Every ray of light that we see is made up of a number of different colors, each a different wavelength and frequency. Sunlight, for example, is a spectrum consisting of violet, indigo/purple, blue, green, yellow, orange, and red light, in that order. Red colored rays have the longest wavelength and lowest energy, whereas colors on the opposite end of the spectrum have short wavelengths and high energies.
While the anterior structures (the lens and cornea) of an average human eye have evolved to block out the most extreme end of the spectrum (UV light) and keep them from reaching the retina, they let nearly all visible blue light pass through them, which can be extremely dangerous in the long run.
Common sources of blue light
- Sunlight
- Fluorescent lights (like tube lights)
- Compact fluorescent lights (CFL bulbs and fixtures)
- Most screens, be it computer monitors, televisions, smart phones, and tablets
Effects of blue light
- Digital Eye Strain – As light of shorter wavelengths have higher energy, they bounce and scatter more easily. This can lead to “visual noise” of sorts, that strains the eye greatly and leads to general headaches and eye aches. This is also called computer vision syndrome.
- General fatigue – As our eyes and bodies have evolved to absorb most blue light during the daytime, from the sun, long exposure to it from other sources like your computers or your phones can have greatly detrimental effects on your natural body clock. This can lead to restless or poor sleep, and general fatigue during waking hours.
- Dry eyes – Long sessions of using screens can lead to dry eyes.
- Damage to retina – Blue light exposure has also been linked to retina damage, which can lead to dangerous and incurable conditions like macular degeneration, one of the leading causes of vision loss.
How to protect against blue light
- Reduce screen time – The lesser the time you spend exposing yourself to blue light, the lesser its effects will be.
- 20-20-20 rule – After looking at any digital screen for 20 minutes, look away at any object at least 20 feet away, for 20 seconds.
- Special blue-light filter glasses – Over the past few years, it has become common practice to use special yellow-tinted glasses which can block out most of the dangerous blue light rays.
- IOLs (Intraocular lenses) – This is perhaps the most extreme way to protect yourself from dangerous blue light rays. IOLs are thin, flexible, and clear plastic lenses that are generally used to replace the natural lens of a human eye after it gets damaged, or cloudy due to cataract. Commonly, IOLs keep out nearly all UV light, just like a natural lens, but some special types of IOLs can protect from blue light as well.
- Turn on Eye-Care mode on your device – Most devices nowadays come with a night / eye-care mode that make the screen warmer and claim to nullify blue-light damage. While this isn’t the ideal solution, if you can’t avoid your screen and you don’t have access to blue-light filter glasses, this may offer some level of protection.
