It sounds frightening to have the eye symptoms and not know what is causing it. It sounds like your physician(s) have done a thorough workup.

I had eye symptoms similar to what you described when my symptoms first started. I did describe it to the eye doctor as feeling like my vision was distorted. It usually was only in certain directions of gaze and did get worse towards the end of the day. As it turns out, when I went to see the neuroophthalmologist he was able to determine that it was actually minor double vision that I was experiencing.

I hope you get some answers soon.

Cate