What is Blue Light?
Blue light’ is a naturally occurring wavelength of light found near the ‘pre-UV’ portion of the visible light spectrum (380-495nm). Historically, human exposure to blue light during daylight hours has been associated with positive benefits such as increased energy and wakefulness. However, as blue light emitting devices such as smartphone screens and overhead lighting command more and more time in front of our eyes, blue light exposure has begun to reach disruptive or even unhealthy levels for many people with modern lifestyles.
Damage to the Eyes
Mounting medical evidence suggests that prolonged exposure to blue light- like that emitted by a computer screen or smartphone- may permanently damage the eyes and contribute to both the formation of cataracts and to the destruction of cells in the center of the retina.
Because it is a high-energy wavelength, blue light is capable of causing damage when it strikes the retina. With age, the eye lenses naturally yellow, filtering out most blue light. This means that young people, particularly those under 25 years old, are most susceptible to the hazards of blue light exposure. However, older people are also at risk, since the blue light absorbed by their yellowed lenses can cause cataracts.
Blue light is closely tied to the body’s circadian rhythm, or ‘internal clock’, because it powerfully suppresses the body’s secretion of Melatonin, a hormone that regulates sleep and wakefulness. Though blue light is present in the sun’s rays during the day, it is less pronounced around dusk, which is why sunsets tend to appear red. The lack of blue light in the evening allows the body to produce melatonin freely, signaling that it is time to prepare for sleep. Exposure to blue light via electronic devices or office lighting after the sun has gone down can disrupt one’s circadian rhythm, making it harder to fall asleep or get a good night’s rest.
What can I do?
To protect the eyes and maintain a healthy sleep schedule, you should:
- Expose yourself to natural daylight
- Protect your eyes from UV rays using sunglasses
- Protect your eyes from excess artificial blue light using blue light-filtering glasses