I am sorry you are going through this. I am on plaquenil, too, though for different conditions (but I do have mild sjogren's syndrome.) Your best bet for finding answers on Lupus is in the Lupus forum here on medhelp. While we do get some folks with sjogrens here in the arthritis forum, many more post in the autoimmune conditions forum.
It's good to get a base line on your eyes when you start plaquenil. That helps them have a starting point to compare to when you get your annual check up - essential while you are on plaquenil. My eye doc told me that if problems are experienced it is usually after 20 yrs of taking the medicine, but that there are exceptions and so each year your eyes should be checked. I have 2 side effects from this drug. First, sometimes my eyes have trouble focusing. I rest them (close them) for a few and then try again. That usually does the trick. Second, I get some crazy vivid dreams. Really vivid. Almost real. Other than that, I have done fine with the med. I am told it can cause you to lose weight, but the other meds I take can cause you to gain so apparently that is a wash - would be nice to pick and choose our side effects! I would keep the vivid dreams though. Sometimes they are nice.
Oh forgot to add that I have torn my left and right calve muscle in less than 8 months. Can this be related