He writes:
Pluronic 17R4, it turns out, is one of a family of chemicals made by BASF. Opti-Free RepleniSH uses a different chemical made by BASF, Tetronic 1304. Both are surfactants - substances that act on the surface of chemicals (typically water). Though they have many roles, they're often used to help dissolve oils or proteins, and you can probably find surfactants among the ingredients of household cleaners and detergents.
While I assume the Pluronic in Clear Care is essentially there as a cleaning agent, the one in Opti-Free RepleniSH apparently also bonds water to the surface of silicone contacts, making them more comfortable. That's probably why Alcon describes the combination of the Tetronic and another, generic surfactant as a
"reconditioning system", though I don't doubt that part of the reconditioning is cleaning oil and protein from the lenses.
While I assume the Pluronic in Clear Care is essentially there as a cleaning agent, the one in Opti-Free RepleniSH apparently also bonds water to the surface of silicone contacts, making them more comfortable. That's probably why Alcon describes the combination of the Tetronic and another, generic surfactant as a
"reconditioning system", though I don't doubt that part of the reconditioning is cleaning oil and protein from the lenses.
With regard to the history of Clear Care...
I enjoyed your write up on Clear Care, but it's missing an important point. Since I didn't see a way to comment on the blog, I'll have to mention it here.
Long before Clear Care, back in the 80's, Ciba Vision marketed AOSept. It was essentially purified 3% hydrogen peroxide with buffers to manage pH and saline, just like Clear Care. It used the same case with platinum catalyst as Clear Care currently uses, although the early cases had the catalyst disc packaged separately. But the biggest difference between AOSept and Clear Care is that Clear Care has a cleaning agent added, Pluronic 17R4.
With AOSept, you needed to use a separate cleaner. I mostly used Ciba's Miraflow, though there were alternatives. You also had to use saline to rinse off the cleaner, because residual cleaner caused the peroxide to bubble too fast, flowing out of the vent hole. Yes, AOSept had bubbles, but it didn't clean the lenses. When single-step solutions came out, AOSept's three step process lost market share. It took Ciba a while to find the right cleaning additive.
Although Ciba's marketing material promotes the bubble action - and for all I know, it may be absolutely true that the bubbles help clean - obviously the Pluronic 17R4 is critical. Otherwise Ciba would have just sold AOSept as a single-step product.
Even with the cleaning agent, Clear Care doesn't do the best possible cleaning. Perhaps no single-step solution does. When I first started using multifocal contacts, my optometrist advised me to go back to using MiraFlow and saline to extend the life of the (expensive) multifocals. Apparently what made the lenses "monthly" lenses wasn't that the lenses wore out, but that standard single-step solution regimens would leave enough deposits accumulating on the lens after a month to be uncomfortable. The MiraFlow allowed me to stretch the useful life of the lenses.
Long before Clear Care, back in the 80's, Ciba Vision marketed AOSept. It was essentially purified 3% hydrogen peroxide with buffers to manage pH and saline, just like Clear Care. It used the same case with platinum catalyst as Clear Care currently uses, although the early cases had the catalyst disc packaged separately. But the biggest difference between AOSept and Clear Care is that Clear Care has a cleaning agent added, Pluronic 17R4.
With AOSept, you needed to use a separate cleaner. I mostly used Ciba's Miraflow, though there were alternatives. You also had to use saline to rinse off the cleaner, because residual cleaner caused the peroxide to bubble too fast, flowing out of the vent hole. Yes, AOSept had bubbles, but it didn't clean the lenses. When single-step solutions came out, AOSept's three step process lost market share. It took Ciba a while to find the right cleaning additive.
Although Ciba's marketing material promotes the bubble action - and for all I know, it may be absolutely true that the bubbles help clean - obviously the Pluronic 17R4 is critical. Otherwise Ciba would have just sold AOSept as a single-step product.
Even with the cleaning agent, Clear Care doesn't do the best possible cleaning. Perhaps no single-step solution does. When I first started using multifocal contacts, my optometrist advised me to go back to using MiraFlow and saline to extend the life of the (expensive) multifocals. Apparently what made the lenses "monthly" lenses wasn't that the lenses wore out, but that standard single-step solution regimens would leave enough deposits accumulating on the lens after a month to be uncomfortable. The MiraFlow allowed me to stretch the useful life of the lenses.
Can you explain a bit more about the Pluronic 17R4? I'm not sure I exactly understand it...
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Please look at reviews on amazon.com of the HydraGlyde product out now. I just returned the one I had purchased after noticing "halos" around lights at night and feeling like I was in a fog or haze during the day. After realizing it was a new solution causing this I researched it and found out there are a LOT of people experiencing the same issue.
ReplyDeleteLate to this thread but this is important and must be shared. I’ve discovered the common thread linking the sensitivity resulting from the use of many contact lenses, CL multipurpose solutions and even some hydrogen peroxide systems - in my case - is the polymer, polyvinylpyrolidone, also known as Povidone and PVP among a host of other aliases and trademarked brand names such as Hydraglyde. I’m extremely sensitive to PVP and exposure has expressed in several manners. After emergency postpartum surgery, I experienced a 6 week chemical burn and recovery internally and externally from Betadine, an Iodine and Povidone solution that was used as a preoperative scrub. I assumed afterward it was an iodine allergy and avoided its use. Then came the chronic eye problems, the latest being severe corneal edema with temporary uncorrectable visual acuity, hives and difficult breathing. Thus, the quest for answers to my eye discomfort, declining visual acuity and allergy symptoms began. Since switching from RGP to the etafilcon A biweekly CL, Acuvue 2, I have tried every multipurpose solution and all of the hydrogen peroxide cleaning systems on the market. I have also attempted to switch lenses to several silicone hydrogels with better permeability and hydrophilic properties in an effort to find compatibility and comfort. My experimentation only yielded the continuation of the misery. So, I became proactive. I called the manufacturers and read the labels of every solution and every contact lens I had ever used and there it was. All of the new lenses and solutions shared the common polymer, polyvinylpyrolidone, which is often disguised in name as a trademarked moisturizer. I’m a 67 year old woman who has been a contact lens wearer since the age of 10. I began with hard lenses and have worn RGP, extended and soft hydrogel so I do speak from experience. Technology has its place but artificially manufactured normal tear and eye composition has not been an advancement for my particular biochemistry. I hope that my experience and the information that I have gleaned will be helpful to others. If you’re having ocular discomfort, blurry vision or any other signs of sensitivity, it could be due to a PVP allergy which is considered “rare” according to the corporate research documents (always consider the source). While it may be rare or as I believe, unrecognized and underreported, it has become an anaphylactic event as documented in several case studies readily available via an online search. My advise? Be very careful, be curious and be your own advocate.
DeleteThank you for posting. I'm tired of all the artificial, unnatural chemicals in food, cosmetic, etc. I just purchased RPG contacts I want to go back to older materials. I'm thinking of just soaking them in 3% peroxide and rinsing with saline.
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