they have degrees, so why am i diagnosing myself?

There are many different types of doctors in our world. Different doctors who specialize in different fields. I regularly use three specific types of doctors: personal care physician (PCP), dentist, and optometrist. Before I go on with my post, let me say that I have a great deal of respect for all three. Now that this obligatory disclaimer is out of the way, let me continue. Doctors go through years of studying and training before they are able to join or start a practice. They generally have walls laden with degrees and other credentials. Why is it then, that sometimes much of their diagnosis is completely dependent on me? It's as though I essentially diagnose myself and they just interpret it for me. Don't get me wrong, they are a big help, but sometimes, I feel like too much of their diagnosis is dependent on me. I mean, I understand the fact that a PCP needs to ask me to relate my symptoms to him because he cannot establish what the problem is if he doesn't know what I'm experiencing. This one doesn't bother me so much. And I understand that a dentist needs to ask me to inform them if I have pain because they cannot feel my pain. They find cavities with or without my help. Really, it's the optometrists that this blog is about. They sit there and turn little lenses until I tell them when I can see. I know that they cannot see through my eyes, but I still hate it. What if I'm wrong. What if "A" was clearer than "B" and I misspoke. There is way too much pressure on me. I understand there's no way around doctors needing to ask me questions so they can properly diagnose me, but with all that studying and with all those degrees, I wish there was a better way. But, as they say, such is life.