You hear of folks (such as monks), who in the old days went blind or nearly so from excessive writing and reading by substandard light from candles, oil lamps, or whatever…
If this (poor lighting) is the actual cause of “eye strain,” what are the anatomical parts of the eye that get injured? The eye muscles?
Abe Lincoln was supposed to have done his lessons by the light from his fireplace in a dark dingy cabin. But I don’t remember seeing any pictures of him in aduthood wearing glasses.
People suffer vision problems from, computer monitors, but as far as I can tell, this is because of the particular kind of light that a CRT generates. Is this also called “eye strain”?
There are also the extraocular muscles that are the ones that make your eyes move up and down and left to right. Those can get pooped after awhile, I guess.
There are also the ciliary muscles for focussing. For things that are close-up, they contract and the lens becomes rounder. To see a distant object, the same muscles relax and the lens flattens. Kinda like when you see camera lenses getting longer or shorter depending on how the person is zooming and focussing. Your eye lens does a simlar thing. flattends thin or squooshes fat. There’s a diagram here that shows the itty bitty focussing muscles.
On me, it’s the ciliary muscles that used to get pooped and I’d wear glasses near the end of the day.
IMHO, it’s not the light levels that affect things as much. I know a lot of backstage technicians who read in the dark regularly with not a single problem. And on the other hand, I know a lot of architecture students and artist students whose eyeballs were moving and focussing and refocussing… ah, hell, we all needed glasses by the time we graduated!
Oh and BTW, with computers and other things that cause you to “stare” a lot, tend to have the effect of decreasing your blink rate.
So my eyes would get a bit more dried out and itchy, particularly during allergy season, contributing to the “tired eyes” feeling and a bit of a bloodshot look.
And thinking about my previous post. If it was really hard to see something, e.g. you were struggling to read in the dark, I suppose it would make the focussing muscles work more intensely and tired them out (possbibly damage them).