Deeply tinted amber lenses worn in the two to three hours before bed shift sleep earlier and improve how people rate their own sleep, most clearly in those who already sleep badly. Gains measured by devices are smaller and less consistent. Screen-comfort and eye-protection claims are not supported. All-day wear removes light the body needs for alertness. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Evening melanopic EDI at eye level | Under 10 lux in the 3 hours before bed | Confirms lenses plus room lighting reach the target dose |
| Morning outdoor light exposure | At least 10 minutes above 10,000 lux within 60 minutes of waking; 30 minutes when overcast | Guards against the main harm, which is cutting daytime blue light |
| Sleep onset latency | Under 20 minutes | The endpoint that moved most in blue-blocking trials |
| Total sleep time | 7-9 hours | Shows whether earlier sleep onset actually yields more sleep |
| Sleep efficiency | Above 85% | Separates more time in bed from better sleep |
| PSQI global score | 5 or below | Validated self-report scale that showed the largest effects in trials |
| ISI total score | 7 or below | Grades insomnia severity when insomnia is the reason for use |
| Salivary dim-light melatonin onset (DLMO) | At least 2 hours before habitual bedtime | Times the internal clock directly rather than by proxy |
Cadence: Two weeks of unfiltered baseline recording, then the sleep record and both scores repeated at 2 weeks, 6 weeks, then every 6 months; the light audit is repeated whenever lamps, lenses, or living space change.