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Wow, cannot upvote this comment enough. Super helpfull, thanks! Definetely going to go with uncoated lenses. Will the opticians even know what I'm talking about

Wow, cannot upvote this comment enough. Super helpfull, thanks! Definetely going to go with uncoated lenses. Will the opticians even know what I'm talking about when I ask for CR39? I have one concern though I'm - 6 Dioptre on each eye. so lens weight has always been an issue for me. even a few grams extra make a big difference. I always go for rectangular low profile lenses with the greatest thickness reduction they can apply and they always advise for Polycarbonate lenses. What's your take on this?

mrob 8y ago
All glasses are a compromise in some way, so you have to decide which flaws are most tolerable to you. -6 is strong enough correction that I'd seriously consider contact lenses if I needed it. Contact lenses avoid the image distortion and shrinkage you get with glasses, and because they move with your eyes, the image is sharp in all parts of your field of vision. Polycarbonate is IMO a terrible material for corrective lenses. It has very bad Abbe number, so you get a lot of chromatic aberration (rainbow artifacts) and it's very soft, so coating is pretty much required. Its only real virtue is impact resistance, which is important in safety glasses, but you can get flat safety glasses that fit over your corrective glasses. The weight is marginally better than CR-39, but not enough to make up for the poor optical performance. I haven't seen it person, but going by the numbers, Trivex seems superior. Wikipedia has some information on common materials: https://en.wikipedia.org/wiki/Corrective_lens#Lens_materials https://en.wikipedia.org/wiki/Corrective_lens#Lens_materials My preference for uncoated applies only to CR-39. Other materials have properties that make coatings more important. It's also possible that some coatings have much better resistance to cleaning than others. Unfortunately, details about coatings are generally secret, so there's no way to evaluate them.
- glaberficken 8y ago
  I see, thanks for the advice again I will read more about it. Yeah i wear daily contacts for beach / swimming days, but unfortunately never managed to get used to wearing contacts as primary everyday correction.

mrob 8y ago

All glasses are a compromise in some way, so you have to decide which flaws are most tolerable to you. -6 is strong enough correction that I'd seriously consider contact lenses if I needed it. Contact lenses avoid the image distortion and shrinkage you get with glasses, and because they move with your eyes, the image is sharp in all parts of your field of vision. Polycarbonate is IMO a terrible material for corrective lenses. It has very bad Abbe number, so you get a lot of chromatic aberration (rainbow artifacts) and it's very soft, so coating is pretty much required. Its only real virtue is impact resistance, which is important in safety glasses, but you can get flat safety glasses that fit over your corrective glasses. The weight is marginally better than CR-39, but not enough to make up for the poor optical performance. I haven't seen it person, but going by the numbers, Trivex seems superior. Wikipedia has some information on common materials: https://en.wikipedia.org/wiki/Corrective_lens#Lens_materials https://en.wikipedia.org/wiki/Corrective_lens#Lens_materials My preference for uncoated applies only to CR-39. Other materials have properties that make coatings more important. It's also possible that some coatings have much better resistance to cleaning than others. Unfortunately, details about coatings are generally secret, so there's no way to evaluate them.

glaberficken 8y ago
I see, thanks for the advice again I will read more about it. Yeah i wear daily contacts for beach / swimming days, but unfortunately never managed to get used to wearing contacts as primary everyday correction.