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Old 03-28-2011, 03:05 PM
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Unhappy with new glasses -- what's different?

My old glasses are pretty beat up, so I recently went to an optometrist (a local chain) to get replacements. Well, I picked them up on Friday and I'm not happy with them at all. As soon as I put them on I could figure something was wrong -- somehow I couldn't see as well with them. With a bit of experimentation I think I've determined that I can see fine through the very center of the lens, but not well at all from any of the edges. And color fringing is much more apparent with the new glasses.

This is really noticeable at my desk, where I have lots of smallish-print text all over the walls. Before I could read anything without turning my head, but now I have to turn my head to a very precise angle to read much of anything.

So after twenty minutes on wikipedia extensive research, it seems that this is due to some combination of increased power error, chromatic aberration, or different lens geometry. But I'm not sure why my old glasses didn't have these problems to anywhere near this degree -- they should be pretty much the same, since my prescription hasn't changed (around -7, no astigmatism) and both old and new glasses have polycarbonate lenses in very similar frames. The only difference is that the new glasses have scratch-resistant and anti-reflective coatings.

Obviously I'd like to see as well as I could previously (minus all of the accumulated scratches in my old lenses). So I'm going to go back to the optometrist and see if they can give me better lenses. What should I ask for when I'm there?

Last edited by lazybratsche; 03-28-2011 at 03:06 PM.
Old 03-28-2011, 03:11 PM
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Don't assume it's just you. I had the same problem. They had screwed up the lens perscription and had mis-ground the lens.
Old 03-28-2011, 03:14 PM
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Quote:
Originally Posted by lazybratsche View Post
What should I ask for when I'm there?
To be able to see as well as you did before.

The OD is supposed to be the expert. Let him fix it.
Old 03-28-2011, 03:23 PM
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Quote:
Originally Posted by lazybratsche View Post
-- they should be pretty much the same, since my prescription hasn't changed (around -7, no astigmatism) and both old and new glasses have polycarbonate lenses in very similar frames. The only difference is that the new glasses have scratch-resistant and anti-reflective coatings.
The coatings wouldn't have the effect you described. You could check if the new lens (and the old) are aspherical, but I suspect both are (given the strong prescription).

How sure are you that the frames are similar? I recently bought a new pair of glasses with what I thought were similar frames, and had a very similar experience. The vision was perfectly fine through the middle of the lens, but there was strong distortion and aberration when looking off-center. We finally determined that the new frame placed the lens farther away from my eyes, and at a different angle (two lenses in nearly the same plane, rather than wrapping around my face). This was covered under warranty, so I was able to get a new pair with a different frame and that fixed the problem.

Last edited by scr4; 03-28-2011 at 03:24 PM.
Old 03-28-2011, 06:38 PM
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I have not in the last 10 years had a pair of glasses made where I didn't have to go back and have them redone. Go back and have them rechecked and remade.
Old 03-28-2011, 09:05 PM
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Polycarbonate is a common lens material that is notorious for high chromatic aberration, and at -7 diopters, your prescription is strong enough that you'd notice. If your old lenses were smaller in general, the chromatic aberration would be less noticeable. That's because chromatic aberration is generally more noticeable the farther you get from the center of the lens.

About the frames -- If your lenses are decentered in the frame to match the center of the lens up with up with the center of your pupils (which can happen if the frame is a particular size, generally larger than your inter-pupillary distance) then you are going to get more chromatic aberration when looking through one side of the lens. I know you mentioned the frames are similar to your old ones, but the size of the frames, and specifically the distance of each center of the lens-holding portion of the frame from the other, matters more than the shape of the frame.

You also didn't mention if you're wearing progressives (i.e. "no line bifocals."). Switching from one style of this type of lens to another can drive some people crazy. They're all a little different in terms of how much induced astigmatism they cause in the periphery of the lens, or how much "lens real-estate" you get for distance, intermediate and near vision. If you are wearing progressives, bring the old specs in so they can determine the brand and ask to be switched to the old brand / style of progressive.

That's all I can think of right now. Don't feel guilty at all about going back to the optometrist's office to ask for a re-make of the glasses (there is a reason we're trained in this stuff, after all!) Make sure you tell him or her exactly what you told us...that you can see out of the center but not the sides of the lens.

Last edited by cromulent; 03-28-2011 at 09:06 PM.
Old 03-28-2011, 09:33 PM
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I have the exact same problem; I figured that it was because I moved to progressives and so let it go. I've become pretty used to it now, but every once in a while I get annoyed when something in my periphery is not in focus.


mmm

Last edited by Mean Mr. Mustard; 03-28-2011 at 09:33 PM.
Old 03-28-2011, 09:38 PM
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Are you certain your old glasses are polycarbonate? I've been wearing glasses since i was 7, and have never been able to tolerate polycarbonate. I always go with CR-39 with its lower chromatic aberration. Glass is even better, but I can't find it in the US anymore, and that would be very heavy at your power unless the lenses were very small.
Old 03-28-2011, 09:45 PM
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Nope, not bifocals or progressive lenses or anything like that. Hopefully I won't need those for another twenty years at least...

The new frames have slightly wider and more square lenses, but otherwise are very similar to the old frames. The new lenses seem to be flatter than the old ones, though it's hard to tell given that I'm too blind to put them side by side and see the difference.

ETA: Old lenses are definitely polycarbonate. I've noticed chromatic aberration with them, but never this much. Now I see goddamn rainbows wherever there's something bright in my periphery.

