Blue-Light Filters in Eye Care: A State-of-the-Art Review.

Blue-light filters now span spectacle, contact and intraocular lenses, but the term encompasses technologies with markedly different spectral characteristics and intended outcomes. This state-of-the-art narrative review synthesises peer-reviewed evidence on optical performance, digital eye strain, glare, photostress, sleep and circadian physiology, retinal phototoxicity, macular health, reported adverse effects and commercial translation. Near-clear spectacle filters preserve high-contrast acuity in most studies, but randomised and systematic reviews show no clinically meaningful average reduction in short-term digital eye strain. Some products reduce blue-colour contrast, particularly under low-contrast or low-light conditions, and adverse-event reporting is sparse. Studies of evening filters are heterogeneous: substantial amber attenuation can alter circadian light exposure, yet several trials have found no objective sleep benefit. Conventional visual outcomes with blue-filtering intraocular lenses are broadly comparable with ultraviolet-only lenses, although some individual studies report small mesopic colour or contrast disadvantages; long-term macular protection remains unresolved. Research on contact lenses is limited, typically short-term and often manufacturer-associated, and focuses on glare, photostress, scatter and perceived brightness rather than long-term health outcomes. Taken together, the evidence should be interpreted by filter spectrum and intended outcome, rather than treating blue-light filtering as a single intervention.