experimental evaluation of the velocity of the projectiles fired by this device. METHODS: A Johnny Popper was constructed under expert guidance. The elastic properties of the device were measured and this allowed calculation of a theoretical exit velocity of the projectiles fired. The weapon was subsequently fired under test conditions which permitted the exit velocity of the projectiles fired to be measured directly. RESULTS: The theoretical velocity of the projectiles was calculated as 80 ms -1 and the experimentally measured velocity was 57 ms -1 . CONCLUSIONS: Johnny Poppers are a previously undescribed and unique form of home made weapon. They are intended for playful mischief, but have the potential to cause serious ocular trauma.