The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 10-22-2012, 11:32 AM
Donnerwetter Donnerwetter is offline
Guest
 
Join Date: Apr 2012
Prescription windshields for driving a car?

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?
Reply With Quote
Advertisements  
  #2  
Old 10-22-2012, 11:37 AM
njtt njtt is offline
Guest
 
Join Date: Jul 2004
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.
Reply With Quote
  #3  
Old 10-22-2012, 11:41 AM
chargerrich chargerrich is offline
Guest
 
Join Date: Aug 2012
Talk about killing resale value

I can see KBB and NADA adding the "prescription windshield" option
Reply With Quote
  #4  
Old 10-22-2012, 11:54 AM
scr4 scr4 is offline
Guest
 
Join Date: Aug 1999
- 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.
Reply With Quote
  #5  
Old 10-22-2012, 12:27 PM
johnpost johnpost is offline
Guest
 
Join Date: Jul 2009
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.
Reply With Quote
  #6  
Old 10-22-2012, 12:48 PM
Seanette Seanette is offline
Guest
 
Join Date: Aug 2012
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.
Reply With Quote
  #7  
Old 10-22-2012, 12:56 PM
Donnerwetter Donnerwetter is offline
Guest
 
Join Date: Apr 2012
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).
Reply With Quote
  #8  
Old 10-22-2012, 12:59 PM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
How about just having 'reading windshields'?
Reply With Quote
  #9  
Old 10-22-2012, 01:29 PM
scr4 scr4 is offline
Guest
 
Join Date: Aug 1999
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.
Reply With Quote
  #10  
Old 10-22-2012, 01:57 PM
Telemark Telemark is offline
Charter Member
 
Join Date: Apr 2000
Location: Hub of the sports world
Posts: 15,381
Quote:
Originally Posted by Donnerwetter View Post
We'll have to assume that the owner of this car is an individual for whom money is absolutely no issue.
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.
Reply With Quote
  #11  
Old 10-22-2012, 01:59 PM
Gary T Gary T is offline
Member
 
Join Date: Mar 2002
Location: KCMO
Posts: 9,554
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.
Reply With Quote
  #12  
Old 10-22-2012, 02:08 PM
Donnerwetter Donnerwetter is offline
Guest
 
Join Date: Apr 2012
Of course, these prescription windshields would be high end progressive lenses.
Reply With Quote
  #13  
Old 10-22-2012, 02:15 PM
Doug K. Doug K. is offline
Guest
 
Join Date: Jul 1999
Quote:
Originally Posted by johnpost View Post
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.
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.
Reply With Quote
  #14  
Old 10-22-2012, 02:16 PM
Anaamika Anaamika is offline
Guest
 
Join Date: Nov 2001
Quote:
Originally Posted by scr4 View Post
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.
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.
Reply With Quote
  #15  
Old 10-22-2012, 02:32 PM
eschereal eschereal is offline
Guest
 
Join Date: Aug 2012
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.
Reply With Quote
  #16  
Old 10-22-2012, 04:52 PM
Zsofia Zsofia is offline
Guest
 
Join Date: Feb 2001
Quote:
Originally Posted by scr4 View Post
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.
I only need mine to drive at night (or a few other things in specific lighting conditions.) I had LASIK years ago.
Reply With Quote
  #17  
Old 10-22-2012, 05:01 PM
smithsb smithsb is offline
Member
 
Join Date: Sep 2002
Location: mid-Pacific
Posts: 1,488
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.
Reply With Quote
  #18  
Old 10-22-2012, 07:05 PM
engineer_comp_geek engineer_comp_geek is online now
Robot Mod in Beta Testing
Moderator
 
Join Date: Mar 2001
Location: Pennsylvania
Posts: 9,071
Quote:
Originally Posted by scr4 View Post
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.
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.
Reply With Quote
  #19  
Old 10-22-2012, 09:39 PM
kunilou kunilou is offline
Charter Member
 
Join Date: Apr 1999
Posts: 17,813
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.
Reply With Quote
  #20  
Old 10-22-2012, 09:40 PM
Leo Bloom Leo Bloom is offline
Keeping my password unchanged
 
Join Date: Jun 2009
Quote:
Originally Posted by smithsb View Post
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.
I think modern tanks use this when necessary.
Reply With Quote
  #21  
Old 10-22-2012, 09:43 PM
Seanette Seanette is offline
Guest
 
Join Date: Aug 2012
Quote:
Originally Posted by kunilou View Post
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 have the same problem (-8ish in each eye, at last exam).
Reply With Quote
  #22  
Old 10-22-2012, 10:00 PM
njtt njtt is offline
Guest
 
Join Date: Jul 2004
Quote:
Originally Posted by kunilou View Post
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.
You don't have to be able to focus where the lens is. You don't focus your eyes on the back surface of your glasses do you?
Reply With Quote
  #23  
Old 10-22-2012, 10:03 PM
Seanette Seanette is offline
Guest
 
Join Date: Aug 2012
Wouldn't there have to be a significant adjustment in correction to accommodate the user's eyes being two or three feet from the lens?
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 05:27 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright © 2013 Sun-Times Media, LLC.