By Shaul Lent OTR/L, MA, CEAS
Lead Ergonomic Specialist
Your eyes are brimming with strain. After sitting in front of the computer for the entire workday – looking at that screen non-stop for eight hours – your eyes seem to be burning.
In this two-part article, I explain steps that you can immediately take to protect your eyes, without having to resort to special light installations, glasses, or hiring an ergonomic consultant. While these more costly adjustments could be necessary, we first recommend taking these inexpensive steps to reduce eyestrain.
In this article, we charge ourselves with two objectives: 1) to explain why our eyes feel strained after looking at the computer for long periods 2) to provide five simple solutions to immediately implement in our daily computer tasks. Part I of this post deals with the first objective, explaining why using the computer can cause eyestrain. Part II deals with finding solutions to this problem.
PART I: Why Eyestrain?
In order to understand why we develop headaches and eyestrain after looking at the computer, we first must look at the normal processes of the eye. Two terms, the resting point of accommodation and the resting point of vergence, must be defined.
The Resting Point of Accommodation
Our eyes adjust to look at objects at different distances. Eyes accommodate and readjust when viewing items far away and accommodate again when looking at an object close by. In a completely dark room, however, where our eyes are not staring at anything and do not need to adjust for distance, our eyes remain in the most relaxed, neutral position. This relaxed position is called the resting point of accommodation.
Most people prefer staying at the resting point of accommodation. This is the most relaxed position placing the least amount of stress on the eyes. Depending on a variety of factors including an individual’s eye anatomy and age, in order to achieve the resting point of accommodation, you should sit, on average, about 30-40 inches from an object.
Resting point of Vergence
In addition to accommodating to various distances, our eyes can converge or look inward towards our nose to allow both eyes to see an item at the same place. The ability to converge on a single object prevents each eye from looking at an item separately, in turn preventing “double vision.”
Just like the resting point of accommodation, our eyes prefer to converge in a most relaxed position. When there is nothing to look at, the eye converges and remains in the most relaxed position called the resting point of vergence. The resting point of vergence is achieved when looking at an item about 45 inches away. However, when gazing downward at about a 30 degrees angle, the resting point of vergence can be achieved at a shorter distance, about 35 inches.
What does this mean for computer users?
For a person sitting too close to the computer screen and away from this resting point of vergence and accommodation, the muscles of the eye become strained viewing the screen at a close distance. This can result in increased eyestrain and headaches. In addition to moving away from the resting point of vergence and accommodation, eyestrain can be the result of surrounding light or screen brightness, either being too dim or too bright. People will often need to squint to read words on a screen where the surrounding area or the brightness of the screen itself is too bright. Avoiding glare and squinting, trying to read an article in bright light, contributes to eye fatigue and strain.
PART II: How Can We Avoid eyestrain?
The first course of action is positioning the computer at an appropriate distance. We want to position the monitor at a distance that is not too far to diminish our ability to read yet not too close where it compromises our resting point of accommodation and vergence. In general, we advise placing the monitor about an arm’s length away from the user. The computer should be placed right in front of the user with the top of the computer at eye level.
We recommend, also, adjusting the monitor slightly so that the top of the computer is farther away from the bottom (rotating the top of the monitor away from the user). This allows for a downward gaze, giving us the ability to remain more in our resting point of vergence. Looking slightly downwards, we can have the screen at a closer distance and still have the ability to view and read images with maximal acuity.
2) Word Font
Another way to avoid eyestrain and headaches is to increase the font size or zooming in slightly to easily read information on the computer screen. Squinting to view small type fonts place unnecessary stress on the eyes and promote poor back posture. Most importantly for people with eye problems, reading small print forces the user to view items closer, compromising our resting point of accommodation and vergence.
3) Avoiding Glare
Another suggestion that we make to decrease eyestrain and headaches is to reduce excessive bright light either from outdoor sunlight or intense indoor lighting. An office setting can often be intensely bright, causing unnecessary glare on the screen. This might mean removing one of the bulbs from a light fixture or simply positioning the computer away from a light source. We understand that many employees do not have control over how much light is present in an office setting or where their desk is stationed, however explaining to a human resource administrator or a supervisor about how glare promotes discomfort or effects productivity might give you the ability to make the necessary change. These changes might assist not only the individual but also the entire office. These suggestions include:
- Removing the middle bulb of a four bulb light fixture
- Closing the drapes, shades, or blinds, especially those that are directly in front or behind a computer.
- Position the monitor so that windows are to the side (perpendicular to the screen), instead of in front or behind the computer.
4) Neutralizing Screen Brightness
One of the easiest and most effective ways to avoid eyestrain is to adjust the brightness on the monitor. The brightness of the monitor should be the same as the brightness of the surrounding area. To test this, look at a white background on the monitor (can be this page). If the screen looks like a light source and is brighter than the surrounding area, the screen is too bright. If the screen seems dark and dull, you should increase the brightness.
Another recommendation that can prevent eyestrain is called the 20:20:20 rule. Recommended by many ophthalmologists and optometrists, the 20:20:20 rule states that computer users should look away from their computer every 20 minutes to gaze at a distant object, at least 20 feet away, for 20 seconds. The 20:20:20 rule allows you to relax your eyes and focus on different objects at a farther distance, rather than staring at the closest object to us, namely our monitor.
We also recommend, blinking during these breaks. Viewing a monitor tends to decrease the number of times we blink, contributing to eye dryness and irritation. Simply closing your eyes a few times for short 10-second periods can help with this.
These are a few recommendations that we can immediately implement to reduce eye glare. These solutions are inexpensive but can truly make a difference in the user experience, helping reduce eyestrain and headaches.
As with many things ergonomics, productivity is not compromised by implementing regular breaks or taking the time to adjust your monitor. On the contrary, the more detailed we are about avoiding glare and keeping ourselves within the resting point of accommodation and vergence, the more likely we are to contribute and work efficiently.
Thanks for reading,
Shaul Lent OTR/L, MA, CEAS
Shaul Lent is the Lead Ergonomic Specialist at Ergonomics Advance. He provides individual ergonomic assessments for employees reporting discomfort at their computer workstation and office ergonomics training for HR specialists who want to promote wellness and comfort at the workplace. He can be reached at [email protected].