Question for People with Glasses

[BDawg]

I had to buy a pair of glasses to wear while I have an infection in my eye and cannot wear contacts.

I bought a pair of glasses from Lenscrafters on Friday with their "Featherweight" lenses. The problem I'm having is (espescially in bright light) I see a prism effect on edges when I look through the inside 1/4 or outside 1/3 of the lens. Is this normal? Has anyone else experienced this, and if so, could the optician fix it?

 

[mcveigh]

inside 1/4 outside 1/3 huh?

yes I notice it sometimes especially at night.

 

[Mnementh]

Ok I need a bit more information before I can answer this there's a few things it could be, first of all what is your prescription? What sort of lenses are they? When you say "featherweight" I assume you mean rimless (ie no frame around the lenses)? If they are rimless then the lenses should be made from polycarbonate which can cause the effects you are experiencing, however not all opticians are quite as concientious about the correct type of lenses so they might not be.

If you answwer those questions then I can narrow down the causes to one or two thing which your optician shuld be able to fix pretty easily.

 

[DingDingDao]

Originally posted by: BDawg
I bought a pair of glasses from Lenscrafters

That's your problem right there. Quality of product at Lenscrafters is on par with Yugo's efforts in the automobile industry. They make their eyeglasses using the cheapest possible components to sell glasses at the lowest possible price. You save money, but you get a crap product.

If you have vision coverage on your insurance, go to an opthamologist's office and get lenses from them. It'll be more expensive, but you'll get a much better lens that won't distort from center.

IMHO, there's no amount of money that is too much to spend on lenses--it's your eyes.

 

[MikePanic]

i get a prism effect also, but it's because i have rimless glasses - that is, the arms and nosepiece are drilled thru the glass rather then having a rim or wire around the glasses - im just used to it now

 

[Scarpozzi]

Originally posted by: DingDingDao

Originally posted by: BDawg
I bought a pair of glasses from Lenscrafters

That's your problem right there. Quality of product at Lenscrafters is on par with Yugo's efforts in the automobile industry. They make their eyeglasses using the cheapest possible components to sell glasses at the lowest possible price. You save money, but you get a crap product.

If you have vision coverage on your insurance, go to an opthamologist's office and get lenses from them. It'll be more expensive, but you'll get a much better lens that won't distort from center.

IMHO, there's no amount of money that is too much to spend on lenses--it's your eyes.

Good advice. Of course, I'm one that doesn't take a crap product lightly. If I'm not satisfied, I take whatever I paid for back and give them hell about it until they make it right. If their lenses are bad, they shouldn't be selling them in the first place.

 

[BDawg]

Originally posted by: Mnementh
Ok I need a bit more information before I can answer this there's a few things it could be, first of all what is your prescription? What sort of lenses are they? When you say "featherweight" I assume you mean rimless (ie no frame around the lenses)? If they are rimless then the lenses should be made from polycarbonate which can cause the effects you are experiencing, however not all opticians are quite as concientious about the correct type of lenses so they might not be.

If you answwer those questions then I can narrow down the causes to one or two thing which your optician shuld be able to fix pretty easily.

My prescription is something like -500 left / -550 right (I'm nearsighted). From what I read, the featherweights are polycarbonate lenses, but they're not rimless, there is a frame around the lenses.

Is there any way to tell more about the lens type?

 

[GtPrOjEcTX]

if you're used to contacts, I'd say give it 2-3 days and you'll probably get used to it.

 

[BDawg]

Originally posted by: DingDingDao

Originally posted by: BDawg
I bought a pair of glasses from Lenscrafters

That's your problem right there. Quality of product at Lenscrafters is on par with Yugo's efforts in the automobile industry. They make their eyeglasses using the cheapest possible components to sell glasses at the lowest possible price. You save money, but you get a crap product.

If you have vision coverage on your insurance, go to an opthamologist's office and get lenses from them. It'll be more expensive, but you'll get a much better lens that won't distort from center.

IMHO, there's no amount of money that is too much to spend on lenses--it's your eyes.

Yeah, I know, but I needed glasses that day. My opthamologist said I can't wear contacts for 2 weeks, and my spare glasses are so big and heavy that they hurt my face pretty bad. Cost wasn't an issue; speed was.

 

[BDawg]

Originally posted by: GtPrOjEcTX
if you're used to contacts, I'd say give it 2-3 days and you'll probably get used to it.

Today is day 4.

 

[TwoBills]

I'd take them back. Don't wait too long or you'll get the "your eyes have changed" routine. Glasses should give you crystal clear vision from all angles.

 

[GtPrOjEcTX]

Originally posted by: BDawg

Originally posted by: GtPrOjEcTX
if you're used to contacts, I'd say give it 2-3 days and you'll probably get used to it.

