Blue light and sleep
Why evening light can push sleep later.
Blue-rich evening light can suppress melatonin and push the body clock—and sleep—later. Timing, intensity and duration all matter.
The body clock
Your eyes do more than see.
Light-sensitive cells in the retina help set the body’s internal clock. Human circadian photoreception is especially sensitive to short-wavelength light: melanopsin peaks at approximately 479–480 nm, while the standardised melanopic action spectrum at the eye peaks at approximately 490 nm.
In daylight, that signal helps support alertness. In the evening, a strong blue-rich signal can delay the biological transition towards night.
Lens design
Engineered for the
Melanopic Sensitivity Zone
The deep-amber colour is a visible consequence of the filtration, not a styling choice. A strong amber cast is the expected viewing experience: screens and text remain usable, but colours look distinctly warmer.
What studies measured
Less evening melanopic light, different night-time signals.
Evening displays
In a controlled study of 72 healthy men, more melanopic light reaching the eye from evening displays meant greater melatonin suppression, later melatonin onset and longer sleep-onset times.
Schöllhorn et al., 2023 · Communications Biology
Light-emitting reading
In a laboratory crossover study of 12 adults, four hours of evening e-reader use delayed the body clock and made sleep take longer compared with reading a printed book.
Chang et al., 2015 · PNAS
These studies investigated evening light and sleep mechanisms generally. They did not test SleepSpec.