A recent study found that just because drivers have passed the required vision test, they aren’t necessarily “safe drivers.” According to results of the study, the frequency and distance at which drivers, with moderate levels of cataracts and blurred vision, recognize pedestrians during nighttime hours was severely reduced, regardless of whether or not the driver had passed the designated vision exam.

As anyone who has passed the NBEO Applied Basic Science Exams would know, cataracts can cause blurred vision and other vision side effects. Many drivers continue to drive with these conditions and don’t realize that driving with blurred vision could result in fatal injuries.  According to Joanne Wood, author of the study and member of the School of Optometry and Vision Science and the Institute of Health and Biomedical Innovation at Queensland University of Technology, the study was performed with multiple goals in mind.

In addition to understanding the effects of cataracts on nighttime vision, researchers and doctors performing the study also hoped to see if certain types of pedestrian clothing could improve the visibility of the pedestrians to drivers suffering from blurred vision or nighttime vision loss. The study took 28 young adult licensed drivers who satisfied Australia’s minimum of 20/40 or better vision for driving and used them to measure a driver’s ability to recognize pedestrians against stimulated headlight glare.

The participants drove at night on a closed circuit while wearing reflective blur and cataract lenses. The “pedestrians” were dressed in three outfits: all black, all black with a reflective vest, and all black with reflective gear on their wrists, elbows, ankles, shoulders, knees and waist. The findings of the study were conclusive and showed that cataracts are significantly more disruptive than blurred vision.

Drivers with simulated blurred vision reported seeing pedestrians 52.1 percent of the time, while participants with stimulated cataracts only reported seeing pedestrians 29.2 percent of the time. The results are alarming, especially considering that those with cataracts drive regularly. Countless individuals rarely visit an optometrist and may not even know if they are suffering from cataracts.

In addition to not seeing the pedestrians at all, when the blurred vision and cataract stimulated drivers did report seeing pedestrians, they were seen at much closer distances. Those with normal vision reported seeing pedestrians at longer distances: sometimes close to four times longer than those with blurred vision and five times longer than those with cataract induced vision.

According to researchers, further research is definitely required in this area, and for those who do suffer from cataracts, surgery should be done early enough to avoid potentially dangerous driving conditions.