of visual impairment, age, and cognitive status, as well as the complexity of the intersection—one-way, two-way, or roundabout. They are the first large-scale low vision studies that will be conducted in real-time, natural street-crossing environments. They are the first studies that allow subjects to respond in varying degrees of confidence, and not simply “Yes, I would cross,” or “No, I wouldn’t cross.” They are the first studies that will inform streetcrossing engineers to adopt design features that assist pedestrians in making safe crossing decisions. And they are the first studies that will investigate the effectiveness of an existing O&M street-crossing training program used by numerous O&M instructors across the country to teach elderly, visually impaired, and blind pedestrians safe street-crossing techniques. This study represents the first time ever that the training program will be assessed and measured. “This seemed like a very logical experiment to run,” says Dr. Hassan. “As a low vision optometrist, I’m going to see patients here in our optometry clinic that I’ll refer to an orientation and mobility specialist. I need to have confidence that when I’m referring a patient that there is a training program that’s been shown to work—one that helps the patient to increase their independence and quality of life.” Indicating confidence on a continuum addresses smaller components of the decision, Dr. Hassan says. And testing on real streets with real traffic (no study vehicle is employed in the experiment) will provide the first data with this level of authenticity. Similar past studies employed lab simulations or virtual reality programs, she says. “We are out in the real world, dealing with actual conditions.” GETTING TO THE OTHER SIDE On the other side of these studies, there will be quite a lot to celebrate. Optometrists, ophthalmologists, and other primary care providers will be able to more accurately identify patients who are at risk for making unsafe street-crossing decisions, based on a combination of factors. “I might find, for example, that being over the age of 80 with vision reduced to 20/70 puts a patient at twice the amount of risk compared to a person with 20/25 vision,” Dr. Hassan says. Assessing the effectiveness of an Orientation and Mobility streetcrossing training program for elderly and low-vision pedestrians will enable optometrists to refer patients to the program with confidence. “We’ll have more confidence of who to refer and what we’re referring them for,” she says. The studies will also inform roundabout intersection traffic engineers about design features that will enhance pedestrian safety, which Dr. Hassan says might include overhead bridges for pedestrians, rumble strips in the road that alert pedestrians about an approaching vehicle, or amber flashing lights that alert drivers to pedestrian crosswalks. But the most gratifying, significant application will be improving the lives of low vision patients. An optometrist at the very root, Dr. Hassan loves seeing her patients and interacting with them. Her clinical insights and her research are always informing each other, and her sessions with her low vision patients propel her to find ways to increase their independence. That’s why Dr. Hassan has devoted her research to the street-crossing studies. “It’s a way that I can make a difference in people’s lives,” she says. n UNDERSTANDING THE GAPS To better understand the difficulties low vision pedestrians meet at roundabout intersections, Dr. Hassan is beginning her street intersection complexity study with the least complex type of street-crossing: a one-way street. You’ll find Dr. Hassan and her team on Sare Road in Bloomington operating what she calls a “fancy laser trip-wire system,” which includes a laser beam pointer and sensors with computer chips that time-stamp the location of vehicles in relation to the pedestrian in real time, while sending that information directly to a laptop through wireless frequencies. This allows Dr. Hassan to gather truly real information about the pedestrian’s decision to cross in relation to the actual approaching vehicle—what she calls a gap discrimination task. For safety reasons, the pedestrian subjects cross the street only at the beginning of the experiment, accompanied by a member of the research team, when it’s safe to cross. After subjects are familiar with the crossing distance, they close their eyes at the crossing point while white noise is delivered to them through ear buds. At random times, the white noise stops, and subjects open their eyes to watch and listen to approaching vehicles for two seconds. At the end of the two-second period, subjects make a crossing decision, but they don’t cross the street—they press a clicker button, signifying how confident they would feel about crossing. The number of clicks indicates the level of confidence, on a scale of 1 to 5—1 click indicating the lowest confidence (definitely not enough time to cross), and 5 clicks indicating the most confidence (definitely enough time to cross). 7