“Can I drive?” Help patients answer the question

“Can I drive?” Help patients answer the question

It's an optometrist's responsibility to tell patients when they no longer meet the vision requirements to drive.

Once the OD provides and helps interpret the results, "it's up to the patient and the family to decide how to use that information."

According to Paul Freeman, O.D., a private practitioner in Pennsylvania and a diplomate in low vision with the American Academy of Optometry, a number of visual processing components factor into safe driving. For example, state driving laws use visual acuity and visual fields as cutoffs for different driving privileges.

Determining whether a patient is legally fit to drive involves a number of steps.

1. Assess why vision is declining.

Determine whether the cause is natural or disease related, and what interventions might be able to slow down, stop or reverse these changes.

2. Discuss vision changes with the patient.
Talking about vision changes as they relate to activities of daily living, including driving, is essential to helping the patient understand their potential impact. "Patients should know their legal driving status as it relates to specific visual findings," Dr. Freeman says.

3. Perform tests.
Dr. Freeman says he uses a battery of tests to determine if the patient is able to continue to drive:

  • A standard visual acuity chart, which measures the ability to see targets of decreasing size while keeping the contrast of the target the same, usually with maximum contrast.

  • Contrast sensitivity testing, which maintains a target at a specific size, but varies the contrast. Such a test assesses the full visual range of potential targets seen in the environment.

  • Glare sensitivity response is another test that's specifically related to the physiology of the eye-and to driving.

  • Functional tests to determine a person's visual awareness and ability to process information in a specific visual area without eye or head movement. One test, the Useful Field of View, evaluates response time and accuracy of visual processing, divided attention and selective attention.

Once the OD provides and helps interpret the results, "it's up to the patient and the family to decide how to use that information," Dr. Freeman says.

Learn more about how ODs help patients make a critical decision on page 22 of the January/February 2015 issue of AOA Focus.

January 29, 2015

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