The drive for independence

The drive for independence

For people with losses in central visual acuity, bioptic telescopic spectacles may provide a way to maintain a driver's license—and the independence that comes with it.

"If your state offers bioptic training programs, look into them."

These devices are essentially like small telescopes implanted into regular spectacle lenses, says Bradley Dougherty, O.D., Ph.D., assistant professor at The Ohio State University College of Optometry. "Through training programs, patients learn how to dip their heads slightly to use these telescopes to spot distant road signs or other objects."

Many states allow some form of bioptic licensing, though standards and requirements vary greatly. As promising as these devices may be, Dr. Dougherty notes that little data exists related to how training and visual conditions predict performance on driving tests and, ultimately, road safety.

Assessing these unknowns is his goal. Dr. Dougherty and his research colleagues have unique access to a set of patients through the college's bioptic driving training program. The team's most recent work, "Vision, Training Hours, and Road Testing Results in Bioptic Drivers," published in the April 2015 issue of Optometry and Vision Science, looks specifically at the relation of training and previous experience to road testing results.

The team compared vision examination data and training program data with Highway Patrol testing results in 74 patients for which all three sets of information were available. The results came with one major surprise.

"So far, we're not able to use any visual factors to predict driver testing outcomes," Dr. Dougherty says.

"Person A, who has worse visual acuity than person B, does not have worse driving results. That surprised us, and we intend to work out the reasons in future research."

Less surprising, a bioptic driver's previous driving experience and hours spent training were indeed factors in testing success. A full 81 percent of people who had previous driving experience before entering the bioptic training program passed the Highway Patrol examination on their first try. These were people who, for example, may have been long-time licensed drivers but had stepped away from driving after being diagnosed with a visual condition.

In contrast, only 41 percent of candidates without previous driving experience before the training program passed the same exam on their first attempt. Among these patients, the largest representative group was people with albinism (45 percent).

"This is someone who, for instance, would have been told at a young age they could not drive and could not pass the test, but now the bioptic training gives them a chance," Dr. Dougherty notes. "Our results indicate they are likely to require more training time and attention to be successful and safe."

Dr. Dougherty cautions that this research is one step in a long process toward gauging road safety. Future papers will examine additional questions. Beyond simply predicting testing success, is previous experience more predictive of preventing actual crashes? And do certain visual conditions make crashes more likely?

For now, he offers a takeaway message for clinical practice: "If your state offers bioptic training programs, look into them. You may be able to give a variety of patients the chance to enter these programs."

June 24, 2015

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