Everything I've ever read about dark adaption has mentioned that it's all about getting the largest pupil diameter possible, which only happens after the muscles fully relax after about half an hour of darkness.
I mentioned this to a friend of mine the other day who happens to be a professor of neuroscience, and he told me that was wrong, it's actually a bio
chemical process, not a bio
mechanical one.
A quick look on Wikipedia proved him right. I was stunned, stunned I say.
To condense / summarise
this page (Adaptation (eye));
"The human eye can function from very dark to very bright levels of light; its sensing capabilities reach across nine orders of magnitude.
[...] A
minor mechanism of adaptation is the pupillary light reflex, adjusting the amount of light that reaches the retina. [...] Changes in the sensitivity of rods and cones in the eye are
the major contributors to dark adaptation.
[...]Rhodopsin, a biological pigment in the photoreceptors of the retina immediately photobleaches in response to light. Rods are more sensitive to light and so take longer to fully adapt to the change in light. Rods, whose photopigments regenerate more slowly, do not reach their maximum sensitivity for about half an hour. Cones take approximately 9–10 minutes to adapt to the dark."
https://upload.wikimedia.org/wikiped...Adaptation.png
And from
this page on Accelerating Dark Adaptation in Humans;
"This adaptation period is different for both rod and cone cells and results from the regeneration of photopigments to restore retinal sensitivity.[1] Cone cells are able to regain maximum retinal sensitivity in 9–10 minutes of darkness whereas rods require 30–45 minutes to do so."
And according to that page, if you want to accelerate your dark adaption, make sure you're staying fit and getting enough Vitamin A and Anthocyanins.
Thinking about it, it's obvious. The pupil alone does not change diameter by nine orders of magnitude. There has to be something else at play here.
And of course, pupil size is still important for exit pupil calculations.
Anyway, I thought I'd put it up here in case anyone else was similarly misguided.
Markus