November 2019

NEWS

Research Highlights
AMD patients on the road: How visual acuity factors in


by Maxine Lipner EyeWorld Senior Contributing Writer

Just because a patient has been diagnosed with age-related macular degeneration (AMD) doesn’t mean they’ve given up driving. In a study published in Ophthalmology Retina,1 71.2% of patients were found to currently still get behind the wheel, according to Jennifer Patnaik, PhD. Of these patients, 12.4% were reported as having Snellen acuity of less than 20/40.
After routinely administering the National Eye Institute visual function questionnaire to patients, investigators noticed that when patients were asked about visual functionality with regular daily activities, scores surrounding driving were lowest for those with AMD. Given that driving can be a safety concern with normal acuity, investigators decided to examine how this was impacted by the condition, Dr. Patnaik said.

Considering driving issues

For this ongoing study, investigators drew from a registry of AMD patients seeking care at the Department of Ophthalmology of the University of Colorado School of Medicine beginning in 2014. “The registry also includes control data from patients who have cataracts but who don’t have AMD,” Dr. Patnaik said, adding that there are currently more than 1,000 patients enrolled in the study, including 553 with macular degeneration.
Study participants were asked to self-report how they felt about their driving when they were in different situations. Investigators were surprised about some of those who had given up driving. “Among patients who reported that they weren’t driving at all, almost half of them, 46%, met the Colorado state vision requirement and had visual acuity of 20/40 or better,” Dr. Patnaik said. Beyond vision, cognitive and physical functioning also play a role in patients determining whether they feel able to continue driving. Also, some elected not to drive in certain circumstances, such as at night, on highways, or in unfamiliar areas, Dr. Patnaik said.
Investigators found that among the 394 AMD patients who were still driving, those who had visual acuity that didn’t meet the state requirement of 20/40 or better experienced more difficulties, especially at night. Of those still driving, 87.6% had visual acuity of 20/40 or better, 9.6% had acuity of 20/50 to 20/60, and 2.8% had vision of less than this.

Weighing intervention

“When a patient comes in and they want to continue to drive and they can’t pass a standard state regulation test, they’re referred to our low-vision specialist to test additional visual function and determine whether they can drive or not,” Dr. Patnaik said.
In cases where an ophthalmic practitioner is concerned that a patient’s vision may present safety concerns for driving, they can advise a patient not to drive but can’t actually force them to give it up, she stressed. “Giving up driving can be difficult for patients; it’s giving up their independence,” Dr. Patnaik said. “So it might require a team approach involving practitioners and the patient’s family.”
Dr. Patnaik hopes the study elucidates for practitioners the problems that many macular degeneration patients can face while driving, even if the vision in their better eye does meet state standards. For those AMD patients whose vision is lower but who obtain permission to continue to drive, it can be even more problematic. “Driving with vision worse than 20/40 can be challenging,” she said. “Driving at night presents the greatest difficulty among patients who did not meet the state requirements, but we found that daytime driving was also difficult.”
Overall, Dr. Patnaik views the issue as continuing to grow in scope, with macular degeneration becoming more common. “The prevalence is increasing, as is older patients wanting to maintain their independence at some level and continue driving,” she said. “I think that it will become a bigger issue overall as we go forward.”

About the source

Jennifer Patnaik, PhD
Assistant professor
Department of Ophthalmology
University of Colorado School
of Medicine Aurora, Colorado

Reference

1. Patnaik JL, et al. Driving and visual acuity in patients with age-related macular degeneration. Ophthalmol Retina. 2019;3:336–342.

Relevant financial interests

Patnaik: None

Contact information

Patnaik
: Jennifer.Patnaik@cuanschutz.edu

AMD patients on the road: How visual acuity factors in AMD patients on the road: How visual acuity factors in
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