Circadian rhythm restoring blue blockers

A wearable device for viewing a real or virtual environment, comprising:

• one or more windows positioned to allow light from the real or virtual environment to propagate toward a position of a wearer's eyes;
• and
• a spectral filter that comprises a coating positioned on one or more sections of the one or more windows,
• wherein the spectral filter includes a multi-layer stack of dielectric material with alternate high and low indices of refraction such that a layer having a high index of refraction is positioned above or below a layer having a low index of reflection,
• wherein a number of the layers and a thickness of each layer are selected to provide designed transmission and blocking characteristics to block circadian-rhythm-disruptive spectra from passing through the spectral filter while providing viewability of the real or virtual environment by allowing light outside of the circadian-rhythm-disruptive spectra to pass through the spectral filter,
• wherein the designed transmission and blocking characteristics include three contiguous blocking regions at 365-400 nm, 455-495 nm, and 530-560 nm bands of wavelengths, and three contiguous transmission regions at 405-450 nm band of wavelengths with a tolerance range of ±5 nm, 497-528 nm band of wavelengths with a tolerance range of ±2 nm and 565-695 nm band of wavelengths with a tolerance range of ±5 nm, and
• wherein the spectral filter is configured to block 80-100% of spectral content in each of the contiguous blocking regions.