Re: Eyeglasses for Reading Sheet Music
Originally Posted by
Richard500
... Of course, more light helps out by giving you more depth of focus, so add a good bright lamp.
Originally Posted by
Louise NM
... With age, an excellent stand light is another necessity.
I'm often surprised at how many don't understand "why".
Our aging lenses have various types of distortion, much of it "distributed" around the lens somewhat randomly.
- In low light, the iris opens up to let in as much light (use as much of the lens) as possible, thus including all distorted areas in the field of vision. Great for seeing at all, not so great -for some of us- for seeing clearly.
- In bright light, the iris closes down to protect the eye, using only a small part of the available opening, and thus bypassing much of the lens' distortions. The benefit of bright light, often, is improved vision.
Two unrelated but on-point examples:
- For photographing very small objects (think models of trains, cars, landscapes, etc.) with a "life-size" perspective, some folks replace a camera's lens with a pinhole: a tiny hole in a small piece of metal. With a long enough exposure & small enough hole, a perfectly focused image is formed -without- using a lens at all.
- Some car enthusiasts have bemoaned the fact that fog lights automatically turn off when the high beams are turned on, thinking that "more light must be better". BUT fog lights are for close-in vision, while high beams are, obviously, for long range vision. If the fog lights remained on, brightening the close-in area, the pupil would close down (to at least some degree), thus limiting the light available for long-range vision, the purpose of high beams at all!
While these may seem like the opposite effect of brightening sheet music, they should help explain the eye's operative mechanics.
Sorry about the diversion...!
(No, I'm not a doctor, or even play one on television. My wife, on the otherhand ...)
Last edited by EdHanrahan; Feb-18-2022 at 10:44am.
Reason: disclaimer!
- Ed
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