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"High Index" eyeglass lenses - distortion?

Z

zixxer

Diamond Member
I've spent some time with google and was unable to provide a get a definitive answer -

My vision is 4.0 in one eye and 4.25 in the other. The optometrist at Costco really pushed their high index lens along with another option that makes the edges of the lens even thinner.. I asked if this affected peripheral vision and she insisted it did not, so I went ahead and got that as well.


However, after receiving the glasses it turns out that there is obvious distortion on the edges.. And I'm talking just barely off-center..



Opinions? Normally I would say 'buyer-beware' but the main reason I shop at Costco is that (in my experience) the employees never push anything that isn't really needed... I've always felt like I could walk in and trust what the employees have to say. I'm thinking about asking for a redo without this edge treatment but I'm not really sure if that's appropriate.


Opinions?

---Edit---

First off, I was wrong about my prescription.. My contacts are 4.00/3.75 and glasses are 3.75/3.50

Okay.. After talking to the 'optometrist' (possibly assistant, because she didn't really seem very confident in any of this stuff)

According to her, the problem is the edge polishing. Most people don't notice the distortion and color separation... That doesn't seem possible to me, especially the distortion. She recommends sticking with the 1.67 lens. However, they have these types:

CR39
1.59
1.67

She claims that my vision (in glasses- 3.75 and 3.50) is bad enough to make any other choice much too thick. I'm not really sure since my last pair of glasses were .25 less in each eye and didn't seem that thick - and they were the cheapest possible.. IIRC plastic not poly.

 
Your probably wearing Polycarbonate lenses which tends to have more chromatic aberration (fuzziness)as you look towards the outer edges of the lenses. This is some of the trade offs wearing "thinner" lenses. I noticed it when I wore Poly but it was not too big a thing for me.

If you ask for standard plastic or glass, this problem will probably go away but the old standard stuff will be thicker and heavier.

Your call...

 
All glass has distortion if you didn't know.

I have about 8 or 10 on my eyes so I went for thinner. It affected my peripheral vision but its so much better than wearing two blocks on my face.

My main downfall for peripheral vision is the small size of my frame and overall size of the lense
 
Well, to go into a bit more detail - If I'm looking straight ahead it's fine, and the 'inner' (closer to my nose) side of both lenses is fine.. it's the outer (near the hinge) section that gets blurry/fuzzy and slightly distorted (squished together)

So, when I look at something to the left, my right eye is clear while my left eye is 'blurry' and distorted.. It's pretty bad too, using dual monitor is giving me a migraine

 
Originally posted by: PlasmaBomb
You could try and consciously move your head rather than just moving your eyes when looking at things
Click to expand...

winner

i am bordering 10.0 and do not notice any distortion and have my lense as thin as possible
 
I assume your frames are new too? It might be that they are smaller than you are used to and that is the cause of the excessive distortion.

It might be worth it to get a pair of cheap 50's Clark Kent type glasses exclusively for use at your computer. Assuming that you're happy with the glasses except for the dual screen situation.
 
I had the same problem 7 or 8 years ago. And the optometrist (optician?) also pushed the high index polycarbonate lenses. I did some research back then and found plenty of places that noted that above a certain prescription, a lot of people found the polycarbonate lenses unsatisfactory for the exact reasons you're describing - blurriness due to the chromatic aberration.

I complained about them; they refused at the time to do anything about my complaint, insisting instead that I would "get used to them" and that within a week, I'd be happy with the trade-off of some distortion for the advantage of weight savings. (IMHO, it saves a couple grams. Not a big deal to me. I'm a big strong guy; I can handle an extra 10th of an ounce) Anyway, after a few days, I had realized that when shooting a rifle or a shotgun, there simply wasn't any way for me to see clearly - My head had to be turned and I would be looking through the peripheral area of the lens.

I did quite a bit of research - it took me quite a while to find articles from reputable sources - but I had enough when I returned to the store to imply that at the very least, they should have warned me that many people in the range where my prescription was found the lenses quite unsatisfactory. I also pointed out that when shooting a firearm (and I showed them how I stand and hold a shotgun), the lenses would be a huge factor in safety and that if there were any accidents, I wouldn't hesitate to point out to the courts that my optometrist said that the lenses were just fine and it was a matter of getting used to them. I almost think that was the turning point in getting them to relent and replace the lenses. FWIW, I've never been back to that optometrist again; and also fwiw, where I go now, they've never tried to push the polycarbonate lenses. Sorry, but I don't remember what my prescription is off the top of my head.
 
The optics doctor (damned if I know the name) told me that polycarbonate lenses weren't supposed to break, hence recommended for children (I got them at age 10 or so, and am only on my third pair in eight years).

