What is it?

Blue light is the short wavelength light of the visible light spectrum that makes up approximately 1/3 of all visible light. Blue light is generally defined as visible light ranging from 380-500 nanometers. Our main source of blue light is sunlight, however the number of indoor sources, being digital devices, is on the rise. Even though our eyes are good at blocking UV rays from reaching the retina, they are not very good at blocking out blue light. The effect of this exposure is cumulative and will vary depending on the total number of exposure hours.

Image Source: Seiko Vision
Is blue light harmful?

It is now believed that absorption of blue light over time is a contributing factor to aging, cataract formation, and damage to light sensitive retinal cells. New research has found that blue light from digital devices can trigger a process that causes photoreceptor cell damage. These changes resemble those of age-related macular degeneration, an incurable eye disease that can lead to permanent vision loss.

Blue light is also important in the regulation of our circadian rhythm, the body’s natural sleep/wake cycle. Exposure to too much blue light at night has been shown to suppress melatonin production, sleepiness, and morning alertness. This may lead to poor sleep quality, difficulty falling asleep, and daytime fatigue.

Who is it affecting?

Research conducted by the Alberta Association of Optometrists indicates 28% of parents say their child experiences symptoms during or after using digital devices. Another survey found adult Albertans spend an average of 10.5 hours using digital devices every day. More than 70% reported experiencing symptoms including headaches, blurred vision, and light sensitivity as a result of using a digital device.

How can I prevent it?

The effects of blue light may be minimized by:

  • Purchasing computer glasses or glasses with a blue-light filter
  • Purchasing sunglasses that can filter out both UV and blue light outside
  • Avoiding bright screens 2-3 hours before bed time
  • Avoiding cellphone or tablet use in the dark
  • Seeking some outdoor light exposure in the early hours of the day
  • Limiting screen time → no more than two hours per day for children aged 5-18, one hour per day for children 2-5, and avoiding it completely for children under 2 years of age