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Read under water (was Cat's eyes)



Did somebody try to read small letters while under water?
It is probably impossible without a mask (or without
an additional positive lens), unless one is a sea lion. A very
nearsighted person may also be able to do this. Right?
Ludwik Kowalski

"Bernard G. Cleyet & Nancy Ann Seese" wrote:

People!

While everyone was on the subject of cats I forgot to mention some obvious fact about an aquatic mammal. The Calif. sea lion has a rather ingenious adaptation to sight for two very different
environments. We use our lens for focussing ~ 90% of the refraction occurring at the cornea, conversely the sea line has most of its refraction by the lens. It's rather large and spherical. So
what happens when it gets out of the water. With out the flat spot, ~ centered on its cornea, it would be grossly myopic. Cute no? A further refinement (a guess) is that since underwater not much
light, it probably has a rather sensitive retina. Above water it (day time) irises down, so most of the light enters through the flat spot.