The same online acquaintance who wrote about MiraFlow filled me in on a little bit of history of Clear Care, and talked about what the ingredient Pluronic 17R4 does exactly.
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.
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.