Pupil tests on drivers called into question

A multimillion pound Department for Transport (DfT) campaign to show how pupil size can reveal drug use in drivers has been launched despite a DfT report recommending that pupillary tests by police be discontinued.

The 2004 Road Safety Research Report to monitor the effectiveness of UK Field Impairment Tests (FIT) said that examination using a pupillometer 'contributed very little' to FIT and overall accuracy was low.

Drugs such as opiates are known to cause pupil constriction whereas cannabis, hallucinogens and stimulants are known to cause pupil dilation. Despite its own report's recommendation to discontinue pupillary tests, the DfT believes its £2.3m campaign (News 21.08.09) will be effective. 'The pupil testis used along with a range of other measures precisely because pupil dilation can be caused by a number of things. However, although drugs are not the only factors to have an involuntary effect on the eyes they are one of the signs that the police can look for,' said a spokesperson. 'The reason that we use this as the focus for the campaign is that this effect on the eyes is well known among drug users but they don't think that enforcement authorities know about it. Our research showed that the target audience was very responsive to this message.'