[masraum]

I have no actual experience. I can't say about your wife's brand, but my wife had lasik or one of those sort of things, and then also had cataracts, a retinal tear with a resulting vitrectomy. The Drs always said that whatever drops you got, they should always be the preservative free version (my wife always used Refresh brand)

And one additional note/question. Are you talking about Systane Ultra vs Systane Ultra Preservative Free, or are you talking about one of the other Systanes that's preservative free. Systane makes several different types, systane complete PF, systane ultra PF, systane hydration PF, and systane original PF.