In my case and after much much experimentation and doctor opinions, 80% of my problem is vision and perhaps 80% of that is convergence.

It took me a long time to realize this. A set back made me realize who converging has been causing all these symptoms. They happen with a lag in my case so it is hard to tell what is causing what. But what I did not realize earlier was how much better I can feel if I did not converge. For two years I did not have more than 3 good days in a row.

Now that I am off work, I can have as many good days as I want, it is my decision: to read or not to read... as simple as that.