My eyes are healthy but what is causing the discomfort? And now that my prescription is stronger, why am I still getting it after I take off my glasses? I don't get this when I'm wearing them. Why?
I am not sure if this is going to help you but I can share my experience with you.
Eyestrain usually causes aching sensation around and behind the eyes. After these first sensations symptoms of eyestrain can progress into a generalized headache. For me it was very painful when I was trying to focus my eyes. My doctor has informed me that eyestrain is usually a result of overuse of the eyes for some activities which are requiring close and precise focus. These activities include reading, sewing or using the computer.
I have this problem because my work is related to my computer. I have bought one of those filters and I am trying to look away from the computer from time to time. I hope this was helpful.