I just looked chromatic abberration, and damn, now I see it in the corners of the lenses. It's pretty minor though if you get used to turning your head to look at things, I've never noticed it until now.
 
see:
chromatic aberration

And here
To minimize chromatic aberration, a doctor or wearer can:

Try to use the smallest vertical lens size that is comfortable. Generally, chromatic aberrations are more noticeable as the pupil moves vertically below the optical center of the lens (e.g., reading or looking at the ground while standing or walking). Keep in mind that a smaller vertical lens size will result in a greater amount of vertical head movement, especially while performing activities that involve short and intermediate distance viewing, which could lead to an increase in neck strain, especially in occupations involving a large vertical field of view.
Restrict the choice of lens material to the highest ABBE value at acceptable thickness. The oldest most basic commonly used lens materials also happen to have the best optical characteristics at the expense of corrective lens thickness (i.e., cosmetics). Newer materials have focused on improved cosmetics and increased impact safety, at the expense of optical quality. All lenses sold in USA pass the FDA ball-drop impact test,...
Click to expand...

And
Standard polycarbonate with an Abbe value of 30 is one of the worst materials optically, if chromatic aberration intolerance is of concern.
Click to expand...

While neither of those is a primary source, hopefully some of the sources listed in the wikipedia article will give you better luck.

 
Originally posted by: Kaieye
Your probably wearing Polycarbonate lenses which tends to have more chromatic aberration (fuzziness)as you look towards the outer edges of the lenses. This is some of the trade offs wearing "thinner" lenses. I noticed it when I wore Poly but it was not too big a thing for me.

If you ask for standard plastic or glass, this problem will probably go away but the old standard stuff will be thicker and heavier.

Your call...
Click to expand...

I've never had a problem with distortion or CA from polycarbonate lenses. Granted, my prescription is fairly mild, -1 and -2 sphere (right, then left) and -.75 cylinder (both eyes) so I'm not exactly pushing the envelope. I have noticed that every time I get a new prescription it takes me 2-5 days to acclimate myself to the changes though.

ZV
 
Originally posted by: DrPizza
I had the same problem 7 or 8 years ago. And the optometrist (optician?) also pushed the high index polycarbonate lenses. I did some research back then and found plenty of places that noted that above a certain prescription, a lot of people found the polycarbonate lenses unsatisfactory for the exact reasons you're describing - blurriness due to the chromatic aberration.

I complained about them; they refused at the time to do anything about my complaint, insisting instead that I would "get used to them" and that within a week, I'd be happy with the trade-off of some distortion for the advantage of weight savings. (IMHO, it saves a couple grams. Not a big deal to me. I'm a big strong guy; I can handle an extra 10th of an ounce) Anyway, after a few days, I had realized that when shooting a rifle or a shotgun, there simply wasn't any way for me to see clearly - My head had to be turned and I would be looking through the peripheral area of the lens.

I did quite a bit of research - it took me quite a while to find articles from reputable sources - but I had enough when I returned to the store to imply that at the very least, they should have warned me that many people in the range where my prescription was found the lenses quite unsatisfactory. I also pointed out that when shooting a firearm (and I showed them how I stand and hold a shotgun), the lenses would be a huge factor in safety and that if there were any accidents, I wouldn't hesitate to point out to the courts that my optometrist said that the lenses were just fine and it was a matter of getting used to them. I almost think that was the turning point in getting them to relent and replace the lenses. FWIW, I've never been back to that optometrist again; and also fwiw, where I go now, they've never tried to push the polycarbonate lenses. Sorry, but I don't remember what my prescription is off the top of my head.
Click to expand...

lol should have walked in with the guncase.
 
I think it varies from place to place. I ordered glasses with hi-index lenses from those Hong Kong retailers once and it was like looking through a fishbowl. I ended going to a Visionworks and even though I paid quite a bit more, there was very little perceptible distortion with their hi-index lenses (and I have horrible eyesight).
 
Originally posted by: CptObvious
I think it varies from place to place. I ordered glasses with hi-index lenses from those Hong Kong retailers once and it was like looking through a fishbowl. I ended going to a Visionworks and even though I paid quite a bit more, there was very little perceptible distortion with their hi-index lenses (and I have horrible eyesight).
Click to expand...

See this is where I'm wondering if the problem was with the edge polish like she said... She talked about how costco uses the highest grade lens brands and whatnot.

I can deal with a little bit of the color separation on the edge, but this much distortion is unacceptable - I ride a motorcycle and rely on having functional peripheral vision. I can deal with the lens size but the distortion is dangerous.


Also, these are just average sized frames.. They look similar to these:

http://us.st11.yimg.com/us.st....glasses_2000_282710240

 
I have been using high index glass not polycarbonate for quite some time. I had trouble with only one and it turned out that they messed up the grounding of the lens and hence the Inter ocular distance wasnt right They made me new lenses free of charge but I had severe headaches for the 2 days I wore them. My optician called them and told them of their mistake. Also lately I have been getting special coatings on my lenses that make them non-reflective and also give it better sharpness
 
Sounds like they cut the lenses incorrectly, resulting in excessive spherical aberration. Spherical aberration is caused by the geometry of the lens.
 
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