@frozenborderline @GlassCannonLife It might be wise to start troubleshooting vision problems by seeing an eye doctor. At the very least, they might be familiar with things that might cause vision problems, whether or not they originate in the eye.
This is a list of problems that cause changes in eyesight. It is not comprehensive, but there are a few decent ideas here:
"What Causes Sudden Blurry Vision?"
https://www.healthline.com/health/eye-health/sudden-blurred-vision#other-causes
I had a similar problem in the last year, with reading on paper or a computer screen or while driving became more difficult because of blurry vision. I went for a "regular" eye exam, and the doctor was concerned about my blurry vision and sent me for an evaluation by an eye surgeon. He diagnosed me with epithelial basement syndrome, which is caused by wrinkles in the underside of the cornea, as well as cataracts, even though I'm on the young end for them. Eye drops and ointment in the eyes at night helped a bit, but I will have two eye surgeries in the short term to scrape stuff off corneas, and then cataract surgery at some point.
The cataracts can be caused by oxidative stress, a problem known to exist in most ME/CFS patients, and the other problem is just bad luck, it's not uncommon, up to 20% of adults have it at some point.
I also learned that some of the infections known to haunt ME/CFS patients can affect vision, like HHV6, for instance.
"Recurrent ocular surface inflammation associated with human herpesvirus 6 infection - PubMed"
https://pubmed.ncbi.nlm.nih.gov/24296955/
Surgery on the spine has been linked to vision loss through optical nerve damage.
"Vision loss after spine surgery: review of the literature and recommendations in: Neurosurgical Focus Volume 23 Issue 5 (2007) Journals"
https://thejns.org/focus/view/journals/neurosurg-focus/23/5/foc-07_11_15.xml?tab_body=fulltext
Nutrient deficiencies such as vitamins A and B12 can cause vision problems.
"8 Nutrients That Will Optimize Your Eye Health"
https://www.healthline.com/nutrition/8-nutrients-for-eyes#TOC_TITLE_HDR_3
If none of the above seem to be an issue, seeing a neurologist might be helpful.
Best wishes in figuring this out...