Viewing a single comment thread. View all comments

Ryan949 OP t1_j6h4e6u wrote

So if I understand you correctly, when suddenly going from a bright to dark environment or vice versa, the adjustment period is caused by our rods and cones adjusting the rate of photopigment production to return the photopigment to ideal operational quantities.

So when we go into a dark room, there aren't enough photopigments to catch what little light enters our eye and no signal gets sent to our brain and we're effectively blind until the photopigments get to high enough levels to detect the low light.

And in the reverse situation, there's too much photopigment so all our light cells are blaring/bleached and we're again blinded until the photopigment levels drop.

Is that right?


aggasalk t1_j6h5wm4 wrote

right except for the reverse situation. though it is a more-or-less passive process, the rod/cone pigments are constantly regenerating at the same rate regardless of light level.

when you go into a dark room, the cones are stocked with pigment but it's useless - but it will take a few minutes for the rods to be fully stocked, since they were bleached by your earlier exposure to light.

when you step from darkness to light, there is a brief flash since suddenly all your rods pigments are isomerizing, but the cones are functioning from the get-go.


aztronut t1_j6kbysc wrote

Full dark adaptation can take up to an hour but it varies with age and individual, typically 30-60 minutes.