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What is the difference between carboxylmethylcellulose/carmellose/CMC (Refresh Tears) and hydroxymethylcellulose/hypromellose/HPMC and polyvinyl alcohol - povidone (PVA/PVP)? (I have no medical training so pardon any mispelling!) It seems like CMC works better (for me) with Focus Night & Day (which I am currently trying) and PVA/PVP works better with Proclear, except that my eyes burn after awhile. Back when I used to wear PMMA lenses (25 years ago) HPMC and PVA were used in contact lens wetting solution.
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Is there a chemist in the house?
Wow, I wish I knew the answer to any of this. All different polymers and I have no idea specifically what the differences are between them.Originally posted by aLensUsr
One thing I do want to mention however is that even with specific ingredients, there can be substantial differences in the products that contain them as active ingredients, both because of differences in the concentrations and also in the grades of the ingredients themselves (which aren't normally specified on the labelling). Based on my personal experience with various PVA and/or povidone drops, for example, not all PVAs are created equal, by a long shot.Rebecca Petris
The Dry Eye Foundation
dryeyefoundation.org
800-484-0244 -
Homes may have been the closest.Is there a chemist in the house?
Don't trust any refractive surgeon with YOUR eyes.
The Dry Eye QueenComment
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Hi there,
I find this question quite interesting as I asked my Dr. the difference between Hydro eye and Bio tears I was holding a bottle of each in my hand at the time of question, with a list of the ingredients. They are identical except one in the Bio tears was not listed on the Hydro eyes. I was told that this other "item" is the "delivery vehicle" to introduce the other ingredients into you system. It sounds good.
JeffComment
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