a tiring optimist?

I was flipping through the channels the other day and saw a little snippet about the TLC special on Michael J Fox titled “The Adventures of an Incurable Optimist.” Now, we all know that Michael J Fox has a rare case of Parkinson’s disease. In my Neurology class I have learned a bit about this disease. I know that Parkinson’s is caused by the neurotransmitter Dopamine not being absorbed by the Basal Ganglia (along with a few other brain parts like the Subthalamus). There is medication for this, an artificial type of Dopamine, but the thing with the medications is, it only works for about 5 years, and it just masks the problem, so in 5 years, when the Basal Ganglia will no longer absorb the artificial Dopamine all the symptoms come back; only, their worse. They’ve been progressing over the past 5 years and you just haven’t been able to see them. Now, doctors tell you this when they diagnose you and prescribe the medication. Naturally, most people opt to take the medication. Five years is a very long time to live while facing an incurable disease. Most people aren’t diagnosed with this disease until later in life; so 5 years is even longer to live “normally” when you’re only looking at only 10 or 15 years left in your lifespan anyway. Mr. Fox’s condition is a very rare form, and he was diagnosed at a very young age. He has a very long time to live with this condition. Apparently this TLC special is about his fight in all of this; lobbing Congress for research funding, and his fight to stay positive through it all.
(Sorry for the long intro)
Watching this snippet left me wondering, were do we draw the line between being an optimist and being a realist. When do you stop seeing the silver lining? Do you ever stop when facing a problem such as this? Can you still be an optimist while taking in the entirety of the problem? Can you be an optimist and not just minimize the problem? Where does the balance rest?