# A LOT of bright light - damage to eyes? **URL:** \ **Category:** Factual Questions\ **Created:** [August 9, 2006, 6:58pm UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040 "2006-08-09T18:58:03Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Placid\_Liver](https://avatars.discourse-cdn.com/v4/letter/p/e99b99/32.png) [@Placid\_Liver](https://boards.straightdope.com/u/Placid_Liver)\ **Post date:** [August 9, 2006, 6:58pm UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/1 "2006-08-09T18:58:03Z")
The other day I had to help do some work on a roof for a few hours on a very hot bright day. The roof was white, and when I eventually came down, what I’d thought was bright on the ground seemed rather dim and when I went indoors I was near-blind for a few minutes - after which all was fine again. Can this sort of light do permanent damage to the retinas? How much exposure would be necessary? (don’t know if it’s worth noting I have that sort of condition that causes people to sneeze sometimes when exposed to bright sunlight. At least, I heard some other people have this, maybe I’m just a freak.) ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [August 9, 2006, 7:02pm UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/2 "2006-08-09T19:02:41Z")
It’s possible you might garner yourself a case of eye irritation similar to “snowblindness” as a result of your work. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [August 9, 2006, 9:20pm UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/3 "2006-08-09T21:20:19Z")
I doubt one day’s worth of that sort of exposure would do any lasting damage, but it can be pretty painful. I once did a day’s skiing in bright sunlight with no eye protection, as I’d left my goggles behind and was too lazy to go back to the hotel and get them. It didn’t seem so bad at the time but my eyes were really sore for about 24 hours afterwards. On the whole I think a lot of scaremongering goes on about sunlight and eyes, though. They’re pretty hardy, although UV exposure can be a factor in developing cataracts later in life. ---
**Author:** ![ryobserver](https://avatars.discourse-cdn.com/v4/letter/r/b2d939/32.png) [@ryobserver](https://boards.straightdope.com/u/ryobserver)\ **Post date:** [August 9, 2006, 10:51pm UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/4 "2006-08-09T22:51:30Z")
Snow blindess (or glare blindness, or photokeratitis to be technical) is a sort of sunburn of the cornea. Like sunburn of the skin, it may not become obvious until several hours after exposure, when it’s too late to do anything except suffer and hope it clears up quickly. Working on a white roof may not damage your eyes permanently, but why take a chance? These are your EYES for heaven’s sake. If in doubt, get sunglasses. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [August 10, 2006, 1:19am UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/5 "2006-08-10T01:19:49Z")
I understand (from advice given by Richard Feynman) that bright light in the visible band won’t hurt your eyes, but you are getting reflections of just about the whole spectrum of what comes down, including IR and UV. Get a pair of good UV-filtering shades. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [August 10, 2006, 1:23am UTC](https://boards.straightdope.com/t/a-lot-of-bright-light-damage-to-eyes/368040/6 "2006-08-10T01:23:26Z")
> [@Placid Liver](#): > > . . .I was near-blind for a few minutes. . . . I have that sort of condition that causes people to sneeze sometimes when exposed to bright sunlight. At least, I heard some other people have this, maybe I’m just a freak.) Should add that your experience was normal, the retinal cells take up to 30 minutes to fully adjust to a dramatic change from bright light to dim light. Also, Cecil sez lots of people have the [sneezing thing](http://www.straightdope.com/classics/a2_303.html), it’s some kind of crosstalk in the nerves.