hpst I seem to have the same disturbs as you. And I agree on dividing between CVS and this other disruptive thing we are suffering from. As said multiple times, I get strain almost instantaneously in front of a "bad" device. It is definitely not overuse. And I do not even need to "converge" and focus my eyes anywhere, because simply staring at a desktop without reading anything bothers me. It looks like a strong allergic reaction. And the effects may take days to fade. In my case I am also quite sensitive to non-incandescent lightning, although I find very tricky to say what is worse between LED and fluorescent light. It seems to be very dependent on the lamp/situation every time.
As to the convergence matter, I know my eyes are not "perfect". However, almost 15 years ago I was shown some convergence exercises by a very good optometrist. I quickly improved a lot. 4 years ago I attended a 2 day vision therapy session by Leo Angart I posted about months ago (https://www.vision-training.com/e/index.html). We were about 20 people of any age. Some guys had incredibly thick glasses and huge vision problems, like they could not even see me clearly from a meter without spectacles. After a few hours introduction, we did exercises similar to the ones I was shown by that optometrist 15 years ago. As Mr. Angart had anticipated before beginning the training, many of those people had to go on the same day to a pharmacy buy cheap glasses with reduced diopters. They could not use theirs anymore. They and I who witnessed that could not literally believe our eyes. Some people had to buy again a new pair of glasses after the second day, which was fully focused on training. Now, here comes my point. I went to that therapy session for curiosity, despair - given no eye doctor could figure out my problem - and to explicitly inquire about my computer-related eyestrain. I asked everyone around me and none of those guys, young or old, who came in with glasses thick like a bottle on the first day and with huge convergence issues, had any eyestrain from computer besides the CVS symptoms hpst mentioned (overuse etc. etc.). Mr. Angart suggested blue light was my issue and told me LED screens were not known to flicker like CRTs (BenQ had just come out with flicker-free LED monitors though!). How come I was the one in sorta better eye shape there, but the only one who would go bedridden after seconds of modern device usage? That is another reason why I believe convergence exercises are great, but are not going to solve my problems ever.
It has been awful for me the last couple of weeks. I kept my phone off for 5 days but now my MacBook Air is driving me crazy too. For some reasons some updates passed thru although only at Office level, and I cannot explain why they would affect my display. I am hoping I am just over-worrying. I noticed in the past that a sinus attack or a flu which I just did affect my eyes, but I feel I am just finding excuses. It is the device again.
I have been long enough but since this thread is about treatments, I would like to add a couple of things. I have been sleeping little, like 3-4 hours a night for long, even if I use UVEX goggles while working on my laptop at night and run f.lux at 4600 K during the day and 1900 K from sunset. The 5 days I did not use my laptop while on holiday I could sleep properly. The day before yesterday I took two pills of 50 mg diphenhydramine hydrochloride and I could sleep. I woke up a bit stoned but the twitching of the muscles around my eyes was greatly reduced and using my laptop resulted less harsh. Today I am back to awful symptoms. What does that mean? Is it neurological?
Finally, in the last few weeks I have been doing acupuncture treatments to cure headache, sinus inflammation and insomnia. I did not specifically mention eyestrain to the therapist. Well, I do not know if the recent worsening of my eyestrain could be ascribable to that, but I doubt. Has anyone tried acupuncture against eyestrain?