Thank you for joining the Huberman Lab Neural Network — a once-a-month newsletter with science and science-related tools for everyday life. This newsletter aims to provide you with actionable information in a condensed form.

In Episode #24, I discuss the science of vision and how your eyes convert light energy (photons) into signals the brain can use to perceive images and to control hormone and neurotransmitter release in the brain and body. Because healthy, clear vision is important to everyday well-being and sense of vitality, this newsletter explains key behavioral and other tools to help improve your vision and eye health and reduce age-related vision decline.

Daily Practices for Eye Health

Throughout the day, your eyes have to adjust in many ways in order for you to maintain a crisp, sharp image of the world around you. The lens of the eye is “relaxed” when looking off in the distance, such as when looking towards the horizon. To focus on closer objects, the eye adjusts by thickening the lens to bring these objects into sharp view. When you spend many hours focused on close-up objects (computers, screens, phones), the eye muscles and nerves that control them are working hard. Over time, viewing objects up close for most of the day changes the length of the eyeball. These changes make quickly focusing on different distances — especially far-off ones — more challenging and can exacerbate myopia (nearsightedness).

  • To maintain healthy eyes, focus on periodically letting your eyes relaxthroughout the day. If you do a lot of up-close work (computer, reading, etc.), aim for more balance of near and far viewing, and allow your eyes to view far-off distances multiple times throughout the day. Try taking calls or joining a meeting while sitting outside or while walking, or look out a window to the furthest location you can. You don’t need to fixate on one visual location; rather, viewing to multiple distances far away (beyond 3 feet out to infinity) is key.
  • Frequently focusing on close-up objects (e.g., computers) can predispose you to tension headaches too. In fact, for every 30-60 minutes of up-close work, allow all your face muscles to relax (including the jaw muscles) for 1-5 minutes or so while viewing things further out in the distance. Even more time viewing things in the distance in this relaxed manner would be better, but most people are simply not able to divorce themselves for more than 1-5 minutes per every waking hour from screens viewed up close. Still, do what you can.
  • Headaches and fatigue due to up-close viewing can also be mitigated by “optic flow.” Get outside for a walk, run or bike ride. Don’t read on your phone for more than a glance or so while doing these activities, of course! The panoramic vision and optic flow induced by self-generated movement can reduce anxiety and improve mood. Alas, while exercise is good, optic flow is not the same on a stationary bike or treadmill. Get outside and move as best and as often as you safely can.

The incidence of myopia is rising around the world, particularly in kids and young adults, who spend more time indoors. Wu et al. found that kids who get more than two hours of sunlight daily have lower incidence of myopia. Much of this effect is probably due to far viewing, and yet we also know that sunlight activates specific neurons in the eye called intrinsically photosensitive retinal ganglion cells that indirectly control blood flow and support the ciliary body (which controls the aperture of the eye) to improve eye health. Those mechanisms may explain why getting outside for 2+ hours/day of sunlight can protect from and possibly help reverse myopia.

  • Try to get outside for 2+ hours a day, preferably without sunglasses — unless of course your eyes are very sensitive — and NEVER stare at the sun. A brimmed hat is fine if you need it; people vary in their sensitivity to brightness. If you must, take your work outside to reach that 2 hours. You can still focus on a computer, studying or working outside, as the ambient sunlight will aid eye health and contribute positively to overall health. Remember to take visual breaks throughout the day to do far viewing, even if working outside.