Interesting. I never realized it, but I can see the yellow "brush" bits but I guess its not related to my strain cause because I see it on the good old CCfl laptop with a TN panel (brush tilted at a 135deg angle as expected) and on the old iPad (at 90deg as expected) and those don't strain me at all ever. One more thing I have "wrong" but isn't the cause...
Ok so results of testing polarization effect with what I had here:
Matte page protector put on intact mostly cancels out polarization blackout. One layer of it regardless of the smooth inside or the textured outside facing out weakens blackout a little but not much.
Clear/Glossy page protector put on intact very slightly weakens blackout. One layer does nothing with either side facing out.
A "thermal laminating pouch (slightly milky clear plastic with outside gloss finish and inside rougher and a little tacky) put on intact cancels blackout effect almost entirely. One layer reduces blackout effect roughly 50% regardless of which side faces out. In any combination it makes things a bit shimmery in color the way I have seen several screen protectors do when they change the polarization on a phone or tablet. It gets rid of the blackout but things look a little psychedelic in a way with slight movements changing colors and background shade.
I feel too bad to risk testing on a painful device for any strain relief right now and risk a flare up that will make things worse for days or weeks, esp since I don't believe polarization is my problem anyway since all LCDs use it and I can use specific old CCFL TN and old IPD LED with old software without problems, and wear polarized sunglasses without problems. But it is interesting to see how materials can affect the polarization.
I couldn't make a picture showing the rgb sparkle effect from the matte protector that showed it accurately. It's very ugly and irritating and looks like the white areas are rgb glitter.