Abstract
Purpose: :
To test the hypotheses that specific times of day pose disproportionate risk for open globe trauma in 5 circumstances: (1) construction work, (2) intentional trauma, (3) motor vehicle collisions, (4) students and (5) small children.
Methods: :
Retrospective cross–sectional study. Cases from 1999–2005 were selected randomly from records of the MEEI Trauma Service. The inclusion criterion was any new open globe injury. Exclusion criteria were (1) history of prior intraocular surgery on the involved eye and (2) essential information missing from the chart. Cases were classified by patient descriptors, occupation, mechanism, intentional vs. unintentional, and time of day. Time of day was sorted into 8 bins of 3 hours each. For each hypothesis, Fisher’s exact test was used to compare different time periods for: (1) cases of interest vs. all other cases; and (2) cases of interest vs. a random model based on equally distributed risk all hours of the day.
Results: :
From over 300 records reviewed, 101 met study criteria. Records excluded on the basis of missing information (n = 38) did not differ from study records with respect to patient descriptors or mechanism. Construction work (machine work and car repair included) accounted for 38% of open globe injuries, which were more frequent between noon and 6 PM despite equal work hours in AM vs. PM (p < 0.01 vs. non–construction; p < 0.05 vs. random model). The relative risk for construction workers (PM vs. AM) was 2.1. Intentional trauma accounted for 11% of cases, with incidents concentrated between 9 PM and 6 AM (p < 0.0001 vs. unintentional; p = 0.10 vs. random model). Motor vehicle collisions (8% of cases) were more common between midnight and 6 AM (p < 0.01 vs. non–MVC; n.s. vs. random model). Students were involved in 14% of cases, more frequently between 9 PM and midnight (p < 0.0001 vs. non–students; p < 0.05 vs. random model). Trauma to small children (n = 8) was evenly distributed over the daytime hours.
Conclusions: :
It is well known that construction workers, carpenters, mechanics, and machinists face disproportionate occupational risk for open globe injury. This study demonstrates that such risks are particularly pronounced in the afternoon. We postulate that this is due to fatigue or postprandial effects, which may influence attentiveness or voluntary use of safety glasses. The results imply a need for more intense workplace surveillance and intervention between noon and 6PM. Other temporal risks identified by this study (intentional trauma, MVC, and students) involve complex social factors, which have already become the focus of prevention endeavours.
Keywords: trauma • clinical (human) or epidemiologic studies: risk factor assessment