So I received my eyepatch 2 days ago and have been using it for all screens since (on my "bad" eye). Seems to give me a massive improvement. ("seems" because it may be placebo, and because it's too early to tell for sure).
I went to a BVD specialist, they diagnosed me with astigmatism but no BVD.
Interestingly, I have the exact same symptom as @bkdo ("text getting slightly vertically doubled when my eyes are very fatigued") that he corrected via prism lenses, but I don't have BVD so no prism lenses for me.
Here's my new theory for my screen strain and eye patching:
- The astigmatism (which is much stronger in my left eye) leads to left-eye fatigue because the eye is constantly trying unsuccessfully to focus properly. The wikipedia page for astigmatism says: "symptoms can include eyestrain, headaches, and trouble driving at night")
- The eye patch lets that left eye not try to focus at all, which fixes the above.
- Still not sure why the problem happens only with screens
Planning to go to my personal ophthalmologist for a prescription for astigmatism glasses in about a week (the BVD specialist wouldn't give me one).