Purple,
I have been following your posts for a while, and I have some comments to make. Remember that I'm an outside observer and can maybe see the "big picture" while someone closer to the situation (you) can't. Or maybe I'm totally off base
First, I know you love your doctor, and you have faith in him and in Dr. O'Brian. I know they are trying their best to help you. But they have only made you worse. The cycle of drugs you are now using is just amazing. You take one drug, get side effects, take another to counteract the side effects, take a third to counteract the side effects from that one, ad nauseum. Meanwhile your eyes get sicker and sicker. Please consider getting another opinion from someone else. There is no ONE expert in any field. Dr. O'Brian might be great for most people, but maybe not for you. Don't take any one person's word as gospel, especially since you are NOT getting better. And yes, I realize that there isn't a cure for simple dry eyes, but you are at a different level altogether. Your fellow dry-eye sufferers aren't going through what you are, in my opinion because they aren't being overmedicated. Sometimes it sounds like (and I mean no offense) that they almost have you brainwashed into believing that you need all the drugs that you use.
Second, it may be worthwhile for you to investigate alternate forms of medicine. It wouldn't hurt to see a naturopathic physician, at least just to see what he or she has to say. I think modern medicine is great, but all physicians know is to hand you drugs. "Here, take this." "Oh, you got bad side effects?" "Take this drug then!" "You're worse? Put this drug in your eye too!" How long are you going to let this cycle go on? They don't even know exactly what is wrong with you and they really aren't trying to find out. They're only treating symptoms, some of which they are causing by the drugs they are giving you.
Just my opinion

I hate to see you sitting there suffering, week after week. Find someone else who can actually help you.