The eye - a blue light sensor (Melanopsin)
In terms of eye anatomy most of us are more familiar with the “rod and cone cells” which help us see, But what you probably haven't heard of is something called IPRGC’s (Intrinsically photosensitive retinal ganglion cells).
One of these IPRGCs is called MELANOPSIN, and it plays a major role as our central BLUE LIGHT SENSOR. Most of you have heard me incessantly talk about the benefits of red light, but blue light also has its associated. The complicated issue with blue light is that getting too much of it at the wrong time makes it toxic. Melanopsin plays a central role in regulating our circadian rhythm and therefore hormonal balance and cognitive function.
This may make you think “GREAT! Bring on the blue light”, however, the majority of us receive blue light in excessive amounts. How do you know you're blue light toxic?
Do you look at your phone past sunset?
Do you use artificial lights at night?
Watch TV, work on the computer in the evening?
Congrats! you're qualified for these adverse health effects - Poor eyesight, inflammation, insulin resistance, poor sleep, damaged mitochondrial DNAHere are a few ways blue light is harmful for our eyes.
1. Too much blue light will destroy melanopsin which makes your eyes less responsive to light distorting pupillary responses.
2. Blue light destroys your mitochondrial ability to produce ATP by destroying mitochondrial DNA
3. Blue light decreases the amount of blood flow to the eye, decreasing the amount of available nutrients and removal of toxins
4. Blue light also oxidizes DHA within your eye. Oxidation creates harmful free radicals which go on to inflict damage to adjacent structures.
These blue light sensors take a lot of light to be stimulated. Opening your eyes in a dimly lit room will do little to completely throw off your circadian rhythm. They will also not respond to warm, orange, and red light.
It's important to note here that these blue light sensors communicate with an area of the brain called the suprachiasmatic nucleus (SCN). This SCN, which is a network of 20,000 cells is connected to the hypothalamus which houses commands for hunger, sleep, stress response, and satiety. It is also indirectly connected to the pituitary gland which produces growth hormone, and stress hormones for the adrenal glands, thyroid gland, and gonads for reproductive hormones. Lastly, it is also connected to the pineal gland which produces the sleep hormone melatonin.
Melanopsin works together with he Suprachiasmatic Nucleus (SCN)- and therefore helps regulate every growth and metabolic function in your body. This master clock inside our brain located right behind our eyes and plays an important role in regulating all the other clocks within the body and keeps everything running on schedule.
This clock, which is a network of 20,000 cells is connected to the hypothalamus which houses commands for hunger, sleep, stress response, and satiety. It is also indirectly connected to the pituitary gland which produces growth hormone, and stress hormones for the adrenal glands, thyroid gland, and gonads for reproductive hormones.
Three scientists from the 2017 won the nobel prize for discovering the PER gene, or peripheral gene that is located within every cell and it pays attention to the SCN. If the SCN is misinformed, it signals every cell in your body about changes in your environment.In short: It is the link between LIGHT and TIMING.These findings help us understand how light affects our health. Today's modern lifestyle of indoor living, bright LED screens, and lights on at night activates our melanopsin sensors at the wrong times of the day. This is a problem as it disrupts our circadian rhythm, reduces melatonin, and leaves us groggy the next day due to poor quality of sleep.
The truth is, we cannot escape our 6 million years of biological evolution in a matter of approximately 60 years since the evolution of the light bulb. From halogen bulbs to the “energy saving” compact fluorescent light. We have confused our SCN, our brain, our physiology, and ultimately hindered our health.