Nox vs Iris:
which is right for light sensitivity?

The fundamental difference

Why does this matter? Iris's blue light reduction, like most filters in this category, works on a broad schedule, shifting color temperature and brightness gradually from day to night. That helps with general eye strain and circadian rhythm. Research by Noseda et al. (2016) found that migraine photophobia is driven specifically by intrinsically photosensitive retinal ganglion cells (ipRGCs) that peak at 480nm, and that narrow-band green light around 530nm is the one wavelength shown not to worsen migraine pain. A broad schedule reduces some of that light along the way, without targeting it.

Nox's presets are built directly from that research. The FL-41 clinical tint is the same profile shown in clinical trials to reduce migraine attacks by 74%, paired with a notch filter centered on 480nm and a narrow-band green pass near 530nm. Each preset is documented on our research page with the underlying studies linked. Iris's own marketing focuses on general sleep and eye-strain guidance rather than migraine-specific citations, which fits its broader intended audience. For more on the mechanism, see how FL-41 tint applies to screens.

Side-by-side comparison

When Iris is the right choice

If you move between Windows, macOS, and Linux, or want filtering on your phone too, Iris covers that ground. Nox does not; it's Mac only. Iris also bundles more into one app, including break and exercise reminders, ambient brightness features, and an extensive settings surface for people who want to tune everything by hand.

Iris also has a genuinely free tier (Iris mini and Iris micro) that covers its core blue light and brightness features at no cost. If your goal is general eye strain and sleep support rather than migraine-specific filtering, and you want one tool across every device you own, Iris is a reasonable choice.

When you need Nox instead

If you're on a Mac and dealing with migraine or photophobia specifically, not just general eye strain, you need wavelength-level precision rather than a broad day-and-night schedule. Nox's presets target the 480nm melanopsin peak directly, with a real-time metric showing how much of that light each preset removes, plus dimming that goes below your display's hardware minimum for the rooms and flare-ups where even the lowest backlight setting still hurts. A global keyboard shortcut toggles the whole filter instantly, which matters when light sensitivity flares up and you don't have time to dig through a settings menu.

The pricing is closer than you might expect, with one difference in structure. As of July 2026, Iris's paid version is a $15 one-time purchase that covers one major version, alongside its free tiers and a subscription option. Nox is $5 once, and the license includes all future updates rather than one version. Both are cheap; the difference is that Nox is built by one developer around one purpose, so the $5 buys the whole app, permanently. For a full setup walkthrough, see best screen settings for migraines.