Last edited by lazybratsche; 03-28-2011 at 09:47 PM.
Old 03-28-2011, 10:00 PM
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Can I ask, what should I ask about the eyestrain I get from working on the computer? I have progressives, and I have to enlarge the print to read most of the stuff on the computer, but the eyestrain is terrible. Can they make me glasses to deal with this or what?
Old 03-29-2011, 12:15 AM
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Read my old thread, I had a similar problem:

My new glasses are trying to kill me

Huh, I never posted the end of the story. Well, here it is. I told the doctor my problem. She had me look through some machine that measures refraction through your eye and spits out a pretty good approximation of needed prescription. With the glasses on she immediately saw some scattering that indicated defective lenses. Sent them back, got them replaced free of charge. Problem gone.

Last edited by GameHat; 03-29-2011 at 12:17 AM.
Old 03-29-2011, 09:59 AM
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Stopped by the optometrist this morning. The optician there adjusted the frames as a first step. It helps, especially with driving where detail vision isn't quite as critical, but it's not perfect. At least now I've got a slightly larger and better-aligned optical center, so I don't have to hunt as much for the the one bit that lets me see correctly. I'll see if I can adjust better over the next few days.

FTR I just measured my glasses. Old glasses have 50x29 mm ovalish lenses with a 20 mm bridge, new glasses have 54x29 mm squarish lenses with an 18 mm bridge.

Still there's an a lot more chromatic aberration and off-axis blurriness than I'm used to. Now I'm sitting at my desk at home, where I've got two 22" monitors at arms length. Again I can see fine through the optical center, but I have to constantly move my head to look at different parts of the screens. There's lots of color fringing, and high contrast bits wiggle when I move my head, especially when I look at test images like this.

So for lens materials... are all polycarbonates equivalent? If so I have to think the difference is due to differences in lens geometry or some defect. Now I'm considering paying the difference for hi-index or trivex lenses. (I think CR-39 would be unwieldy coke bottles in my prescription, even though it has better optical qualities.) How much less durable are hi-index lenses?

Last edited by lazybratsche; 03-29-2011 at 10:00 AM. Reason: typo
Old 03-29-2011, 03:42 PM
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I had this same problem when I last got a pair of new glasses. My previous glasses had been made of Spectralite (a material with low chromatic aberration). My new glasses were high-index 1.67, but I couldn't get used to them. Costco remade them and although they were better, I still couldn't tolerate the color fringing and off-axis blurriness.

I ended up having to go to a smaller optician (and pay quite a bit more) for Trivex lenses (Costco doesn't have a big selection of materials). I would have preferred to go with Spectralite again just because I knew that worked, but apparently it's hard to get nowadays (being an older material).

https://secure.wikimedia.org/wikiped...roperty_tables - look specifically for materials with a higher ABBE value on this table.

Last edited by acaos; 03-29-2011 at 03:44 PM.
Old 03-29-2011, 04:22 PM
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Had this problem more than once. What you should do is to bring the new and old pairs of glasses back to the optometrist. Since your main complaint about your old glasses was the scratches, tell him/her that you want a pair that is the same as the old pair but without the scratches! That's what I did once and that fixed it.
Old 04-26-2011, 12:26 PM
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Update: I went back and asked for hi-index lenses. Got them last week, and now I'm satisfied. I think my old lenses just had some sort of superior aspheric geometry -- as far as the optician could tell they were polycarbonate, but they had a much flatter base curve than the new polycarbonate lenses.
Old 04-26-2011, 01:20 PM
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All polycarbonate lenses are not the same. Several years ago I did work for a company that made polycarbonate lenses with superior optics compared to conventional polycarbonate. Their website is now quite dated but still informative (skip the flash intro).

resolutionlenses.com
Old 04-26-2011, 05:32 PM
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I just got new bifocals, and the optician explained that the refractive pattern is different between my old and new lenses. The old ones had a relatively straight dividing line between my reading and distance strengths -- the classic "look up for distance, look down for reading." The new ones progress more along an arc so I get a little more distance along the lower corners and a little more reading area in the center. Both prescriptions are the right strength, but it does take a little practice to retrain how I look at something.
Old 04-26-2011, 05:39 PM
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Is this a real optometrist/ophthalmologist, or one of those Lenscrafter joints? I had endless problems with Lenscrafters, and even after four trips back they never got the left eye correct. My new guy got it right on the first try.
Old 04-27-2011, 02:33 AM
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When my eyes deteriorated out of my first set of straight reading glasses I was talked into multifocals, so one pair would cope with reading, computer screens and distance (driving). Utter fail. The area of glass good for any given distance was so tiny I was continually ratcheting my head up and down to find the square millimetre that suited what I happened to be looking at. The ground was always wrong.

But the main problem was a computer screen was always rhomboidal; as I scanned my eyes from left to right on a line of text the screen warped to a degree that made me sick. When I quizzed them about it they admitted that the new glasses had large areas that were always going to look distorted, and assured me I'd get used to it. After two weeks I hadn't acclimatised one whit and made them exchange.

The downside is I now have 3 pairs; one for pure reading, one for computer (which have a sharply defined reading inset) and one for driving. Juggling them is a frikkin' nightmare but at least I don't get dizzy when I walk.

My point is that I suspect they've given you multifocals which have inbuilt areas of distortion, which would account for your reported symptoms.

Last edited by Askance; 04-27-2011 at 02:33 AM.
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