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Ergonomics and Eye Health: The 90-90-90 Posture Meets the 20-20-20 Rule

Vision Science Academy

Haziel Rynjah, Assistant Professor

Jeba Ahmed, M. Optom Student

The Assam Royal Global University, Guwahati, India

In this digital age, we devote long hours towards screens daily for work, study or leisure. (1) Unfortunately, this heavy reliance on screens has resulted in a silent but rising issue called Computer Vision Syndrome (CVS), which involves eye strain, blurred vision, dry eyes and pain in the neck or shoulders. (2,3) The good news? A few simple habits can protect your posture and vision significantly: the 90-90-90 posture rule and the 20-20-20 rule.

The 90-90-90 Posture Rule: Basis of Ergonomic Comfort

Ergonomics is about tailoring the workspace to fit you, not you adapting to that workspace. (4) 90-90-90 is the golden rule for sitting properly when on your computer:

  1. Hips (First 90°): Maintain an upright position where your hips are at a 90-degree angle. You should be sitting up straight with your back against the chair’s backrest.
  2. Position Two: Knees (90°): If your feet do not touch the floor comfortably, use a footrest.
  3. Elbows (Third 90°): Keep the elbows bent at approximately 90 degrees and close to your body with the forearms parallel to the floor. This will lessen tension in your wrists and shoulders.

This posture is beneficial for blood flow and prevents muscle strain that can lead to headaches/cervical pain. (4)

The 20-20-20 Rule: Resting Your Eyes

Whereas posture supports your body, the 20-20-20 rule supports your eyes. Created by Optometrists, it is a straightforward and effective method to alleviate digital eye strain. (5,6) “Look at something 20 feet away for 20 seconds every 20 minutes.” This lenticular recess helps your eye muscles relax from the near-focus enforced by screens, mitigates blinking frequency, and a general dryness that occurs due to extended stares. (6)

Figure 2: This image shows a woman practicing the 20-20-20 rule during digital screen use.

Image Courtesy: https://images.pexels.com/photos/4144830/pexels-photo-4144830.jpeg

How the Two Rules Complement One Another

Consider the 90-90-90 position and 20-20-20 law to act together in favour of entire eye and body wellness as illustrated in Table 1.

Aspect 90-90-90 Posture 20-20-20 Rule
Primary Focus Spine, joints, and muscle alignment Eye muscle relaxation
Key Benefit Reduces physical stress and pain Reduces visual fatigue and dryness
Long-Term Impact Prevents chronic back/neck issues Reduces the risk of CVS and eye strain.

Table 1: This table shows how 90-90-90 Posture and 20-20-20 Rule Complement Each Other.

Conclusion

In a world where screens reign at our work, study and even leisure time, upholding both good posture and visual hygiene is imperative not optional. The 90-90-90 position keeps the body well aligned, relieving stress on the spine and neck and shoulders. The 20-20-20 rule, on the other hand, provides your eyes with the occasional breaks that they need in order to remain relaxed and focused.

These two practices are simple yet potent when combined together to prevent CVS in a holistic way. (2,4) When you practice the 90-90-90 posture and 20-20-20 eye care rule, you’re not only avoiding strain but also ensuring long-term health for both your eyes and spine. So, to sum up: sit right, see right and take good care of those peepers.

References

  1. Sheppard AL, Wolffsohn JS. Digital eye strain: prevalence, measurement and amelioration. BMJ open ophthalmology. 2018 Apr 16;3(1).
  2. Rosenfield M. Computer vision syndrome: a review of ocular causes and potential treatments. Ophthalmic and Physiological Optics. 2011 Sep;31(5):502-15.
  3. Blehm C, Vishnu S, Khattak A, Mitra S, Yee RW. Computer vision syndrome: a review. Survey of ophthalmology. 2005 May 1;50(3):253-62.
  4. Marcus M, Gerr F, Monteilh C, Ortiz DJ, Gentry E, Cohen S, Edwards A, Ensor C, Kleinbaum D. A prospective study of computer users: II. Postural risk factors for musculoskeletal symptoms and disorders. American journal of industrial medicine. 2002 Apr;41(4):236-49.
  5. Brian Chou OD. Deconstructing the 20-20-20 Rule for digital eye strain. Optometry Times. 2018 Mar 1;10(3):21-3.
  6. Talens-Estarelles C, Cerviño A, García-Lázaro S, Fogelton A, Sheppard A, Wolffsohn JS. The effects of breaks on digital eye strain, dry eye and binocular vision: Testing the 20-20-20 rule. Contact Lens and Anterior Eye. 2023 Apr 1;46(2):101744.

About the Author

Haziel Rynjah

Assistant Professor

 

The Assam Royal Global University, Guwahati, India

Jeba Ahmed

M. Optom Student

 

The Assam Royal Global University, Guwahati, India
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