Good points here. When I was 61, I began to have occasional double vision. Several doctors looked at me and figured it was stress or one thing or another, and it would go away periodically so I'd forget about it. It took another couple of years and increasingly severe symptoms before it was diagnosed as myasthenia gravis. It was obvious once they found it, but MG only occurs in from 2 to 10 people per 100,000, depending on whose numbers you believe, and many things cause similar symptoms. I actually suspected it early, because I had a friend in high school whose mother had it, but it's pretty rare in men and the docs thought I was suffering from an overdose of WebMD.
Not much harm done in my case, because they can only treat the symptoms, not catch the condition early and cure it.