Nox is a screen filter for macOS that applies spectral wavelength filtering to reduce discomfort from light sensitivity, with a focus on migraine-associated photosensitivity. Unlike general color temperature tools, Nox operates at the display driver level and includes presets targeting specific wavelength ranges linked to photosensitivity. ($5, one-time)
The app ships with 12 research-based filter presets. These include FL-41 tint emulation — a rose-tinted lens traditionally prescribed for migraine and blepharospasm — a 480nm blue notch filter, narrow-band green (520-540nm), and e-paper simulation. Each preset reflects documented research on wavelengths that activate the intrinsically photosensitive retinal ganglion cells responsible for light-triggered discomfort.
Users who want finer control can customize RGB channel levels, gamma, contrast, and color temperature between 2700K and 6500K, then save custom presets. A real-time melanopic suppression readout shows the percentage of melanopsin-activating light being blocked, providing direct feedback for adjusting filter intensity. Multi-display support applies filtering independently per monitor. Global keyboard shortcuts allow quick preset switching, and a built-in break timer provides reminders for screen time management.
Nox does not include automatic sunset/sunrise scheduling, which apps like f.lux and Night Shift provide. Filtering accuracy is also display-dependent since adjustments occur at the driver level; the app notes that spectral graphs shown in its interface are approximate.
System requirements: macOS 14 or later; compatible with Apple Silicon and Intel Macs.
Pricing: ($5, one-time lifetime license; 14-day free trial)
Limitations: No sunset/sunrise scheduling. Actual spectral filtering accuracy varies by display hardware. Not a medical device and does not diagnose or treat photosensitivity conditions. macOS 14 minimum excludes older systems.
Alternatives: f.lux (free) adjusts color temperature automatically based on time of day but lacks wavelength-specific presets. Night Shift (built into macOS) offers basic warm-tone shifting with scheduling. Vivid brightens display output but does not filter specific wavelengths.
Suitable for users with migraine, photosensitivity, or extended screen time discomfort who need more targeted wavelength filtering than standard color temperature tools provide.
