Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Tastes richer, less filling.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



Underwater contact lenses

Contact lenses designed to provide clear vision underwater
  [vote for,

Divers today have two choices - wear a bulky mask, or suffer from bleary vision underwater.

Most people think that blurry vision underwater is due to water irritating the eyes. This isn't the case. The lens of a human eye is simply calibrated to focus correctly at the specific index of refraction of the normal surrounding medium -- air. When submersed in water, the lens no longers refracts the light so that it correctly focuses on the retina.

Masks solve the problem by keeping a pocket of air around the lens, which then behave normally and can see through a flat plane of glass which doesn't distort the view. This pocket of air causes it's own problems though, as the mask pressure must contantly be adjusted as the diver's depth changes. This is why you can't dive with "swimming pool" goggles; there's no way to equalize the pressure, and your eyeballs get sucked out at depth as the air compresses!

This "error" in the focal length of the eye could be corrected with a specially designed contact lens, which will compensate for the index of refraction of water. Then, the wearer would be able to see clearly when the eye is directly in contact with water. (Of course, it would then be blurry in air...)

If losing the lenses due to the increased friction of water proved to be a problem, the diver could simply wear a small pair of "swimming pool" goggles -- which he would allow to fill with water -- to keep the water next the eyes still.

Tada! Clear vision under water, with no bulky vision-obscuring mask, and no air pressure problems.

TickleMeElmo, Sep 17 2001

Natural underwater vision http://groups.googl...wsbf02.news.aol.com
Man's account of vision so bad it didn't need these contacts! [TickleMeElmo, Sep 17 2001, last modified Oct 04 2004]


       A common misconception is that contact lenses would "float" out of your eyes if you opened them up underwater. Actually the reverse is true. The water pressure actually tends to "press" them onto the corneal surface much more effectively than air. If you remain perfectly still underwater, your lenses have almost no chance of slipping out of your eyes. Unfortunately, water has more mass than air, so splashing around in the surf, or diving into the water, or swimming into a strong current, might dislodge your contacts. The goggle idea would resolve this of course. So... +
eyeguy, Jan 27 2004

       As a diver with two prescription masks, one saltwater-soaked croissant for you.....
normzone, Jan 27 2004

       Good idea, but I like wearing my mask (I'm a certified diver) because it keeps water out of my nose. I'm giving you a croissant though because after adjusting, I'd probably love your contacts. When do you start making them?
theonecalledzil, Jan 27 2004

       Sounds like a great idea. I give it a +. Would this work as an off-the-shelf product for people with normal vision, or do contact lenses need to be more customized to the wearer? Would the lenses need to be different for different depths because of changes in water density? I imagine salt water and fresh water might require different lenses too.
BigBrother, Jan 28 2004

       If these became popular, I could also see another line of diving accessories: boat glasses which negate the effects of diving contacts so you can see clearly in air without removing the contacts. This would be handy for those relatively short times in between shallow dives.
BigBrother, Jan 28 2004

       this company has developed something similar http://www.fluidgoggles.com/indexf.html
shermster, Feb 11 2004


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle