What it is
A full-screen visual overlay that reduces the brightness, contrast, and visual noise of the page underneath. Designed for people who experience visual snow, light sensitivity, or sensory overload from bright screens. The standalone version works as a tab you keep open behind your work · or you can invoke it over the current tab via a browser extension hand-off.
How to use
- Open the page.
- Click the Shield button to activate the overlay.
- Use the Intensity slider to adjust how dark the wash is. Start at ~40% and nudge up or down.
- Optional: toggle Reduced Motion to dampen any animations or auto-playing content on the underlying page.
- Switch to your work tab. The shield tab sits behind it, toning down the overall screen brightness through the browser window.
Why it helps
Visual snow and light sensitivity can make standard screen brightness feel aggressive, even at low device settings. This tool adds a controllable dark wash on top of everything, independent of OS brightness controls. For some users, reducing contrast and adding a subtle tint is more effective than simply dimming.
Full-page vs extension
- Standalone page: Open the tool in its own tab. Keep it behind your work tab. The browser window itself becomes the "filter." Works on any device with a browser.
- Browser extension (future): A one-click button that applies the overlay directly to the current tab, without needing a second tab open. Hand-off from the standalone page.
Safety notes
- Not a medical device. This is a comfort tool, not a treatment. If visual snow is new, severe, or worsening, see an optometrist or neurologist.
- Motion damping is passive. The reduced-motion toggle relies on the underlying site respecting prefers-reduced-motion. It cannot force-stop auto-playing video or GIFs on sites that ignore the preference.
- Extension hand-off is optional. The standalone page works without installing anything.
Technical notes
- Pure CSS + JavaScript overlay. No WebGL, no canvas, no heavy rendering.
- No tracking. No analytics. No cookies.
- Intensity and reduced-motion preference saved to localStorage.
- Works on mobile browsers but is most effective on desktop where multi-tab windowing is easier.