Re: Ultra Dark-Adaptation?


Who knows. I agree with the majority of the posters here -
it was likely a night of exceptional transparency.

However it's certainly possible you may have temporarily
increased the sensitivity of the old rod cells. My half baked
theory would posit that exposure to UV radiation (rod cells are
quite sensitive to UV down to at least 380 nm - whether your
cornea is transparent to this radiation is another question) may
have damaged them just a little bit. Enough that they recovered
and overcompensated their rhodopsin production, sort of like what
happens when you exercise to increase muscle strength. However
it's well known that exposure to too much light bleaches them of
rhodopsin and blunts dark adaption, sometimes for days after the
exposure.

Rod cells are interesting things. They've got these stacks of
membranes loaded with rhodopsin which is being constantly
recycled. I can't remember where I saw it, but there was this
amazing electron microscope image of rhodopsin molecules
in a rod cell, and it looked cystalline, like every bit of space in
the membrane was packed with it. I found it amazing that these
cells can constantly recycle the stuff and maintain the integrity
of the membrane for as long as they do. No wonder dark adaption
can take some time.

As far as diet, I wish I new of something you could eat to boost
sensitivity. It used to be thought blueberries might help, but
apparently no tests have backed this up. One thing that DOES
help, at least a little, are black currants. Apparently they must
be imported from Europe, but many grocery stores carry a
black currant juice imported from Belgium ('Looza'). It's a very dark
purple in color, tart & tasty. Kinda expensive though. I drink about
a liter of it a week. Anyway, I believe they tested people with it and
found a very modest increase in contrast detection threshold in the
dark adapted eye - no more than 5% I believe. Whether or not this
is significant I don't know

Eric

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