I returned to this topic after some time since MDMA caused me some visual snow again, and I had to fix it (not fully, but to a minimum) on LSD by watching the video I posted, so I remembered I posted here. Of those calibration tools, only the flicker has strong positive effects on visual snow, reduction of colourful blobs in the corner of vision and palinopsia. My vision seems faster and less laggy after just two hours of committing to watching it sober, and it seems to last (I know I said the video I posted reduces palinopsia, but I was mistaken; it was just a placebo effect since OP claimed that, but this time, I'm sure). I found out it works best when combined with the video I posted for visual snow reduction (alternate between watching one and then another). While watching it, I moved my head while having my vision focused on the colourful blobs in the corner of my vision for maximum effect. Next time, I will trip on acid again somewhere in October (I trip regularly now since I'm not scared of HPPD worsening anymore), I will commit fully to calibrating my brain with the flicker, but I expect a strong positive result.
Other screen tests had no effect after I tried watching all of them for 5 minutes.
I feel so sorry for people who have so much trust in Science™ and (((pharma))), that they think the cure for HPPD is in medications, which slow down the brain so much that they have some positive effects on HPPD but also having a lot more negative side effects. Calibration of the brain seems to be the key to reducing HPPD symptoms.