When Jeffrey Anshel, OD, created the 20-20-20 rule in the late 1990s to help combat the growing problem of digital eye strain, he suggests he never intended to advertise the idea as unfaltering scientific truth.1 Yet, the concept has spread like wildfire among the eye care community, despite a dearth of supporting evidence.
The rule advises individuals to take breaks from digital screens every 20 minutes and gaze at an object positioned 20 feet away for 20 seconds, with the aim of easing the ocular demands associated with near work. Initially devised as a simple piece of advice that Dr Anshel could quickly convey in media interviews, as a play on the 20/20 concept that many laypersons are familiar with as it relates to vision, the rule somehow became a standard digital eye strain prevention strategy recommended by optometrists, professional associations, and public health organizations.1-4
The optometric community acknowledges that digital eye strain is now a ubiquitous problem among individuals using digital devices, but prevalence rates vary between studies.5
Contributing Factors to Digital Eye Strain
“Generally, patients presenting with [digital eye strain] symptoms are over the age of 35, though anecdotally, younger patients are increasingly having this issue due to multiple hours of small screen time each day,” said Raj K. Maturi, MD, a practicing retinal specialist and clinical spokesperson for the American Academy of Ophthalmology. Research also suggests that additional predictors of digital eye strain include female sex, computer use exceeding 6 hours per day, and a lack of breaks from computer use, among other factors.6
“Focusing for hours on a small screen with the neck bent down increases the strain on neck muscles, and looking for long durations at a near object causes stress on the eye muscles and eyestrain, with resulting issues such as accommodative dysfunction and convergence insufficiency,” Dr Maturi explained.
Digital eye strain can lead to a range of symptoms, which include visual blur, diplopia, ocular dryness and redness, and headaches — all of which can negatively affect quality of life and academic performance, according to Andrew D. Pucker, OD, PhD.
Lack of Evidence for 20-20-20 Rule
While many experts may have embraced the 20-20-20 rule as a go-to intervention, recent studies cast doubt on its effectiveness. Noting the lack of peer-reviewed evidence to support its clinical benefits, researchers put the popular technique to the test in a 2023 study.7
In 4 separate sessions, 30 participants (age range, 21-31 years) completed a 40-minute reading task on a tablet computer, with 20-second breaks permitted every 5, 10, or 20 minutes during the first 3 sessions. No breaks were allowed during the last session. Participants were tested for reading speed and task accuracy during each session, and they completed questionnaires to report any ocular and visual symptoms they experienced during the task.
Study participants demonstrated a significant increase in symptoms following the completion of each task compared with baseline (P <.001), while the breaks showed no significant effect on symptoms (P =.70), reading speed (P =.93), or task accuracy (P =.55).
“We didn’t rule out the idea that taking breaks is ineffective, but what we did find is that 20-second breaks every 20 minutes was ineffective,” noted study co-author Mark Rosenfield, PhD, diplomate in Binocular Vision, Perception, and Pediatrics, and professor at the State University of New York College of Optometry. “My suspicion is that the breaks need to be longer than 20 seconds – perhaps 1 or 2 minutes, but the optimal frequency is still to be determined.”
Similarly, Dr Pucker said that there is little or no data supporting the benefits of the 20-20-20 rule and emphasized that Dr Anshel never intended for the concept to be taken as scientific fact. “He was trying to create something catchy, so people would remember to take breaks,” he explained. “Simply suggesting breaks from near work could reduce eye strain and myopic development – for example, my article on myopia and the 20-20-20 rule found evidence that 5-minute breaks every hour could be beneficial, based upon animal studies.”8
The 20-20-20 rule may be a helpful tool to interrupt the frequent “doom scrolling” that has become increasingly common among digital device users. “Habituating oneself to look away from a near task every 20 minutes is a guideline that allows one to relax the eyes,” according to Dr Maturi.
Beyond Breaks: Addressing Eye Strain
Given the high prevalence of frequent screen use, Dr Pucker said eye doctors are likely “seeing patients with [digital eye strain] on a daily basis, and they need to be actively screening for it.”
