Legend of Glass

[sportywei]

Hi all,

What are ophthalmic factors that could affect the central image quality of our ophthalmic lenses?

Maybe
1. Abbe Value
2. lens thickness ??
3. base curve ??
4. Material ??
5. Birefringence

In Singapore, most opticians would say that all mineral lenses would perform better in comparison to organic lenses. Is that true or just a myth?

Cheero:hammer:

[Chris Ryser]

In Singapore, most opticians would say that all mineral lenses would perform better in comparison to organic lenses. Is that true or just a myth?


Of course, glass is better..............but plastic materials are easier to work with and make more money..................

[drk]

1. Lens power
2. Lens optical design
3. Lens material
4. Application thereof

[For-Life]

I have not met someone who can tell the difference in visual quality between glass and plastic

[braheem24]

In a polarized sunglass, it's a noticable difference.

[chip anderson]

For Life: Meet someone who wore glasses or was in the optical business before 1960. Look at a pair of glass spectacles 8 years old, look at a pair of plastic (any) spectales over 4 years old.

Chip

[For-Life]

In a polarized sunglass, it's a noticable difference.

I have had polarized serengetti's and polarized plastic & poly. I cannot tell the difference

[For-Life]

For Life: Meet someone who wore glasses or was in the optical business before 1960. Look at a pair of glass spectacles 8 years old, look at a pair of plastic (any) spectales over 4 years old.

Chip

yeah, then look at their bridge

I had one guy wear glass all of his life. A few years ago they switched him into plastic. He came into our office and insisted glass. 6 months later he came back and wanted it switched back to plastic.

Yeah, with glass he could clean his glasses with the dirtiest rag, but seriously that is just a ridiculous provision. When it came down to it he loved the weight of plastic.

[UFRich]

I have worn many brands of polarized sunglasses. The glass provides a much crisper, clearer view of the world. The polarization always seems to be less effective in plastic.

[DragonLensmanWV]

I have worn many brands of polarized sunglasses. The glass provides a much crisper, clearer view of the world. The polarization always seems to be less effective in plastic.

Try it in a grooved rimless.:D

We use the Younger Nu-Polar and have not had any delams, even in grooved rimless.

[braheem24]

I have had polarized serengetti's and polarized plastic & poly. I cannot tell the difference

If you couldnt tell the difference between plastic and poly, then there's no difference to you between plastic and glass.;)

[For-Life]

If you couldnt tell the difference between plastic and poly, then there's no difference to you between plastic and glass.;)

pretty much true. I personally believe that many of the differences between them are over exaggerated. Saying that, I do know that the processing of poly differs, and some are cleaner than others.

[Frank V. Scallio]

There are three reasons why we sell plastic or poly today. More profit, lighter weight and because of lawyers. I have been in this field for 32 years and I remember glass well. Glass is optically superior to plastic in many ways. First it doesn't warp, second you can actually edge it better and the lenses don't fall out like in low Rx's like plastic or poly. Third it doesn't yellow and fourth its naturally hardcoated and accepts AR better than any plastic as it doesn't expand or contract due to heat.

I wear plastic or high index because I like the weight but I know glass is better to look through. Glass unfortunately cannot be edged into todays modern frames such as rimless or drill mounts. Heck even todays large sunglasses are out of the question because of the weight.

I still sell a few glass half eyes, but I always get them surface with very flat bases and knife edges for the old timers. Pt.'s love them because they never seem to scratch!

[MarcE]

There are three reasons why we sell plastic or poly today. More profit, lighter weight and because of lawyers.

Kinda, but not really.
UV blockage, Patient safety, more options (like you mentioned, rimless, drills). When I think of glass lenses, I worry about the safety of the patients eyes, not being sued. I make more money on glass because I charge a premium over poly. I charge the same as Trivex. Although I probably make less profit because the people that want glass are the ones that don't want to return for an eye exam or new specs for 4+ years.

A guy came in recently with a broken lens. He handed me the shards of glass. 0.7mm CT in obviously untempered glass! (lenses were made in Africa) Yes, he got some in his eye. Fortunately he's OK. I know that isn't going to happen in the US, but glass is still not safe enough for me not to worry about our patients.

BTW, I don't dispense but a small smidge of glass, but I can tell a difference between polarized glass and polar poly. Glass is clearer. I don't know if I could tell a difference between polarized plastic and polarized glass, or polar poly and polar plastic.