guys guys guys hear me out
What if the reason Qifrey is going blind isn't because he was blind before - it's because the silverwood tree literally bleaches him of pigment.
Walk with me here. Lack of pigment in the eye can cause photophobia (sensitivity to light, glares) and iris transillumination (excess light entering the eye). Both cause significant discomfort and severe vision issues even in normally lit conditions.
Both also have long-term adverse effects, as the retina is damaged by long-term exposure to light (source)(yes it's wikipedia, who are you, my highschool english teacher? sue me)
Qifrey's vision issues have to do with specifically light senstivity, after all.
And we can see that one of the adverse effects of the silverwood tree is leaching pigment - it's the first thing Qifrey notices about Custas.
We also know that these effects are made vastly worse by coming back from partial tree-ification: Custas' hair goes white after he nearly fully trees out and is brought back, and we know for a fact Qifrey has been pushed to the point of tree'ing several times and had his mind wiped several times before he is found in the coffin.
I thought I was being paranoid at first, but look at the covers Qifrey features on as well:
His eye IS getting paler. They're more silver than they are blue in the volume cover of 12 vs the volume cover of 3.
All this was started because it makes no sense to me why the silverwood wouldn't "fix" the eyesight the way it fixed his shoulder or Custas' legs if that was truly the reason why he was given the seed in the first place:
Now you could say "well he doesn't remember, that COULD have been the reason", but I genuinely don't think it is. After all, he has it to thank for both of his eyes.
By living with the parasite for so long, it's leaching everything from him - but it's also forcing him to slow down. Taking his eyesight is in the parasite's best interest in the way that it forces a person to settle. That's just side-faff though.
Another thing pointing to loss of pigmentation causing all this:
When the branches are healthy, they're silver white.
yeah anyway thanks for coming to my ted talk i am so normal about this manga