->> I know that a cat can adjust the incoming light in the eyes by open or
->> close the pupil.
->> The other day a used a flashlight right in the eyes of one of the cats and
->> normally I think that that would have blinded him but reacted at my
->> movement just beside the lamp.
->> Why wasn't he blinded?

 DW> Apaet from having strangely-shaped pupils, cats' eyes work pretty much as
 DW> our own.

 DW> If you had been in the cat's position, with a flashlight shining into your
 DW> eyes and someone moving near it, would you have seen the movement? I think
 DW> you would.

I didn't.

 DW> The light would have dazzled you a bit (not "blinded"), but not
 DW> enough to prevent you from seeing movement.

I was totally blinded and had to close them.

 DW> It's a bit like driving at night. The headlights of oncoming traffic can
 DW> be annoying, but they don't prevent you from seeing the road ahead.

Then you haven't been driving here. Everyone have at least 2 extra lights and
today they have those blue glass and/or xenon bulbs. Those are more than
annoying I can tell you.

 DW> Changing the size of the pupil is only one of the mechanisms by which eyes
 DW> adapt to varying light levels. The sensitivity of the retina changes, and
 DW> does so locally, so part of it can be more or less sensitive than the
 DW> rest. Shining a light into an eye makes the bit of the retina where the
 DW> light hits less sensitive, but other parts of the retina would remain
 DW> sensitive.

I had to close my eyes because of the light.

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