When I was a child, my mother often told me to look into the distance whenever I had the chance, whether we were at home, in the car or outdoors. When I asked her why, she said it was good for my eyes, but without being able to give me a rational or accurate explanation. I imagine she’d had to listen to the same thing from her parents, who must have heard it from their parents before that, and so on. Some kind of indisputable knowledge, passed down from generation to generation. When thinking about it again recently as part of my research on the benefits of views, I looked for a scientific justification for this ancient rule.
The Eye Accommodation Process
The human eye has the ability to accommodate in order to see at different distances. This natural ‘fine tuning’ of images so they always take shape on the retina – a condition of being able to see an object clearly – is facilitated by a change in the curvature of the lens, caused by a contraction of the ciliary muscles. This action is also accompanied by a shrinking of the pupil so as to increase our depth of field.
For a normal eye, when relaxed, light coming from objects far away focuses naturally on the retina. In other words, the eye is capable of seeing distant objects clearly without any effort. On the other hand, it has to go through a process of accommodation to be able to clearly see nearby objects, to read and to write. Strenuous accommodation of the eye causes symptoms of visual fatigue such as eye pain and even migraines1. Looking into the distance therefore means the eye no longer needs to accommodate and can relax the contracting pupil and ciliary muscles.
Diagram of the eye when relaxed (top) and during accommodation (bottom) (Source: guide-vue.fr)
The Importance of Eye Movements for Eye Health
In the recent publication by Lisa Heschong2 on daylight, vision and views, we see (again) just how much more complex and sophisticated an organ the eye is compared with what we might remember from high school biology. The eye and the retina are among the most demanding elements of the entire human body when it comes to energy use. The process of phototransduction3, for example, meaning the conversion of light signals into electrical signals that can then be processed by the nervous system, involves a succession of chemical reactions that require a huge and stable input of energy. The act of keeping our eyes moving helps to pump more blood toward the eye muscles and surrounding tissues, thus providing the energy required. The movements of the eyeball and our eyelids (when we blink) also help keep our eyes properly hydrated.
The 20-20-20 Rule
When experiencing visual fatigue caused by prolonged exposure to screens, also known as computer vision syndrome, it is often recommended that you look at an object 20 feet away for 20 seconds every 20 minutes. This is the 20-20-20 rule, as popularized by Dr. Jeff Anshell4. There are numerous articles online that discuss this rule but without putting forward any mechanisms or scientific proof to validate it5. However, it seems to be a direct application of our knowledge of the phenomena described above. While working at a screen, our eyes are effectively focused on an object that’s close up, i.e. the screen, which leads to constant effort of accommodation and limited eye movement (for example, we blink two to three times less).
Taking regular breaks to look at something far away is recommended in order to combat visual fatigue (Source: optometrytimes.com)
An Equally Psychological Impact
According to the theory of biophilia, distant views also promote positive emotions and reduce stress. This reaction may result from the fact that we’re predisposed to react positively to natural environments, having been conditioned by the survival of our ancestors. Looking into the distance was effectively a means of keeping a lookout for threats and spotting shelter and food. There’s no correlation with vision, but you can see that the general interest in looking into the distance could well originate in part from this psychological effect.
The Importance of Views of the Outside from our Buildings
These days, we spend 90% of our time inside buildings. The jobs we do today require us to focus our attention for many hours on a precise task. Working at a screen has also become widely popular, contributing to the increasing risk of eye fatigue. How can we put the 20-20-20 rule into practice and maintain our visual health? There are apps that set off alerts at predefined intervals to remind us to take regular eye breaks. Access to windows with unobstructed views also provides beneficial motivation to divert our gaze and relax our eyes and our minds. Furthermore, views that are interesting and pleasant to look at are likely to induce greater eye movement6 and thus keep our eyes properly hydrated. Such views also guarantee good exposure to natural light, which we lack these days more than ever.
- Lighting and vision [Research report] INRS scientific and technical notes, R. Floru, 1996
- Visual Delight in Architecture: Daylight, Vision, and View, Lisa Heschong, 2021
- Clinical Anatomy and Physiology of the Visual System (Third Edition), Lee Ann Remington, 2012
- View preferences in urban environments, A. Batool et al., 2020