On the heels of Dr. Fortenbacher’s comprehensive post about COVID-19 related excessive screen time, here are some insights from Professor Amanda Ellison, a physiologist and neuroscientist at Durham University. Professor Ellison had written a pithy and delightful book about a painful subject that touches all of us, namely headaches.
The book opens as follows: “We’ve all had that uh-oh feeling. Something doesn’t quite feel right. There’s a tightness, a fogginess, a malaise, a pain. Thirty minutes later we might use other words: splitting, pounding, banging. Now it’s a headaches. This happened to me recently. I was late for a meeting and couldn’t find my glasses … It doesn’t make much of a different to my everyday life since my brain compensates really well. However, if I am tired and working on a computer, my brain doesn’t have to work so hard if I have a corrective lens.”
Midway through the book, Professor Ellison adds: “I am also hitting that point in my life where my eye muscles don’t work as well as they used to and so I suffer from eye strain a fair amount, another cause of tension headache.”
The inside story of headaches could be an even easier read with a diagram or two, but despite the continuous text without much of a break in each chapter, Professor Ellison paints a vivid picture of why the trigeminal nerve plays such a large role in referred pain in and around the eyes. The fifth cranial nerve (5) is the largest nerve above the level of the neck. It keeps close company with its numerical neighbors dedicated to vision and eye muscle control, cranial nerves 2, 3, 4, and 6. What makes cranial nerve 5 so large is that it has three divisions, one branch that goes primarily to the facial muscles and jaw (mandibular); one to the sinus area (maxillary) and one to the eyes and surrounding area (ophthalmic).
What isn’t widely recognized, and what Professor Allison does a really good job of pointing out, is that stress plays a tremendous role in inflammation that agitates the nerve endings. This results in referred pain that is registered in and around the eyes. She notes that anything one does to alleviate stress has a beneficial effect on reducing inflammation, and thereby referred pain or discomfort involving the eyes. This encompasses a wide range of physical factors, from adequate hydration to proper posture to appropriate lenses, that impacts performance through the visual system.
Movement and physiotherapy also plays a role in reducing referred pain in and around the eyes. That is why prolonged sedentary periods of time at the computer contributes to asthenopia; or perhaps what might be better termed “ass-then-opia”. Happy Thanksgiving, all!