Go Back   Physics Help Forum > Lobby > New Users

New Users New to PHF? Post up here and introduce yourself!

Like Tree1Likes
  • 1 Post By Woody
Reply
 
LinkBack Thread Tools Display Modes
Old Jan 8th 2017, 12:24 PM   #1
Junior Member
 
Join Date: Jan 2017
Posts: 4
Why doesn't light burns our eyes while we obsorb them

Where does the lights that we obsorbs into our eyes go??
Do they get sucked into our pupils?
If so our eyes should be burning because of the lights that we obsorb each day
the lights should transfer its energy into our eyes and causes our eyes to heat up and eventually burn?
Right??
Idk, just wondering lol
Stupid questions...
JustKiddingImNotAPhD is offline   Reply With Quote
Old Jan 9th 2017, 06:34 AM   #2
Forum Admin
 
topsquark's Avatar
 
Join Date: Apr 2008
Location: On the dance floor, baby!
Posts: 2,082
Originally Posted by JustKiddingImNotAPhD View Post
Where does the lights that we obsorbs into our eyes go??
Do they get sucked into our pupils?
If so our eyes should be burning because of the lights that we obsorb each day
the lights should transfer its energy into our eyes and causes our eyes to heat up and eventually burn?
Right??
Idk, just wondering lol
Stupid questions...
I'ts not a stupid question...at least I've never heard it asked before, so why should you not post it?

Anyway, the light coming into our eyes will not burn the retina for two reasons:
1) It's not energetic enough to burn at the levels it normally receives from ordinary sunlight (but be on the watch for lasers...even laser pointers have sufficient intensity to cause damage and you won't feel it as it's happening.)

2) Beyond whatever transfers the energy from the retina to the optic nerve the eye will respond to the light as a source of heat and the body will regulate that before any damage is done. (Again, watch out for lasers. They have too much intensity for the eye to easily regulate the heat.)

I've actually have had laser surgery on both eyes and I can verify that there is no pain despite the fact that the surgery was meant to burn out portions of my retina. On the other hand the intensity was well beyond the comfort range and I have no desire at all to repeat the experience.

-Dan
__________________
I'm a "something shiny" kind of...Oh look! Something shiny!

See the forum rules here.
topsquark is offline   Reply With Quote
Old Jan 10th 2017, 10:06 AM   #3
Senior Member
 
Woody's Avatar
 
Join Date: Jun 2016
Location: England
Posts: 158
The energy of the light drives chemical reactions in the retina,
which in turn drive electrical potentials along the optic nerve to the brain.
So the energy of the light is dissipated in the brain (as heat).
However the amount of heat generated by the light is actually tiny compared with the amount of heat generated by our normal metabolic functions.

However problems will arise if you look at high intensity light sources,
where the energy is delivered more quickly than it can be carried away.

At first you get spots before your eyes,
this is due to all the chemicals in the chemical reactions being used up.
Gradually this will clear as your eyes restore the proper chemical balance.

However if you persist in looking at the bright light, or the intensity is particularly high (e.g. the Sun, or a laser) then the cells in the eye can be permanently damaged.
topsquark likes this.
Woody is offline   Reply With Quote
Reply

  Physics Help Forum > Lobby > New Users

Tags
burns, eyes, light, obsorb



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
seems that mathtype doesn't parse a simple amsmath code sepinaz LateX Help 1 Aug 10th 2015 02:09 PM
Can light travel faster than the speed of light? kiwiheretic Light and Optics 4 Apr 2nd 2014 10:52 AM
Eyes werehk General Physics 1 Jul 4th 2008 03:31 AM


Facebook Twitter Google+ RSS Feed