EyeWorld Asia-Pacific September 2011 Issue

September 2011 19 EW FEATURE of the blue light-filtering lens as a means to help reduce the effects of glare on driving, especially in those who are particularly bothered by glare. “In our first study and also in this study we noticed that there’s a very large inter-subject variability in glare susceptibility,” Dr. Gray said. “Some people it doesn’t bother at all and others are really incapacitated.” He thinks that those who are susceptible might do better with a blue light-filtering lens. “Especially for those who have trouble with glare, who don’t like driving at night or in the sun, this is a possible means to help,” Dr. Gray said. EW Editors’ note: This study was supported by Alcon, but Dr. Gray has no financial interests related to his comments. Contact information Gray: 44(0) 121 414 7239, r.gray.2@bham.ac.uk environment and came up to signaled intersections and in almost all cases, there was an oncoming vehicle,” Dr. Gray said. “Their task was to try to turn in front of the vehicle if it was safe.” What investigators did was set up the approaching vehicles so that some times it was safe to make the turn. “We forced the person to make a decision,” Dr. Gray said. “We presented conditions where we have a glare source turned on so that it’s simulating the sun pointing in their face while they drive, and we alternate that with conditions where there’s no glare.” In the previous study, investigators determined that when the glare source was turned on, people started driving unsafely. “From their turns we could calculate the safety margin that they’re willing to accept to make the turn in front of the car,” Dr. Gray said. “The basic effect is that when the glare comes on they accept a smaller and smaller gap, so that they’re getting much closer to the oncoming vehicle.” Greater safety margin In the study, investigators found that this influenced the number of collisions. “There weren’t that many collisions in the simulator, but there were more under glare conditions,” Dr. Gray said. “What we think is happening is that glare through the reduction in contrast is interfering with people’s ability to process the motion of the approaching vehicle and judge how much time they have.” When comparing the blue light- filtering lens to the traditional IOL, investigators found a difference in the patient’s decision-making ability while driving. “Patients with the blue chromophore had a reduced effect of glare,” Dr. Gray said. “It still showed some effect but it was much less.” Investigators found that the safety margin for those with the blue light-filtering lens was significantly greater. For those in the blue light- filtering group there was about a 2.4-second improvement in timing. “In driving, this is quite a big difference,” Dr. Gray said. Overall, Dr. Gray sees the use