Do smartphones emit blue light?
Written by
Chen Jialiang
Reviewed by
Prof. William Dalton, Ph.D.Smartphones emit considerable blue light due to their LED screens, which can impact health. The emission maximum is about 460 nm and interferes with normal melatonin production. The effect of evening use without protective measures is a significant delay in the onset of sleep. Understanding this emission allows you to take protective measures against it.
Melatonin Disruption
- Peak emission at 460nm suppresses sleep hormone
- 30 minutes of evening use delays sleep by 15 minutes
- Cumulative effect worsens with nightly exposure
Eye Strain Mechanism
- High-energy wavelengths cause pupil constriction
- Reduces blinking rate during prolonged scrolling
- Leads to dry eyes and focus difficulties
Circadian Impact
- Resets internal clock timing each evening
- Delays natural sleepiness signals by hours
- Causes next-day fatigue and concentration issues
Phone settings, such as night mode, reduce the amount of emission, but they don't block melatonin-disrupting wavelengths entirely. Amber blue blocking glasses offer more reliable protection. I wear mine religiously after sunset, in particular while I am scrolling.
Children are at even greater risk from the blue light emitted by smartphones. Their eyes absorb much more high-energy light than those of adults. Set device-free periods before sleep. Physical barriers, such as glasses, rather than software ones, should be used. It is important to protect the developing visual systems properly.
To measure smartphone radiation, a special tool called a spectrum analyzer is required. Consumer lux meters can detect visible light but not certain wavelengths associated with blue light. Professional spectrometers highlight the issue even further by showing the problematic spike at 460nm. Manufacturers should display the emissions in the same format as sunscreen affecting sunlight, i.e., comparable to SPF.
Read the full article: 10 Best Blue Blocking Glasses Unveiled
