Just got glasses for the first time, pretty weak prescription, -0.5 either eye, mostly due to headaches while using a computer. Went and ordered some with single vision intermediate lenses, and I’m wondering if it’s possible to wear these glasses all the time, not only while looking at stuff from an intermediate distance (i.e. a computer). Is this in any way damaging? My distance vision is sharpened while wearing them; no part of my vision seems more blurry with them on. Would really appreciate it if anyone could weigh in on this.
You don’t say how old you are, but if you’ve just begun having problems with a computer monitor (presumably at about arm’s-length) it sounds like your presbyopia is just starting to be a problem. It may take a few years, but you’ll eventually notice that your intermediate vision differs enough from both near and distant vision that a single correction won’t work anymore.
Well, I’m only 22; isn’t presbyopia an age thing? And does that mean that for the time being - while the distance/intermediate are similar and everything seems better - it’s ok eye-safety-wise to go with an intermediate lens?
What, exactly, are you afraid will happen?
Looking through lenses won’t hurt your eyes. If they don’t correct your vision properly they might give you eyestrain, but it sounds like you might have less eyestrain with them than without.
You have a mild prescription. However, wearing that prescription all the time will no more “hurt” or “damage” your eyes than my wearing of my high-power prescription all the time would. (Actually, as I’ve aged into presbyopia territory my near-sightedness has lessened, not increased, meaning I’m inching towards normal. I should be 20/20 by the time I’m 1,253 or so…)
I’m guessing an eye professional will say while you need not wear your lenses at all times (needing them mainly for computer work) there is no harm in doing so. It’s a matter of comfort. If you’re more comfortable with than without then wear them.
If you are really concerned see an eye doctor. But if they are prescription lenses I assume you have already seen one.
Yeah, I’ve seen an eye doctor. She advised me to wear them for arms-length stuff, but also that it’d be fine to wear them whenever. Only problem is, nothing about intermediate lenses were mentioned. This is the crux of it really: I’m completely ignorant about this kind of thing, but the term ‘intermediate’ is making me think it’s improper to use them for non-intermediate purposes. So that’s all it boils down to, really. A sort of superstition about the word ‘intermediate’. Looks like I’m just being an idiot. Thanks for the help 
The “intermediate” just means they’re optimized for that distance range. You still being in your 20’s, your eyes probably have sufficient focusing power to compensate for times when the lenses are less optimal. If you wore them while, for example, exclusively focusing in the far distance you might experience fatigue faster with them than without but if you live most of your life focusing at intermediate distances then wearing them most of the time won’t be a problem.
We you get to be an old fart like me your eyes don’t change focus so well, so now I have two prescriptions i.e. “bifocals” (actually, progressives) so I can switch between “distance optimized” and “near optimized” without having to change my glasses, but I wear 'em all the time so no big deal. I just look through the part of the lens that is most comfortable for viewing what I’m looking at, but if I use the “wrong” part of the lens no harm done, either my eyes have to work a little harder, or the image is slightly blurry.
Your ability to change focus to other ranges while wearing intermediate range lenses is actually a sign of young, healthy eyes. Enjoy them while that’s the case.
And when you get to be an even older fart like me, you get to have three prescriptions, i.e., “trifocals.” Lots of fun.
I have a similar prescription to you.
Do you have trouble reading fine print like on pill bottles when wearing your glasses? (it’s harder to read with the glasses on then off) If you do, you might have the problem I have.
Accommodative insufficiency.
Basically, because we didn’t get glasses until later in life, our eye muscles didn’t learn to focus well for near reading when we have glasses on. If this is a problem with you when you wear glasses, then the therapy for it is to do exercises for your eye muscles.
To the OP, are you near-sighted or far-sighted? I am near-sighted; my corrective prescription (sphere) is a negative number.
Drugstore reading glasses to correct farsightedness are usually start out at +1.
My guess is intermediate glasses would be something like a +0.3?
If his prescription is for -.5, and he tries to wear +0.3, won’t that make his vision worse?
Any experts out there? Is this a plus cylinder versus minus cylinder thing?
No, as has been explained, the “intermediate” refers to the distance for which the glasses are optimized. +0.3 is not “intermediate”, it’s just “very low”, as is -0.3
Wearing glasses that are off by .8 would make his vision worse but not overtime: instantly. It would be worse than not having his glasses on (BTDT, for a year and with only the left eye glass: I had to close that eye to look into the distance, since my parents refused to believe the glasses were wrong). He’s not going to do it, specially since we know he notices differences of .5 and he’s 22, not 11.
For reading glasses, the sphere is typically +1 to +2.
What sphere would be considered intermediate?
That’s what I meant; If he puts on a pair of glasses with an absolute sphere of +.3, his vision will immediately get worse. It is unclear to me if the intermediate glasses he ordered are prescription, or if he ordered some glasses labeled intermediate which mean intermediate for a person with normal vision.
Night, so be it, are these intermediate glasses which you ordered prescription glasses, or just glasses you found on the internet that are labeled intermediate?
Nope, pretty much everything is clearer, although close-up the difference is very, very slight.
I’m near-sighted, I think. Prescriptions with a minus symbols are near-sighted, those with plus are far-sighted (again, I think).
They’re prescription glasses. Single vision intermediate lenses to the prescription given by my optician.
That is correct. The technical terms are myopia (near-sighted) and hyperopia (far-sighted), but the term “presbyopia” which refers to the worsening of accomodation caused by aging is sometimes used for far-sighted, too.
Either there’s some information missing, or something’s not quite right. In the OP you say the prescription is just -0.50 in both eyes, but there’s no way to make intermediate lenses from that. It requires a bifocal prescription. An intermediate prescription is figured by adding half the add power to the distance correction. For example, -0.50 in both eyes with a 1.50 add would yield -0.50 + .75 for an intermediate power of +0.25. It’s the power that would be in the middle part of a trifocal.
Hmmm, that’s interesting. Perhaps that’s why the lenses feel like they could be all-purpose (i.e. distance), rather than anything specific. The only missing information is how they were purchased: all I did was look online for frames + lenses, entered my prescription (same for both eyes: SPH infinity, CYL -0.50, AXIS 180 - this is all the information I entered, by the way), picked ‘intermediate lenses’ as they were mainly for computer use, and that’s it. Now I’m even more confused.
You have a mild astigmatism correction. It’s the first number that determines whether you’re near-sighted or far-sighted. Infinity means the same as plano, or 0.00. You’ll see better with them at any distance. I suspect the doctor meant that if you don’t want to wear them all the time to just wear them for computer work. If you get in the habit of wearing them all the time you’ll reduce the chance of losing or forgetting them. On the other hand, if you keep them on your desk and only use them when working on the computer, you don’t have to worry so much about bumping them or knocking them off.
Thanks a lot, very helpful indeed. So, really, my having ‘intermediate single vision lenses’ in this case means nothing? Regardless of what type of single vision lense, with that prescription it’ll improve vision at any depth?