Barakta tried a couple (on a desktop monitor), because she was stuck with a choice between running the screen at full brightness so the backlight didn't flicker, or dimming it down for 200Hz strobe-o-vision at a reasonable intensity - both of which were migraine triggers.
One was a clip-on thing that didn't fit very well, and caused unwanted reflections.
Another was a sheet that stuck to the surface of the display electrostatically. It was basically impossible to do this without introducing some trace of dust between the layers (think applying a screen protector to a mobile device, but much bigger and with gravity against you), and it didn't quite reach to the edges, resulting in a bright line that had to be covered with insulating tape, at loss of some pixels.
I can't imagine these things being anything other than a massive pain on a laptop.
Eventually we tracked down a model of monitor that had a non-flickery backlight and a matte screen surface (to minimise reflections). This is surprisingly hard to find, because all the high-end stuff has shiny screens to improve the sharpness (in perfectly lit rooms), and it meant she had to give up her preferred 2x 5:4 display arrangement. (She's now got a 4:5[1] and a 16:10, which is about the same area in a less useful configuration.)
[1] An old Dell 5:4 thing mounted on its side for about the same height.
