AGING EYES BEHIND THE WHEEL; EXPERTS URGE STRICTER, MORE FREQUENT VISION TESTS FOR OLDER DRIVERS.

Byline: Michael Coit Staff Writer

This car-loving nation is getting older, and states should consider adopting more stringent eye tests and more frequent driving exams to keep unsafe drivers off the road, say eye doctors researching the controversial issue of senior drivers.

States including California have been wrangling with new standards to keep pace with aging motorists - one in four drivers will be over 65 in 2024 - and the trend was underscored Sunday by studies presented to a national eye research group meeting at Universal City through Wednesday.

Research to Prevent Blindness began its four-day meeting by presenting a special symposium with researchers giving their findings about the vision of older drivers, the impact of state policies on vision-testing older drivers, older drivers' quality of life with visual impairment, and related issues.

``We want to enhance the mobility of older adults, but we also want to do it to preserve safety,'' said Cynthia Owsley, a professor of ophthalmology at the University of Alabama-Birmingham.

Coincidentally, the conference follows a failed effort in the California Legislature to impose new testing requirements on older drivers.

Increasing concern about both the safety of older drivers and others on the road is helping drive researchers' studies.

For every 100,000 miles driven, the crash rate of older drivers is twice that of younger drivers, researchers say. Once involved in a crash, older adults are more likely to be disabled or die, according to studies.

``We're talking about people, we're talking about loved ones, and people are very concerned,'' said Melvin Shipp, a practicing aphthalmologist who also teaches at Alabama-Birmingham.

A study led by Gary Rubin, professor of ophthalmology at University College in London, found that older drivers make intelligent decisions about limiting or stopping driving. But the study also revealed that tests which states use to determine visual impairment don't measure enough and are not good predictors of involvement in crashes.

Rubin has been studying residents of Salisbury, Md., who are 65 and older to determine the prevalence of vision impairment and identify visual functions essential in daily life, such as reading newspapers, walking and driving.

About 5 percent of the study participants were visually impaired based on the standard used by most vehicle licensing bureaus to grant an unrestricted driver's license, including Maryland and California. That test measures visual acuity, which is an eye's ability to see fine detail.

Using other vision tests for a more comprehensive assessment, however, 10 percent to 15 percent were visually impaired. Those less common tests include measurements of an eye's ability to see darkness and lightness in objects, which is contrast sensitivity, visual fields, and sensitivity to glare.

Visual field loss and attention deficit turned out to be the most important predictors of crash involvement.

``The issue then is can we come up with screening tests to identify a driver that's a risk on the road,'' Rubin said.

He said more frequent road tests, in addition to more comprehensive eye tests, also are needed to gauge impacts of arthritis health affects. ``Only then can you find out if someone is a safe or unsafe driver.''

A San Francisco eye research institute found that visual acuity is relatively well preserved into old age. For many conditions encountered in the real world, however, dramatic vision losses were found.

The study by the Smith-Kettlewell institute showed a need to improve understanding of practical vision problems for both patients and doctors that aren't measured by the standard eye chart with black letters on a white background, said John Brabyn, the institute's senior scientist.

``It seems like much could be gained by testing more aspects of their vision, measurements that relate to real-world conditions,'' he said.

Surgery for cataract is another answer, according to the study by Owsley.

Cataract, which is cloudiness of an eye's crystalline lens, is the leading cause of vision loss among older adults.

Cataract is now largely reversible due to advanced surgical techniques.

The study followed crash rates of older adults who had the surgery and those who did not. The crash rate was 50 percent lower for those who elected the surgery, and they also reported less difficulty with more challenging driving maneuvers, Owsley said.