Many of us spend the majority of our time indoors, and a large percentage of this time is spent looking at screens which are within one to two feet from our faces. Much has been written about the biomechanical effects of staring at screens. Articles on forward head posture and “text neck” abound, and at this point there is no doubt that staring at a computer or cell phone with your head forward causes tightness at the back of the neck, along with many other undesirable effects. Today, however, I am interested in exploring a different aspect of constantly staring at screens: the chronic eye fatigue caused by fixating on one (near) visual object and the ripple effects felt throughout the body.
Part of the problem we face in the digital age is that there is a difference in visual demand when one is viewing the display on the computer screen compared to reading a printed text. An image which is produced on the screen is made up of thousands of tiny pixels which collectively form the image, making it harder for the eye to latch onto it. In order to focus, the eyes must readjust every few minutes. This constant readjustment over time is thought to cause repetitive stress to the ocular muscles, leading to Computer Vision Syndrome. The contrast of the word to the background, the glare of the computer screen and the reflection from the glass all contribute to increased visual demand. The longer we expose our eyes to this increase in visual demand, the more tension our eyes will experience and the more likely the tension is to spread.
Eye movements play a role in muscle tone, especially for the suboccipitals, a set of four pairs of muscles that connect the cranium to the first two cervical vertebrae.
You can easily feel the connection if you place your hands on either side of the head with your thumbs just below the edge of the skull. Slowly let your thumbs work through the outer muscle layers so that you have contact with deep muscles. Close your eyes. Now try to move the eyes from side to side, and up and down without moving the head. You should be able to feel small changes in the muscle tone. Although the head and neck are kept still, the suboccipital muscles respond to eye movements. They are so fundamentally connected that any eye movement will produce a change in these muscles. This, in turn, will affect the spinal muscles as they take movement cues from the suboccipitals. In other words, chronic eye tension from sitting and staring at a screen will produce tension in the back of your head, down your spine and even into your pelvis, compounding the pain and stiffness caused by the biomechanics of the sitting posture itself.
In addition to pain and stiffness, pathological tension in both eye and neck muscles commonly causes headaches. Fatigued eye muscles can constrict blood vessels in and behind the eyes. The resulting vessel spasms are believed to be a major cause of ocular headaches, along with changes in the optic nerve. When the neck becomes tight, the occipital nerve can easily become compressed in the space between the first two vertebrae, referring pain to multiple muscles in the neck and head. There are also small myofascial strands, called myo-dural bridges, that connect the muscles in the back of the cranium to the dura mater, the membrane surrounding the brain and spinal cord. Increased tension in these muscles pulls on the dura mater, making the headache worse.
“Reflex control of the spine and posture: a review of the literature from a chiropractic perspective”, Mark W Morningstar, Burl R Pettibon, Heidi Schlappi, Mark Schlappi, and Trevor V Ireland, Chiropractic & Osteopathy, August 2005