Ivermectin 12 mg 4Xd ? That's 48 mg a day total right?
What is your weight? The dose you are taking is for a huge person.
The vet version of this drug ruined my vision and I only took about 22.5mg and I was around 185LB when I took it. Many others do not have this reaction though. Maybe I just very sensitive to it or something else happened. Nothing showed up on the brain MRI and ophthalmologist tests. I don't have parasites or parasite remains on my head or eyes showing on tests.
Look up "ivermectin dyschromatopsia" on google and/or the document titled
"A randomized, double-blind, controlled trial of
the effects of ivermectin at normal and high
doses, given annually or three-monthly, against
Onchocerca volvulus: ophthalmological results"