I have filed a bug on Ubuntu Launchpad to try and disable dithering, it's not been assigned to anybody yet but I will keep checking back for updates.
I've also been posting on some subreddits (/r/strabismus, r/optometry) to try and get advice from others, unfortunately there has not been a big response.
I'm not giving up, but (part rant) I'm fed up of this BS. I haven't been employed for quite some time now, why would I want to work on a computer all day if I'm 'stuck' on my good machine which is over a decade old? My lovely new NUC is sitting here which would be a real aid to my personal life (music production/graphic design) and also as a media player/games console. Even on good devices, it seems that app by app or update by update, things are breaking and becoming unusable fast.
I'm not trying to sound pessimistic, but we can't live on years old software and hardware forever. I understand that everybody has their own lives but how do you all work right now? Don't you get really bad symptoms?
If I went to a doctor today and said "I can't work in an office anymore because of XYZ causing me eye strain" - as it's not even a medically recognised condition, I get no support from the state (I'm based in the UK). I could get a job away from technology (a cleaner, teacher, shop assisstant) however I shouldn't have to resort to this much of a change, just because of a software update.
I may be a part of a minority, and I'm very grateful that we can share our experiences, but these companies have so much to answer for if updates are causing individuals like myself to have these sort of reactions.