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ScreenFatigue Digital Eye Strain Index

Calculate your Digital Eye Strain risk and Visual Fatigue Score. Predict dry-eye probability and get a 20-20-20 rule schedule for remote work and VR/AR safety.

Enter Values

0 hours24 hours

Total hours spent looking at digital screens (monitor, phone, VR).

10 cm200 cm

Average distance between your eyes and the primary screen.

Self-assessed brightness level from 1 (dim) to 10 (maximum).

Result

Enter values above and click Calculate to see your result.

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Formula

#
Core Formula
VFS=min(100,H1250+ΔD+ΔB+ΔP)\text{VFS} = \min(100, \frac{H}{12} \cdot 50 + \Delta D + \Delta B + \Delta P)

How it works: The score is calculated by normalizing daily screen hours and applying penalties for short viewing distances (<50cm), high brightness levels, and low blink frequencies.

Worked Example

A remote worker using screens for 10 hours at 40cm distance with high brightness and rare blinking:
1Step 1: Hours Factor = (10/12) * 50 = 41.7
2Step 2: Distance Penalty (40cm) = 5
3Step 3: Brightness Penalty (Level 8) = 9
4Step 4: Blink Penalty (Rare) = 20
5Step 5: Total Score = 41.7 + 5 + 9 + 20 = 75.7
6Step 6: Result: 76/100 (Critical Risk)

What is Digital Eye Strain (Computer Vision Syndrome)?

Digital eye strain, also known as Computer Vision Syndrome (CVS), is a group of eye and vision-related problems that result from prolonged computer, tablet, e-reader, and smartphone use. In 2026, with the rise of remote work and high-immersion VR/AR environments, the incidence of CVS has reached record highs.

  • Blink Synergy: We typically blink 15-20 times per minute, but this drops by 60% when focusing on digital screens, causing dry eyes
  • The 20-20-20 Rule: Every 20 minutes, look at something 20 feet away for at least 20 seconds to relax accommodation muscles
  • Blue Light Impact: High-energy visible (HEV) light from screens can disrupt circadian rhythms and ocular health over long durations
  • Ergonomic Ideal: The top of your monitor should be at or slightly below eye level, approximately 50-70cm from your eyes

This tool helps you quantify your risk and manage your visual health in a digital-first world.

You can also calculate changes using our BMI Calculator, Caffeine Half-Life and Sleep Impact Calculator or Adult Height Calculator.

Digital Strain Risk Matrix

Risk levels based on viewing distance and exposure time.

Daily Hours Distance < 45cm Distance > 55cm
< 4 Hours Low Risk Very Low Risk
4 - 8 Hours Moderate Risk Low Risk
8 - 12 Hours High Risk Moderate Risk
> 12 Hours Critical Risk High Risk

Note: Risk levels are estimates based on standard ergonomic research and may vary by individual sensitivity.

Frequently Asked Questions

What is the 20-20-20 rule?

The 20-20-20 rule suggests that every 20 minutes, you should look at something at least 20 feet away for at least 20 seconds. This helps relax the eyes accommodation muscles and reduces fatigue.

How can I reduce digital eye strain naturally?

In addition to the 20-20-20 rule, ensure your screens are at least 50cm away, match your screen brightness to the surrounding environment, and make a conscious effort to blink more frequently.

Is blue light the only cause of eye strain?

No. While blue light contributes, the primary causes of digital eye strain (CVS) are prolonged near-focusing, reduced blink rate, and poor ergonomic positioning relative to the screen.

Why does my blink rate decrease when using screens?

Studies show that when we focus on high-detail digital content, our spontaneous blink rate drops by up to 60%. This causes the tear film to evaporate faster, leading to dry eyes and discomfort.

How far should my monitor be from my eyes?

Ergonomic standards suggest a distance of 50 to 70 cm (roughly an arm length). Screens that are too close force the eyes to work harder to maintain focus, increasing strain.

Can VR headsets cause more strain than monitors?

Yes. VR/AR headsets place the focal point very close and block out natural light, which can lead to faster onset of visual fatigue and nausea (cyber-sickness). It is even more critical to take frequent breaks.

Medical Disclaimer

This calculator is provided for informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any decisions based on these results. Do not disregard or delay seeking medical advice because of information obtained from this tool.

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