NavList:

   

Reply

Bill Morris, you wrote:
"From a quick scan of the medical literature on solar retinopathy it seems 
that you can get retinal burns without using a telescope or gazing at the sun 
while under the influence of "substances". Several cases are reported of 
people simply sunbathing at low latitudes in bright sunlight."

Really? That's amazing! I would have thought that evolution would have 
eliminated this. That is, unaided vision should be relatively immune to 
damage from the Sun for "normal" people. Are we talking about fair-skinned 
northern Europeans lying on equatorial beaches? That's probably info not 
recorded in the abstracts in the medical papers... I've seen a couple of 
articles stating that repeated glimpses of the Sun over a course of some 
hours are associated with damage. I could imagine all-day sunbathers falling 
into that category. Maybe they even train themselves, unintentionally, to 
ignore the reflex to look away...

You wrote:
"I had assumed that the light intensity at the retina was greater, without really thinking about it."

And I certainly assumed as much until I saw the details worked out 
theoretically many years ago AND conducted some experiments to make sure it 
wasn't all "smoke and mirrors". It's certainly counter-intuitive, and there 
are plenty of specific cases of this that still confuse me.

-FER




--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply