Where does a physicist go to get a cow's eye? At his first stop - his neighbourhood grocery store in Cleveland, Ohio - NASA scientist and Guelph graduate Rafat Ansari struck out. "The people at the store looked at me as if I was from a different planet," he says, laughing at his recollection of scrounging materials for his early kitchen-counter experiments in detecting cataract development in the eye.

  What he did get from the bemused store clerk was the address of a Sandusky slaughterhouse. Returning eye in hand from the abbatoir, he faced another challenge. Although his PhD studies at U of G had given him a firm grounding in the physics of laser light scattering, they hadn't exactly prepared him for the niceties of dissection. Ansari enlisted the help of his daughter, Rahila - then in 10th grade - in removing the lens from the juvenile eye, then cooled it in an ice bath to induce a cataract.

  Then came the real test. Would his compact light-scattering probe - a miniature version of the device developed by his team at the U.S. National Aeronautics and Space Administration to study fluids in the microgravity environment of a space shuttle - be able to detect the cataract earlier than conventional techniques? Indeed it would. "Ansari's hunch had been right," said an article published in Microgravity News in 1996. "Just as the probe allowed new accuracy in observing the early stages of protein crystal growth, it could help scientists study the early stages of cataract formation."

  This fall, his work won him a NASA Public Service Medal, the highest honour paid to civilians by the space agency. He received the award at a ceremony at the NASA John Glenn Research Centre in Cleveland from astronaut Kathryn Sullivan.

  Ansari is now working with the National Institutes of Health (NIH) to adapt his probe for use in detecting and diagnosing eye diseases, and in screening drugs to halt or reverse the growth of cataracts. Early clinical trials have shown promise for early detection, he says. "Our technique is three to four orders of magnitude better than other methods," including one technique that measures the opacity of the lens only at a late stage of the disease.

  Under another agreement with the Food and Drug Administration, he is helping to adapt the probe to explore the effects of diabetes on the eyes. As with the cataract work, he hopes to provide a non-invasive tool for early detection and treatment.

  For Ansari, these projects incorporate a couple of personal angles. "I became the first volunteer patient," he says, describing his monthly visits to NIH to allow researchers to poke and prod at his eyes with the light-scattering probe. More important, he first entered the field about 10 years ago after his father developed cataracts. Quizzing doctor friends about the limited treatment options, he learned that cataracts were believed to be caused when protein crystals clumped in the lens. His response was to ask: "What about using a light-scattering probe to detect that agglomeration early?"

  His earlier work - including his PhD, completed at Guelph in 1985 - bore no connection to eye diseases or even to human health. After studying cryogenics and solid-state physics at the University of Karachi in his native Pakistan, he had come to Canada to complete his master's at the University of Calgary, where he learned of the research of U of G physics professor Ross Hallett. "Ross is one of the few pioneers in the area of laser light scattering in Canada - in fact, he is the pioneer," says Ansari of his former PhD supervisor.

  Hallett says he is "extremely proud" that NASA has recognized Ansari's contribution to applied research with its Public Service Medal. "I am also proud of the small part that I and the University of Guelph played in helping him develop his career."

  Hallett worked with Ansari on the use of light scattering in clarifying water used in coal processing. In the biomedical field, the U of G professor has used the technique to study proteins and sperm cell motility.

  Based on compact fibre optics, Ansari's dynamic light-scattering probe combines small size and low laser power to model cataracts and diabetic retinopathy in experiments on mice. Its low laser power requirement makes it safe for use on humans. Eye World, an international magazine for eye clinicians, recently selected the probe as one of four promising key ophthalmology technologies.

  Each year, about 50 million people around the world develop cataracts, five million of them in the United States. "Early diagnosis is really key," says Ansari. "In the year 2020, there will be a major crunch on the health-care system in the United States with the baby boomers aging. We already spend about $3.4 billion a year on cataract extraction surgeries."

  Because cataracts have been shown to be linked to ultraviolet radiation, they might eventually pose a problem for astronauts exposed to cosmic radiation, which is normally screened by Earth's atmosphere. "That is one area in which I'm working right now, to develop goggles or a helmet that an astronaut would wear," he says of his work at the National Centre for Microgravity Research on Fluids and Combustion at the Glenn Space Centre, where he is a principal researcher. He also teaches laser light scattering at Case Western Reserve University.

  And his father? "He got his cataracts removed in both eyes and he's doing fine," says Ansari. "He still wears glasses, but he can read and write."