Today is day 4.

ok, well, then with my experience with wireframed featherweight lenses (what' I'm currently wearing and have been for many months), no I don't have that experience (-3.25,-3.50 perscription)

Got my at Dr. Bizers.

 

[Mnementh]

Originally posted by: BDawg

Originally posted by: Mnementh
Ok I need a bit more information before I can answer this there's a few things it could be, first of all what is your prescription? What sort of lenses are they? When you say "featherweight" I assume you mean rimless (ie no frame around the lenses)? If they are rimless then the lenses should be made from polycarbonate which can cause the effects you are experiencing, however not all opticians are quite as concientious about the correct type of lenses so they might not be.

If you answwer those questions then I can narrow down the causes to one or two thing which your optician shuld be able to fix pretty easily.

My prescription is something like -500 left / -550 right (I'm nearsighted). From what I read, the featherweights are polycarbonate lenses, but they're not rimless, there is a frame around the lenses.

Is there any way to tell more about the lens type?

There are ways of telling but you need to have experience and know what you're looking for. Your prescription is fairly high and the polycarbonate lens is a higher index material than normal plastic (which makes the lens slightly thinner and lighter). The problem you are experiencing is caused by a number of things, the most common being the fit/adjustment of the glasses, I won't go into the technical details as to why you are seeing the effect you are seeing suffice to say if the curve of the glasses around the front of your face is incorrect then you will see coloured edges around objects that get worse the further away from the centre of the lens you look.

This adjustment becomes more crucial the higher your prescription gets and the effect is made worse by higher index lenses

If adjusting the glasses makes no difference then you need to start looking at how the lenses have been made (and no it's got nothing to do with where the lenses are from before anybody jumps in bemoaning about buying cheap glasses), the lenses all come from 4 or 5 manufacturers and they are EXACTLY the same no matter which optician you get them from if they use the same manufacturer. The differences lie in how different manufacturers make the prescription, ie what curves they use to get the desired result. The thing your optician should be interested in if adjusting the fit does not help is whats called the Base Curve, if the base curve on your new lenses (it will be different because of the higher index material so you get flatter curves) is wildy different from your previous glasses it can cause some people problems, most people wouldn't notice but some people are very sensetive to changes.

As I said there's many things that can cause this problem I've mentioned the main ones however you should go see a qualified optician to get this resolved

 

[Mnementh]

Originally posted by: TwoBills
I'd take them back. Don't wait too long or you'll get the "your eyes have changed" routine. Glasses should give you crystal clear vision from all angles.

Not correct unfortunately, glasses only give you crystal clear vision through the centre of the lens, the vision gets progressively worse the further away from the centre you look, it also depends on the refractive index and the abbe number of the material the lenses are made from. With low to medium prescriptions the lessening of visual acuity is not noticeable to 99.9% of the population however with higher prescriptions it is very noticable.

 

[The Stigenator]

sounds normal - when you go from one format to another.

but just in case have it checked. When I went from Resilens to the new featherlite or magnalite lens, i found lense flares at night.. they disappeared in a few days.

The first time I drove at night it was so bad, i couldnt see jack because of lens flares, my friend had to navigate while i drove (he couldnt drive stick).

 

[richardycc]

sounds like you have high index lenses, and you are experiencing chromatic abberation. look for lenses with high abbe number, but they are expensive, like $300 and up.

 

[Mnementh]

Originally posted by: richardycc
sounds like you have high index lenses, and you are experiencing chromatic abberation. look for lenses with high abbe number, but they are expensive, like $300 and up.

The OP mentioned that he thinks the lenses are polycarbonate, which has a refractive index of 1.56 and a very low abbe number (can't remember exactly what off the top of my head it's been 5/6 years since I stopped practicing but it's in the high twenties, low thirties I believe maybe 31), tbh from what he's mentioned I would say it's down to frame adjustment, the frame just needs a bit more of a bow to it. Even with all the adjustments though polycarbonate will always suffer from chromatic abberation more than any other lens purely because of it's low abbe number, all you can do is try to minimise the effect till it's no longer noticeable by the wearer.

Hoya high index lenses have a fairly high abbe number and when you combine them with an MAR (multi anti reflective) coating they give very good results and are not that much more expensive than polycarb. If you are suffering from chromatic abberation with polycarb though then steer clear of Kodak Whitelights as they are almost as bad, unfortunately with lenses higher price doesn't always mean better (unless you're talking Zeiss heh)

 

[BDawg]

Well I went back and exchanged the lenses I had (they were polycarb) for a set of their high inded (1.67) plastic lenses. The prisiming is much less on these, but still present.

The optician there told me that about 2% of the population has trouble with polycarb lenses and the plastic ones should be better.

After reading the above replies from Mnemeth, I figured the problem may just be the positioning. I took my glasses off and angled them differently to give me a different lens angle...nothing.

