Do elderly people need to take their driving test again?

Obviously, you love your grandparents. They gave you money and/or treats when you were a kid and no matter what you did, they wouldn’t stop loving you. What you probably don’t see is their driving and if you have, you know you would want to be wearing two seat-belts and a helmet. They have a tendency to sight see and drift from lane to lane. You don’t want your grandparents to end up in the hospital or worse because their eyes have gone bad. Maybe petitioning and/or understanding that making them retake their drivers test again wouldn’t be so bad. This would help keep other drivers safe but your grandparents safe too. After all, no one wants to see their grandma be hurt.