Blue light: Is it worth blocking?

Blue light: Is it worth blocking?
Posted on 04/07/2020
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What is blue light?

Blue light can be found in anything from fluorescent lighting to LED computer screens, including the cell phones you use every day.

When our eyes are exposed to blue light, excitatory signals are sent to the brain. It’s essentially sending the message “Wake up and smell the coffee!”

Daylight consists of non-visible, harmful UV light, and visible “beneficial” light. Blue light is found where these two spectrums meet and is referred to as HEV light or high energy visible light (see image). Blue light has been found to be important for alertness, memory and cognitive function. As we shift to energy saving LED bulbs in the house and increase our screen time in the workplace and at school, eyes are becoming more stimulated than ever before.


Don’t our eyes filter out the harmful light?

When we are outdoors, the clear structures in our eyes are pretty good at filtering out harmful UV rays before they reach the retina. Blue light, however, is not well filtered. Why does this matter? Well, blue light is the highest energy wavelength of visible light allowed to reach the retina. The higher the energy, the more potential to be damaging to the retina.

Blue light and sleep:

Blue light from LED screens stimulates retinal cells resulting in a downregulation of melatonin. This can have a negative effect on our sleep cycle. Melatonin is a chemical that our body produces at night to help us get “sleepy”. In one study, when subjects were exposed to 6.5 hours of blue light vs green light, researchers found that blue light suppressed melatonin for about twice as long as green light did. There was also a shift in circadian rhythm equivalent to twice as many hours of exposure.

This is why screen time before bed can reduce the amount of restful sleep hours we get.

Blue light and macular degeneration risk:

Although studies have not found hours of screen time to be directly harmful to the retina, long term effects are largely unknown and children’s eyes may be more at risk since their eyes transmit much more blue light energy to the retina. In order to see the long term effects of blue light exposure, we will need to wait 50+ years for today’s youth to reach the age when retinal damage typically occurs.

What can you do?

  1. Use dim red lights for night lights.
  2. Avoid looking at bright screens beginning two to three hours before bed. Turn on your “night shift” or “blue light filter” mode on your cell phone so the screen shifts from blue to orange tones.
  3. If you do a lot of computer screen time wear blue-blocking glasses or use a screen protector that filters out blue wavelengths. See examples below.
  4. Eat a diet rich in antioxidants and carotenoids such as Lutein, found in dark leafy green vegetables.

Blue blocking screen protector:

Zagg VisionGuard with EyeSafe technology

Blue blocking lenses:

Bluetech lenses - block 100% UV and up to 60% harmful blue light
Essilor Eyezen computer lenses - block up to 20% of harmful blue light

Photochromic lenses:

Transitions XTRActive - blocks 100% UV, up to 34% of the harmful blue light indoors and 88% to 95% of harmful blue light outdoors
ZEISS PhotoFusion - blocks 100% UV, up to 20% (31% for Extra Grey) of harmful blue light indoors and up to 90% of harmful blue light outdoors

Blue blocking contact lenses:

Acuvue Oasys with Transitions - block 100% UV, up to 15% of harmful blue light indoors and 55% of harmful blue light outdoors

Blue blocking antireflective coatings:

Crizal Prevencia - blocks up to 20% of harmful blue light
DuraVision BlueProtect UV by ZEISS - blocks 100% UV and up to 15% of harmful blue light

Additional Resources:

Talia M. Mishkin, O.D

Millennium Eye Care

  • FREEHOLD - 500 W. Main St, Freehold, NJ 07728 Phone: 732.462.8707 Fax: 732.462.1296
  • EAST WINDSOR - 440 Route 130 South, East Windsor, NJ 08520 Phone: 609.448.3990 Fax: 609.448.4197
  • MARLBORO - 455 Route 9 South, Englishtown, NJ 07726 Phone: 732.591.2200 Fax: 732.591.6347
  • MONROE - 4 Research Way, Monroe, NJ 08831 Phone: 609.495.1000 Fax: 609.495.1005
  • BRICK - 515 Brick Blvd., Brick, NJ 08723 Phone: 732.920.3800 Fax: 732.920.5351
  • JACKSON - 2080 W. County Line Rd, Jackson, NJ 08527 Phone: 732.364.5123 Fax: 732.364.3865

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