[Utility of dynamic pupillometry in alcohol testing on drivers]

Pupillometry is becoming a relevant tool in Vision Sciences. So far, only a few studies have explored the relationship between pupil reflex measures and drug consumption. The aim of this study was to assess the applicability of dynamic mesopic pupillometry as an objective measurement method for the detection of blood alcohol levels above the legal limit. In a quasiexperimental design, 19 volunteers were asked to participate in two conditions (before and after alcohol intake). In session with alcohol intake, participants were asked to consume 27.5 ml of alcohol in 60 minute intervals for four hours. Pupillometry records were conducted by means of the Power Refractor II, using four types of light stimulation: white (5600 K), blue (450 nm), green (510 nm) and red (600 nm). The basal diameter of the pupil increased significantly for alcohol concentrations equal to or greater than 0.25 mg/l in exhaled breath. Moreover, the value of the amplitude for red light constriction also provided significant differences between the two conditions. These results are promising in the search for new methods to detect illegal alcohol levels among drivers. This study demonstrates that basal pupil diameter increase and amplitude response could be used as an alcohol consumption level indicator. However, further studies are necessary to validate this and other diagnose methods complementary to breathalyzer and other drugs tests.