Perforating eye injuries from external rear vision mirrors.

PURPOSE: To highlight external rear vision mirrors as a cause of ocular injuries in motor vehicle accidents. METHODS: Three cases of perforating eye injuries due to shattered external rear vision mirrors in motor vehicle accidents are described. The relevant Australian design rules are reviewed. RESULTS/CONCLUSION: External rear vision mirrors can be responsible for serious ocular injuries in motor vehicle accidents. Further investigation of the incidence of such injuries is required to determine whether vehicle manufacturing methods and the design rules covering their production warrant revision.

Penetrating eye injuries in rural New South Wales.

PURPOSE: To determine the epidemiology and outcomes of penetrating eye injuries in a rural Australian setting. METHODS: A retrospective study of an 11 year period to identify 77 cases of penetrating eye injury in Lismore, New South Wales. RESULTS: The commonest cause of penetrating eye injury was fencing wire followed by hammering metal. The average age was 32.6 years, and males were involved in 88% of cases. A final visual acuity of 6/12 or better was achieved in 61% of cases. Enucleation was performed in 14%. Visual outcome was best for wounds involving the cornea only. CONCLUSIONS: Penetrating eye injuries are potentially devastating to vision, but with modern surgical techniques patients are likely to achieve reasonable vision. Prevention requires education to ensure adequate protective measures are taken in potentially hazardous settings.

Respiratory enthalpy changes in mine rescue workers exercising under heat stress.

Respiratory enthalpy change, rectal temperature, and heart rate of mine rescue workers exercising at a metabolic energy production rate of 4 met (1 met-58.15 W.m-2) in a 40 degrees C saturated environment, wearing closed-circuit breathing apparatus, were continuously measured in 10 volunteer subjects. The effects of using liquid O2 and compressed O2 apparatus were compared in each subject. Evaporative heat exchange was much greater with the liquid O2 type of apparatus, causing a significantly lower rate of rise of rectal temperature and heart rate. Convective heat exchange was negligible. Mean values for evaporative heat loss (maximum) were 61 +/- 16 (SD) W with liquid O2 and 20 +/- 18 W with compressed O2 (P less than 0.0001, 2-sided t test). Mean values for rectal temperature (rate of increase) were 0.022 +/- 0.009 (SD) degrees C.min-1 for liquid O2 and 0.036 +/- 0.015 degrees C.min-1 for compressed O2 (P less than 0.005, 2-sided paired t test). Mean values for heart rate (rate of increase) were 2.64 +/- 0.74 (SD) min-2 for liquid O2 and 3.27 +/- 0.89 min-2 for compressed O2 (P less than 0.02, 2-sided paired t test). This study quantifies, for the first time, the respiratory enthalpy change in exercising heat-stressed mine rescue workers and shows, from a physiological point of view, that the liquid O2 apparatus is clearly superior to the compressed O2 apparatus.