So I figured I'd chime in here. Draw whatever conclusions you want but I'll try to elaborate on the onset of symptoms as well as severity.
I'm 41. I'm overweight. I have in the past couple years made some concerted efforts to lose weight and hit my target goal. I practice kenpo karate and will never reach second black if I don't lose like another 25lbs. so there's that.
When I am more fit, I notice my eye problems less. Although that isn't a universal truth - some screens hurt NO MATTER WHAT. It's possible that my tolerance is higher for discomfort in general when I'm more fit. Or, it's possible that fitness brings with it less time spent in front of screens.
I have high cholesterol, but it goes down with weight loss so once I reach my goal weight the numbers should be good for that also. No other abnormal blood work.
I have mild anxiety. Martial arts helps. So does getting enough sleep.
I have a fast heartbeat. Have had it since I was a kid. It's hereditary/congenital. And harmless.
I have TMJ and Bruxism. However, I've worn a nightguard for TMJ - and had TMJ flareups - for years. And never had a problem with any screen of any kind before 2012. Maybe the very tail end of 2011. But I was treated for TMJ long before that. How severe my TMJ is bothering me doesn't seem to correlate at all with my eye issues.
I suffer from allergies. Both seasonal and specific. I'm sensitive to sulfur compounds (found in natural gas exhaust) as well as molds and grass and tree pollen. Again, there seems NO correlation between allergy symptoms and eye problems.
I have tinnitus. Inflammatory, not nerve damage. It's related to the TMJ. It also seems to not correlate with eye issues.
I consume caffeine (a couple big cups of coffee a day) and alcohol (a drink or two a couple nights a week) but neither in excess and neither seems to correlate.
I don't smoke, consume drugs, or even take very many over-the-counter medicines (although I used to be a bit of a vitamin junkie, I gave that up once the science started coming in on it).
I see a chiropractor for neck/spine alignment issues (years of computer work combined with a midlife fascination for getting my ass kicked in the dojo). How well my spine is doing also doesn't seem to correlate.
I do go through swings. In late 2012 and very early 2013 it was the worst. I had nights where my eyes were so strained I simply COULD NOT SEE. Parts of 2015 and 2016 were much better. Late 2016 has seen a return to form. Nothing in my life - fitness, activity level, illness/injury - really seems to correlate.
I do wear progressive glasses. Beginning in 2015 these were needed. My prescription is roughly -5/+1.5, or -4.75 if wearing standard lenses. No astigmatism.
In 2001-2002 I became dreadfully ill from food poisoning. Long story short I "starved" for about 8-12 weeks. During this period my tinnitus/inflammation flared up badly, as well as my vitreous layer in my eyes separating. This is a normal thing that happens to everyone, but usually not at the age of 26. Usually more around 40-45. The illness might have been a trigger, or it might be coincidental. Either way I recovered fully, and had no visual issues (other than floaters in the vitreous layer) for a decade.
If anyone sees anything in here they'd like clarification on, or that they think might help, let me know.