I was listening to a skit by comedian Brian Regan. He was cracking a joke about a guy who wears glasses only when he drives. Regan asks him: “So why don’t you use prescription windshields?”.
Come to think of it, why not? Why not have individually manufactured windshields in your car to correct your vision while driving?
Only one person would be able to drive the car.
If you moved your head very much, everything would go out of focus.
Huge lenses are expensive to make.
Talk about killing resale value 
I can see KBB and NADA adding the “prescription windshield” option :smack:
It would cause horrible distortion. Eyeglasses have distortion too, but mainly in the peripheral vision; there’s no distortion in the direction you are facing. With a prescription windshield, you’ll ALWAYS have distortion in certain directions.
It would be incredibly expensive to grind and polish such a large lens. It could be molded plastic, but plastic scratches easily.
A lens that big would be very thick at the edge.
Most people who wear eyeglasses need different prescription for each eye. A prescription windshield will have a single fixed prescription.
it would require a head clamp in the headrest to keep the eye to lens distance constant for focusing. hairstyles would need to be developed with clamping areas.
seat adjustments would also have to be disabled.
this would restrict each car to a single driver. this might be of some advantage to parents; if you can’t afford an additional car then the kids don’t drive.
Aside from the problem that only one person could drive the car, most people who need vision correction do find that the needed correction changes with time. I’d rather not have to change my windshield every two or three years.
We’ll have to assume that the owner of this car is an individual for whom money is absolutely no issue. This Mercedes with prescription windshields will be his Mercedes No. 78 (think Arab sheik).
How about just having ‘reading windshields’?
By the way, are there really people who only wear glasses when they drive? I think if your eyes aren’t good enough for driving, they aren’t good enough for most outdoor activities.
Doesn’t really matter, since the driver’s head doesn’t stay in exactly the same position while driving. If you can figure out how to drive without moving your head at all then it could be possible.
When driving it’s sometimes necessary to see out of the other windows, thus all of the concerns over the windshield multiplied by 4, 6, or 8.
Of course, these prescription windshields would be high end progressive lenses.
That still wouldn’t work. The windshield would have to wrap around the driver’s head so that every spot on the windshield was the same distance from the driver’s eyes. Also, edge thickness goes up exponentially the larger the lens is. The edge thickness of a lens the size of a windshield would be measured in feet, even if you could get a 1.5mm center thickness.
Yes there really are. better are the people who need glasses for driving and still refuse to wear them. I’m not sure why still so much hate against glasses.
A hologram recreates the properties of what it records. A white-light hologram is created using a diffraction slit so that it can be viewed without the reference beam (laser) used to create it. Hence, one could in theory create a working hologram of a prescription lens, complete with astigmatism cylinder, applied to a film you could attach to the front and side windows and mirror (which could be removed for other drivers).
The downside is that white light holograms (like the bird on your VISA card) kind of lack color stability, so there would be some odd distortion effects. In addition, the driver’s eyes would need to be very similar in correction: it would not work for someone like me whose correction between the eyes differs by a factor of nearly 3.
I only need mine to drive at night (or a few other things in specific lighting conditions.) I had LASIK years ago.
I’m thinking no windshields or windows in the car. Just panoramic cameras all around hooked up to a virtual reality helmet. Could be individually tuned to the persons eyesight. Tough on passengers though.
And when he/she gets really old, the family could just feed in trips with video, sound, and motion actuators so the old coot wouldn’t actually be on the road.
I am one of those people. I only wear my glasses when I drive, and even then only at night or when I am tired. I can easily see well enough to judge where I am and where other cars are without my glasses on. What I can’t do is read street signs. With the reduced visibility at night things get a bit blurry too. I can probably see well enough to drive even without my glasses but I feel more comfortable with them on.
I don’t know what outdoor activities you think I need to wear glasses for. I can’t recognize faces at a distance but that’s never been much of an issue. I can easily see where I’m going if I’m out hiking or doing pretty much anything else outside.
The only other place I really notice my vision problems is when watching TV. With a reasonably sized TV that’s not an issue. HD doesn’t mean much to me because I can just barely see the difference with it.
Since turning 40 I also need reading glasses. I don’t like to wear glasses normally, so I also only wear those when I need them. I keep a pair at home in my desk and at work on my desk. I can go most of the day without using them usually, but I definitely need them on occasion.
I don’t know what kind of prescription anyone else is talking about, but my eyes are so bad I can’t see a thing at windshield distance. I’d have to have correction just so I could focus on the correction.
I think modern tanks use this when necessary.