The eye is one the most complex organs in the human body..and perhaps the coolest in our opinion. This anatomy brief doesn’t do justice to the intricacies of the visual system, rather highlights the important aspects of how light enters our eye; providing a foundation of knowledge that will help you understand how light and your visual lifestyle can impact your health if not protected.
Light hits the CORNEA. The cornea is clear layer on the front of the eye responsible for bending the light rays (starts the focus process) before entering the eye.
Then the IRIS, that pretty colored part of your eye, controls the amount of light entering be changing the diameter of the PUPIL. Our pupils expand in dark environments to allow more light through and contract in bright environment. (*This is an important concept when lighting your work environment; check out our Top Tips for more information.) As we grow older, the pupil becomes smaller. In other words, children have larger pupils which allow more Blue Light into the eye.
The LENS is directly behind the pupil. Also referred to as the crystalline lens, this part of the eye does something called ‘accommodation’ which changes the shape of the lens to focus on objects at different distances. (*Don’t let your lens stay in one shape all day in the office, make sure to practice the 20/20/20 rule). When discussing Blue Light, it’s important to understand that our lens naturally changes color over time. As we grow older, the lens changes to a more yellow color, preventing shorter, damaging wavelengths of light from entering the eye. In other words, children’s lens lack the natural coloring to protect certain harmful light. (*starting to see the trend? Children are at higher risk, see more here)
The focused light travels through the gel substance area called the VITREOUS BODY to reach the RETINA. The retina is a light-sensitive layer of tissue where the light is converted to electronic signals. The very center of the retina is called the MACULA. Conquencidently it is this center part of the retina that is responsible for our central, pinpoint vision. Our peripheral vision comes from the area of the retina surrounding the macula. (*We get into the macula in more detail here)
Finally the OPTIC NERVE sends the electronic signals from the retina to the visual cortex of the brain, producing an image.
Chances are that you’ve experienced Digital Eye Strain, whether or not you’ve called it that. In fact, you may be experiencing some of the symptoms as you read these very words. According to the Mayo Clinic, the symptoms of DES are these all too common feelings: sore, tired, burning, itchy, watery, or dry eyes; blurred or double vision; headaches; sore neck, shoulders, or back; an increased sensitivity to light; difficulty concentrating; and/or the feeling that you can’t keep your eyes open.
Because blue light exists naturally in abundance from the sun, our biology is primed to interpret blue light as daytime– time to be awake! This mechanism works through, you guessed it, our eyes. The melanopsin receptor in our eyes send a signal to the suprachiasmatic nucleus, which in turn activates or deactivates the pineal gland, which produces melatonin.