Ultra Violet (UV) wavelengths can have some dramatic effects on your eyes and skin, causing things like cataracts and skin cancer, but did you know that the high energy waves in the visible light spectrum can also cause issues? Blue light deeply penetrates the eye and can cause damage to the retina over time, however this is minimal for most of us and takes many years. This is not what doctors are most concerned with, rather it’s the suppression of melatonin production (the sleep hormone) that causes the most disruption: by reducing our quantity and restfulness of sleep.
Even at low intensity, blue light stimulation significantly suppresses melatonin; this chemical that helps you feel ready to sleep. This effect continues a full hour after we stop being exposed to the light. This means if we use computers, TVs, tablets or smart phone until we want to sleep, our bodies will have a hard to time falling asleep and getting restful sleep. We also tend to stay awake longer due to the increased alertness from the light’s stimulating effect on the brain. These wavelengths (380-450µm) stimulate your brain to stay alert better than caffeine!
This effect is more pronounced in children and adolescents. An AMA report shows that reducing screen time before bed improves quality of sleep (defined as more time spent in REM sleep) as well as helps the students focus better in school the next day. The doctors at Eyecare Associates recommend that if you are unable to reduce time spent with devices, that you consider glasses that block most of blue light for the 2-3 hours before bedtime you are using your device.
Blue light is not all bad though. In fact, it helps us wake up and stay alert throughout the day using the same process. It also improves our mood and enhances our ability to focus on tasks.
Blue light is emitted from artificial light sources like energy efficient lighting (especially cool white LEDs), and electronics (LCD’s like phones, monitors, as well as TVs) but the major source during the day is the sun. If you work in a dim room regularly, like your eye doctor, it’s helpful to go outside to increase your alertness through some sun exposure, even if just for a few minutes.
So how do we manage these wavelengths in our life to our advantage? Since exposure during the day is beneficial, we only need to worry about prolonged screen time (2+ hours at a time) or evening exposure.
Here are some things to try to reduce exposure:
Bottom line, if you’re using devices before you go to bed, you are reducing your quality of sleep and reducing your focusing ability the next day. If you’d like more information read our blog post on blue light, which has additional information and links to other articles.
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