Trouble with New Trivex Lenses

[mshimp]

Try this! Take a low power poly or trivex lens(like a -2.00) and cut it to perfect size in a full rim frame on one side.On the other side do the same except leave it a little larger. Look at the lens through a polarscope,then you will see the excessive stress in the lens .This stress can cause distortions in an opthalmic lens.Since trivex "flexes" more than poly the potential for this stress is greater.This unwanted stress can also cause abnormal low abbe values in a given lens.

[bev]

Question: If there were "stress" lines, could that be why I seem to be having more problems with glare like in the true hot sun when the rays are reflecting off chrome and hoods of vehicles. I do not seem to see this as much with my old lenses (Is that because I am squinting more with the old lenses because they are out of focus and thereby reducing the glare myself?) I have noticed when I wear the new pair, I open my eyes more and everything is so bright that I want to cup my eyes to avoid the sun. It is similar to having one's eyes dialated and you see the brightness more. I tend to be very sensitive to the sun in my older age...... Also, even when lights are on behind me, I will pick up the glare on the inside of the lens as well. I went to church this weekend and all the lights were shining on my eyes. It kind of makes it like you were looking at something but a flashlight is shining on you at the same time. Any ideas?

[mshimp]

Outside in the sun you need a pair of polarized sun lens to cut that kind of glare. Inside ,the kind of glare you are talking about requires an anti-reflective coating.I don't believe the stress we have been talking about has caused any of these problems.

[Pete Hanlin]

Internal stress does not necessarily cause visually detectable aberrations. It doesn't in heat tempered glass (which has a pattern of stress in the form of a cross), it doesn't in polycarbonate (regardless of what certain manufacturers would love to have you believe), and it wouldn't in Trivex (which as a thermocure resin will not have inherent internal stress).

Flexure, which could be caused by an oversized lens, could potentially cause a noticeable visual disturbance (as well as inducing internal stress), but it would have to be severe. Trivex lenses, like polycarbonate, are very flexible- especially when the overall lens is thin (low powers). However, the lens would really have to be considerably oversized to cause sufficient flexure to be noticeable.

As to the perceived brightness, that is somewhat surprising, especially since Trivex tends to have a yellowish cast which would theoretically block more light than a polycarbonate lens.

Again, it may well come down to the orientation of the lenses to the eyes. Unless the lenses have been poorly processed, my guess is that adjustment of the fit should readily resolve the visual disturbances.

[mshimp]

There is no doubt that a heat tempered glass lens has induced stress for greater impact resistance.However I wouldn't compare glass products to plastic products in this way.Glass has superior optics with no flexure.It's like comparing apples to oranges. I'm certainly not recommending glass lens to you Bev. I still maintain my assertion that trivex lens are only good for drill mounts,and maybe rimless frames.This may be one of the reasons why essilor has not shown an interest in this material thus far.This opinion comes after processing hundreds of trivex lens.

Though I do agree with the comments that have been stated in regards to making sure the frame is adjusted properly and giving it some time.

[bev]

Thank you all once again for all the advice and suggestions. It really helps. I talked to my optomestrist who unfortunately has not heard of Trivex. He told me everyone likes Sushi and he does not. He said just because everyone likes Trivex and I seem to not is okay. He suggested I get what I want. Bearing that in mind, for whatever reason, my eyes tend to like the anti-reflective coating on the polys better. Perhaps I got a bad AR on my Trivex???? Still struggling with the decision of what is best for me.

My 13-year old daughter just got her second pair of glasses (when I got my new pair)and she too got the new Trivex lenses. Last night she asked me to clean her lenses because there were spots on the lenses (like tiny droplets of hair spray) and they will not come out for the life of me. I have gotten hair spray out of mine and out of her old glasses which were polycarb as well. I tried the cleaners I was given and the special cloth, and even used a portable wet wipe and cannot get the spots to go away or even diminish. Her frames are on the top but rimless on the bottom. Could these spots be coming from the inside of the lens somehow? I am already disgusted with Trivex.