Allekss If they become weak ( after prolonged screen time or other factors ) your muscles are stressing more to focus your vision and that's where we feel the eye pain. Vision therapy should improve and strengthen your eye muscles over time if properly done !!!
Thanks for the updates, guys. Unfortunately, my story is quite different. Eye therapy has strengthened my eye muscles and got me some extra "eye skills" (I can now converge and diverge better than the average person, according to the three specialists I am seeing), but has not solved my precarious visual condition. I cannot use Windows 10 version 22H2 on my laptop without terrible discomfort (whereas I can handle the same version with much milder symptoms on 2-3 PCs at work). After 10 years without a television I bought a Smart TV, purposely choosing a low resolution (FHD) one as I have normally more problems the sharper the image is. Sadly, my TV time is a torture and it typically takes a couple of days to recover from 30 minutes of use. Mystery, I can watch most TVs no problem when I am at the pub, by my parents, in the dentist waiting room. More puzzling, despite all my efforts I still cannot tolerate most LED lights. Just sitting under LED lights triggers symptoms that last days.
My specialists have been clear since the start. They told me that, in their opinion, doing eye therapy could improve my condition by only 10-20%. None of them has a clue as to the reasons of my symptoms. I keep doing eye exercises because I have no other way out, they do not harm and at least produce some form of relaxation. The most sophisticated ones can also be fun. I should also add that I took home all my eye exercise gadgets last Christmas, and test my siblings' eye ability. To my shock, they could get everything right straight away. However, my brother-in-law, who has zero visual discomfort using electronic devices as my siblings, couldn't absolutely figure out how to successfully use a loose prism or a stereogram, which reinforces my opinion that heterophoria isn't enough to justify all I have been thru in the last years.