The 20-20-20 rule is designed to reduce the effects of long durations of near work on the eyes. When working at a close distance, the eyes must work to focus and maintain a single, clear image. The effort it takes to focus at near work becomes greater the longer the near task is performed. To encourage taking frequent, quality breaks, follow the 20-20-20 rule. This rule states that for every 20 minutes of near work you should take a 20-second break and look at something at least 20 feet away.
Why the 20-20-20 Rule is Needed
As the amount of near work, including using a computer, tablet, or phone, increases in the daily routine, the symptoms of eye strain have increased in prevalence.
Eye strain is classically a result of overworking the focusing muscles in the eyes.
The muscles which cause the eyes to turn inward are used to look toward a target that is close to the face.
In order to have a clear image, the eyes must use accommodation. Accommodation is the process of changing the shape of the lens inside the eye to have a clear image.
When to Use the 20-20-20 Rule
The 20-20-20 rule is designed to reduce the symptoms of eye strain. Any time the eyes are straining to focus at a close distance, the eyes can develop symptoms of eye strain.
The most common symptoms of eye strain are a feeling of pulling behind the eyes, a headache after near work, and blurry vision after prolonged near work.
If the eyes have a pulling sensation, it is usually due to the muscles which cause the eyes to turn inward. These muscles can become fatigued and cause a sensation that is often described as a pulling or tightening behind or around the eyes.
Headaches are a common symptom of eye strain. Particularly, headaches that are in the front of the head, just above the eyes, or across the forehead can be associated with eye strain.
These headaches may occur after even a short duration of near work due to the use of accommodation to focus.
Blurry vision with near work is often a symptom of a problem with the focusing system of the eyes. This blurry vision can be intermittent or constant depending on the exact cause of the blurry vision.
How the 20-20-20 Rule Reduces Eye Strain
If eye strain is experienced with near work, it is typically worse after a prolonged time of the near work.
By taking frequent and high-quality breaks, the symptoms of eye strain can be alleviated.
The 20-20-20 rule allows the eyes to have a break from the near-focus task and relax the muscles of accommodation and convergence.
If during the break from near work, you do not focus far enough away, such as looking at a phone or reading a book, the eyes do not truly get a break from accommodation and convergence.
For this reason, the 20-20-20 is the perfect option for both frequency and the type of break from near work.