A screen question.

"J. P. Gilliver (John)" wrote:

The original poster Peter Jason didn't say he only had [astigmatism]
in one eye.

Are your palm prints exactly the same for your right hand as for your
left hand? Nope. Same for your right and left fingerprints for the
matching fingers. Same for your eyes. Irregularities in the shape of
the cornea that generate refractive error (astigmatism) do not progress
equally in both eyes because the tissues are separate, not common. Many
folks with astigmatism have it in only one eye. While astigmatism
usually occurs concurrently in both eyes (bilateral), it is not
necessarily equal in both eyes (i.e., it can be asymmetrical).
Astigmatism in only one eye is often caused by injury (which is my case
due to a cat scratching my right eye when I was a kid) or by
degenerative eye conditions or disease; however, eyes do not degenerate
equally. No pair of disconnected tissue will degenerate equally.

Regardless of astigmatism, how often do eyeglass wearers get exactly the
same prescription for both eyes? Most users don't even know the specs
for their specs; that is, they go to the optometrist, get their exam,
and get their eyeglasses, and the bill they get never mentions the
sphere, cylinder, and axis measurements. If they want to keep their own
history of how their eyesight has degenerated, they have to ask for a
copy of the measurements to know what they are. Several times when I've
asked for the specs, they'd look mildly surpised and asked "Why do you
need to know?". I'd respond "Why shouldn't I know?"

In any case, for a monitor to correct vision impairment would mean the
screen would need to place a lens at your face to correct the refractive
error at the distance for where the pixels are painted. Don't know
about you, but having a large bubble of glass protrude from the monitor
against which I would have to press my face seems extreme compared to
putting on a pair of eyeglasses.

Remember the function of the lens is to correct your focus at a specific
distance. My eyeglasses for outside and driving would be impossible to
use for reading or the computer monitor, so I use prescription
eyeglasses for reading and computer. Likewise, my reading eyeglasses
would make everything slightly out of focus at distances. I did this
once when I went to a reunion and wore the wrong eyeglasses. They look
almost identical. I was wondering why my vision suddenly got so bad
beyond my arm's length. I don't like bifocals. I get a sore neck
tilting back my head to use the bottom lens portion for computer monitor
viewing.