Eye injury risk from water stream impact: biomechanically based design parameters for water toy and park design.

PURPOSE: Interactive water displays are becoming increasingly popular and can result in direct eye contact. Therefore, the purpose of this study is to investigate eye injury risk from high speed water stream impacts and to provide biomechanically based design parameters for water toys and water park fountains. METHODS: An experimental matrix of 38 tests was developed to impact eight porcine eyes with water streams using a customized pressure system. Two stream diameters (3.2 mm and 6.4 mm) were tested at water velocities between 3.0 m/s and 8.5 m/s. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve and used to determine the injury risk for hyphema, lens dislocation, retinal damage, and globe rupture for each impact. RESULTS: Experimental water stream impacts created a range of intraocular pressures between 3156 mmHg and 7006 mmHg (61 psi to 135 psi). Injury risk varied between 4.4%-27.8% for hyphema, 0.0%-3.0% for lens dislocation, and 0.1%-3.3% for retinal damage. All tests resulted in 0.0% injury risk for globe rupture. The two water stream diameters did not result in significantly different water stream velocities (P = 0.32); however, the variation in water stream diameter did result in significantly different intraocular pressures (P = 0.03) with higher pressures for the 6.4 mm stream. CONCLUSIONS: This is the first study to experimentally measure intraocular pressure from high speed water stream impacts and quantify the corresponding eye injury risk. It is recommended that toy water guns and water park fountains use an upper threshold of 8.5 m/s for water stream velocities to minimize the risk of serious acute eye damage from impacts.

Evaluating the risk of eye injuries: intraocular pressure during high speed projectile impacts.

PURPOSE: To evaluate the risk of eye injuries by determining intraocular pressure during high speed projectile impacts. METHODS: A pneumatic cannon was used to impact eyes with a variety of projectiles at multiple velocities. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve. A total of 36 tests were performed on 12 porcine eyes with a range of velocities between 6.2 m/s and 66.5 m/s. Projectiles selected for the test series included a 6.35 mm diameter metal ball, a 9.25 mm diameter aluminum rod, and an 11.16 mm diameter aluminum rod. Experiments were designed with velocities in the range of projectile consumer products such as toy guns. RESULTS: A range of intraocular pressures ranged between 2017 mmHg to 26,426 mmHg (39 psi-511 psi). Four of the 36 impacts resulted in globe rupture. CONCLUSIONS: Intraocular pressures dramatically above normal physiological pressure were observed for high speed projectile impacts. These pressure data provide critical insight to chronic ocular injuries and long-term complications such as glaucoma and cataracts.