Recently, while working in a French public school, I noticed something interesting and potentially useful for others who suffer from screen sensitivity.
There was an old desktop setup, running Windows 7 Education and connected to a CCFL monitor. Despite its age, the screen caused me instant eye strain and visual discomfort. I had assumed older hardware would be safer, but that wasn’t the case — likely due to temporal dithering still being active at the GPU level, even on these legacy machines.
However, in that same room, a long-throw Epson projector was used (a model from the early 2010s, most likely using a UHP discharge lamp, not LED). I could watch it for hours with no symptoms whatsoever. The projected image felt soft and natural. This difference was stark and consistent.
In another classroom, everything was nearly identical — same type of computer, same educational OS — but the projector was a short-throw model, probably LED-based or modulating light differently. I couldn’t stay more than a minute in the room without nausea, dizziness, and neck tension. The change in projector made a drastic difference.
I also found posts by someone using the Vivitek D554, a single-chip DLP projector with a 190W metal-halide (discharge) lamp, SVGA resolution (800x600), and no visible dithering. These older DLP models use a color wheel and micro-mirror array, displaying each color channel sequentially at very high frequency. They don’t rely on frame rate control (FRC) like modern LCD/OLED displays. This likely explains why some people with extreme sensitivity can tolerate them, whereas they cannot use even older LCD monitors.
So my current assumption is:
•Even legacy computers running Windows 7 can become suddenly unusable for sensitive users if a GPU driver update or a system-level patch silently enables temporal dithering. This might happen even with CCFL 8-bit monitors that used to be perfectly fine.
• Lamp-based DLP projectors (like Epson long-throw or Vivitek D554) are immune to dithering and PWM-related flicker, due to how their light is modulated and displayed,
• Short-throw projectors may introduce visual strain either because of LED light sources, different optical paths, or faster modulation profiles.