Dr Rosenfield questions whether optometrists are conducting a complete and thorough case history to identify these issues. “Simply asking if patients use a computer or testing patients at 16 inches in primary gaze is inadequate,” he said. “Many people today use multiple devices, ranging [from] smartphones to desktop computers, and each of these has very different font sizes, viewing distances, and gaze angles.”
He advised clinicians to ask every patient about which devices they use and discuss the appropriate viewing distance and refractive error corrections to be worn with each device. The American Optometric Association recommends positioning computers with the center of the screen roughly 4 or 5 inches below eye level and 20 to 28 inches away from the eyes.3 Other recommendations include positioning screens to reduce glare from light sources, using anti glare screens, and blinking frequently.3
“The number one treatment for [digital eye strain] should be a comprehensive eye examination to detect and correct any underlying refractive error or binocular vision anomaly,” Dr Rosenfield said. “Dry eye therapies such as the use of ocular lubricants and blink exercises may also be helpful.”
According to Dr Rosenfield, there also remains a need for an objective indicator of digital eye strain, as the current screening approach primarily relies on subjective symptom questionnaires. “If we can identify an objective measurement for the condition, this will be valuable to assess new treatment options,” he said.
Employing the 20-20-20 rule may not be a detriment to ocular health, and the popular catchphrase may even serve a purpose in highlighting the importance of limiting screen time. Research acknowledges the risks associated with excess digital device use — risks that include not only digital eye strain, but pediatric myopia — and some countries are enacting policies to combat this epidemic.9 Despite these known risks, digital device use does not appear to be waning. A 2023 investigation revealed that approximately 40% of US workers work remotely in some capacity (28% hybrid vs 12% fully remote).10
As the effects of digital eye strain continue to present themselves in optometry offices, clinicians must continue to promote an awareness of the disorder. More importantly, however, optometrists must rely on more scientifically-substantiated methods of alleviating digital eye strain to enable them to provide their patients with evidence-based treatment.
- Anshel J. Letter to the editor: 20-20-20 rule: are these numbers justified? Optom Vis Sci. 2023;100(4):296. doi:10.1097/OPX.0000000000002006
- Boyd K. Computers, digital devices and eye strain. American Academy of Ophthalmology. Published March 3, 2020. Accessed July 18, 2023. https://www.aao.org/eye-health/tips-prevention/computer-usage
- Computer vision syndrome. American Optometric Association. Accessed July 18, 2023. https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/computer-vision-syndrome?sso=y
- Tips to prevent vision loss. Centers for Disease Control and Prevention. Reviewed August 10, 2021. Accessed July 18, 2023. https://www.cdc.gov/visionhealth/risk/tips.htm#:~:text=Try%20the%2020%2D20%2D20,and%20your%20contact%20lenses%E2%80%94properly.
- Wolffsohn JS, Lingham G, Downie LE, et al. TFOS lifestyle: impact of the digital environment on the ocular surface. Ocul Surf. 2023;28:213-252. doi:10.1016/j.jtos.2023.04.004
- Zayed HAM, Saied SM, Younis EA, Atlam SA. Digital eye strain: prevalence and associated factors among information technology professionals, Egypt. Environ Sci Pollut Res Int. 2021;28(20):25187-25195. doi:10.1007/s11356-021-12454-3
- Johnson S, Rosenfield M. 20-20-20 rule: are these numbers justified? Optom Vis Sci. 2023;100(1):52-56. doi:10.1097/OPX.0000000000001971
- Pucker AD, Gawne TJ. Fighting myopia with intermittent nearwork breaks: 20 seconds every 20 minutes might not be enough time. Optom Vis Sci. 2023;100(1):31-32. doi:10.1097/OPX.0000000000001965
- Dhakal R, Shah R, Huntjens B, Verkicharla PK, Lawrenson JG. Time spent outdoors as an intervention for myopia prevention and control in children: an overview of systematic reviews. Ophthalmic Physiol Opt. 2022;42(3):545-558. doi:10.1111/opo.12945
- Goldberg E. Do we know how many people are working from home? New York Times. Published March 30, 2023. Accessed July 17, 2023. https://www.nytimes.com/2023/03/30/business/economy/remote-work-measure-surveys.html#:~:text=Last%20month%2C%20the%20survey%20found,remain%20entrenched%20in%20certain%20industries.