Underwater eye adaption

[Narsil]

Moken Sea Gypsies - worth a glance:

http://www.cdnn.info/news/article/a040514.html

[wet]

Originally Posted by Narsil

Moken Sea Gypsies - worth a glance:

http://www.cdnn.info/news/article/a040514.html

Here is some more if interested, (some are slow-loading) with some pre-modern pics too.

Moken kids underwater
http://www.unesco.org/csi/act/thaila...en-Gislen2.htm
http://www.poyi.org/62/02/test_01.php

slideshows
http://www.mapraid.net/photomoken/pages/c-moken.htm
http://www.mapraid.net/ivanoff57/phot.htm

Natl Geographic slideshow:
http://www7.nationalgeographic.com/n...ine_extra.html
DDeden

[MBanks]

Wow, how much do I wish I was born and raised as one of them!?!?!

I'm now off to learn as much as I can about them!


M.

[MBanks]

infact, if anyone else as any more information on them I would love to be directed on it. I've obviously checked out online pages, haven't had a chance to search for any books or moving image documents of them yet though.

[naiad]

Very interesting. Once I was diving in the pool without goggles or mask, and it was a sunny day and the sun was shining into the pool. I found I could see much more clearly than normal underwater. It was definitely more than could be explained by the better light conditions, as things were in much better focus. It must have been due to constricted pupils caused by the bright light.

More here...
http://forums.deeperblue.net/showthread.php?t=50653
http://forums.deeperblue.net/showthread.php?t=64123

[wet]

Originally Posted by naiad

Very interesting. Once I was diving in the pool without goggles or mask, and it was a sunny day and the sun was shining into the pool. I found I could see much more clearly than normal underwater. It was definitely more than could be explained by the better light conditions, as things were in much better focus. It must have been due to constricted pupils caused by the bright light.

More here...
http://forums.deeperblue.net/showthread.php?t=50653
http://forums.deeperblue.net/showthread.php?t=64123

Re: Bright Sunshine + Shallow Water = Clear Vision

AFAIK, the only nocturnal (nighttime) feeding semi-aquatic or marine
mammals are a few dolphin species that feed on the fish schools which
feed on vertical night-time rising band of plankton. IOW, only those with
well-developed sonar echolocation generally feed at night, all the rest are
diurnal (daytime) feeders, there may be some exceptions.

"Under normal circumstances the pupil opens underwater to let in more
light. But the pupils of Moken children constrict under water... focal
depth is increased and resolution is improved. The Moken children also
accommodate maximally, that is, the muscles controlling the lens are
constricted and the lens changes shape, thus increasing the refraction
of light".

Seems to me that looking towards the general direction of the sun
while submerged would maintain pupil constriction, unless very deep.
If diver maintains that focus level while submerged by often looking
upwards (something that most divers don't do very often, since their
goal is to seek things below or at level with them); while using their
peripheral vision on objects beyond their preferred focus, then the
pupils would remain constricted.

Pupil constriction at depth was so counterintuitive to me, I couldn't
initially grasp the concept, but for habitual forage divers in sunny warm
clear marine waters it may be completely normal. It does likely seem
correlated to mid-day diving, not early morning or late evening when
the sky is darker, I'd think, and probably not in cooler deeper waters.
Just speculating, I don't know if this method is used by Moken. DDeden

Moken kids underwater pics, looking upwards
http://www.unesco.org/csi/act/thaila...en-Gislen2.htm
http://www.poyi.org/62/02/test_01.php