I suppose I'm just wierd, but I never had this problem with my old thick dorky glasses nor with contacts.

 

[JimRaynor]

I have a prescription of -6.50 for contacts. My glasses for some reason are -7 or -7.50. Someone tell me why I can see fine with a tiny little contact but if I want to wear a pair of glasses they have to be coke bottles.

I was at lenscrafters and I was like ... "Eh, I dunno.... I mean my prescription is so high that the lenses are gonna be really thick."

Lenscrafter's guy: "No, we can make em pretty thin nowadays they won't be bad."

After I get the glasses: Coke bottles.

 

[Mnementh]

Originally posted by: JimRaynor
I have a prescription of -6.50 for contacts. My glasses for some reason are -7 or -7.50. Someone tell me why I can see fine with a tiny little contact but if I want to wear a pair of glasses they have to be coke bottles.

I was at lenscrafters and I was like ... "Eh, I dunno.... I mean my prescription is so high that the lenses are gonna be really thick."

Lenscrafter's guy: "No, we can make em pretty thin nowadays they won't be bad."

After I get the glasses: Coke bottles.

Contact lenses are very small so therefore are a lot thinner, they're also made out of a material with a different refractive index (can't remember exactly what) to the plastic your glasses are made from, they also don't have to be a certain thickness to start with for solidity and strength

 

[Mnementh]

Originally posted by: BDawg
Well I went back and exchanged the lenses I had (they were polycarb) for a set of their high inded (1.67) plastic lenses. The prisiming is much less on these, but still present.

The optician there told me that about 2% of the population has trouble with polycarb lenses and the plastic ones should be better.

After reading the above replies from Mnemeth, I figured the problem may just be the positioning. I took my glasses off and angled them differently to give me a different lens angle...nothing.

I suppose I'm just wierd, but I never had this problem with my old thick dorky glasses nor with contacts.

The 1.67 lenses will have a higher V (abbe number) than the polycarb so will automatically present less chromatic abberation, however they will have a lower V than standard CR-39 (standard plastic lenses) so will exhibit more abberations than that.

You might just be sensetive to the abberations some people are, I would still get the optician to adjust your glasses if they know what they are doing when you describe the symptoms they should start to bend the frame inwards at the bridge (nose), the only thing you can do if this doesn't solve the problem is have normal lenses or pick a frame with smaller lenses (the less distance from the centre of the lens the better), again your optician should be able to assist you in this, however this is where you let yourself down by going to cheap practices as they do not hire qualified staff as a rule.

Contacts won't exhibit the problem as they are in contact with your eye and move when they do so 99.9% of the time you are looking through the centre of the lens where the problem does not occur

 

[BDawg]

Update:

I called a couple of opthamologists' offices in town. I was told that this is a materials issue, not a craftsmanship issue. They use the same materials as everyone else, so they won't be able to offer me a different lens. I was told that some people are just more sensitive to the problems; I'm one of them.

 

[Mnementh]

Originally posted by: BDawg
Update:

I called a couple of opthamologists' offices in town. I was told that this is a materials issue, not a craftsmanship issue. They use the same materials as everyone else, so they won't be able to offer me a different lens. I was told that some people are just more sensitive to the problems; I'm one of them.

How can they say it's not a craftmanship issue without looking at them? It's not always a lens issue and in fact in most cases it's not. Opthalmologist btw won't know much about adjusting the fit of the glasses to eliminate these sorts of problems it's not their area of expertise, you need to speak to a Dispensing Optician (I think you just call them Opticians in the states) ie not the one who does the test but the one who actually dispenses the prescription and chooses the best lens type for you, as it is their area of expertise and they should be able to minimise the effect even if they can't eliminate it completely

 

[Kaieye]

You are noticing the mild chromatic abberation or fringing of the polycarbornate lens. Try to take it back and insist on 1.56 high index plastic lenses or 1.6. When you look thru or near the center of the lens - no problem. When you look thru the lens near the edge of these polycarb lenses , things are going to look slightly blurry.

But if it was me, I would just keep it until your eye infection subsides and never order polycarb again.

You can also try to put AR on the lenses but in my experience it does not help that much.

 

[BDawg]

Originally posted by: Kaieye
You are noticing the mild chromatic abberation or fringing of the polycarbornate lens. Try to take it back and insist on 1.56 high index plastic lenses or 1.6. When you look thru or near the center of the lens - no problem. When you look thru the lens near the edge of these polycarb lenses , things are going to look slightly blurry.

But if it was me, I would just keep it until your eye infection subsides and never order polycarb again.

The ones I'm in now are 1.67 plastic lenses.

I think I'll just suck it up and wait till the infection subsides. After that, I'll be looking into lasik.