BOSTON -- Many people are afraid they won't be able to drive as they get older because that means losing their independence. So they worry about their vision.

NewsCenter 5's Heather Unruh said that local researcher, Dr. Eli Peli, wrote "Driving With Confidence" to help people with impaired vision stay on the road.

Arline Austin, 68, is in the driver's seat, thanks to a bioptic telescope mounted on her glasses.

"This left lens enables you to see the traffic lights, and it enables you to see oncoming traffic," Austin said.

Macular degeneration long ago left streets signs a total blur for Austin. But the special specs focus one eye so sharply that she's legally licensed to drive in Massachusetts.

Experts say there are people who clearly should not be allowed to drive, but how do you know if you're one of them?

Peli's book says to look for three clear signs.

First is side-vision loss. With driving, it's a dangerous combination.

"If you drive and you're planning on moving to another lane and somebody's overtaking you and you don't see them," Peli explained about the danger.

It's often so gradual that drivers don't notice the change.

"Many people with that kind of loss may be driving. In fact, we know they're driving from some studies that have looked into this," Peli said.

Another problem is one that an eye exam can easily spot. You can't miss loss of sharpness. It's no secret that driving requires reading.

"We use road signs, and you need sharp vision to see traffic signs," Peli said.

For Austin, magnification clearly helps, and with doctor certification, it can work for others.

Peli said that there's no fixing loss of confidence.

"If they have any doubt about the safety of their driving they should get off the road," Peli said.

Austin said that if she becomes a threat to anyone, she'll put the brakes on her driving without being told.