VISUAL STRESS: EYE STRAIN DUE TO COMPUTER USAGE

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VISUAL STRESS EYE STRAIN DUE TO COMPUTER
USAGE
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COMPUTERS AND VISION

• Dr. Marc Grossman

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Computer Operators Experience Visual Stress due
to

• an increase in the number and complexity of
  necessary eye movements and focusing skills
• poor lighting conditions, glare and distracting
  reflections
• the extended amount of time spent on the computer
  

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Computer Stress Checklist

• Direct symptoms
• Eyestrain
• Indirect symptoms The need for shifts in posture
  and muscular strain resulting from poorly
  arranged workstations

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EYE STRAIN Symptoms (1/2)

• headaches while doing or following computer use
• irritated and/or dry eyes
• blurred vision
• slow refocusing when looking from screen to
  distance objects
• frequently losing place when moving eyes between
  copy and the screen

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EYE STRAIN Symptoms (2/2)

• difficulty in seeing clearly at a distance after
  prolonged computer use
• occasional doubling of vision
• changes in color perception
• lowered visual efficiency
• more frequent errors

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Eye Strain Examination For Computer

• A general eye and health history
• the type of computer work
• the number of hours
• the time of day
• the size, type and color of your screen
• screen characters, positions
• the lighting in the room

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Eye Strain Measurements For Computer

• the type severity and frequency of any symptoms
• A measurement of your visual acuity at distance
  and near
• A measurement of possible prescriptions for
  distance and near working distances
• An assessment of eye focusing ability
• An evaluation of eye coordination and eye
  movement skills

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Computer Use and Vision
Joan Comeau
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OUTLINE

• INTRODUCTION
• CVS (Computer Vision Syndrome)
• GUIDELINE
• EXERCISES

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Causes of CVS

• eye movements
• eye focusing
• eye alignment

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Effects of CVS

• Tired and aching eyes
• Burning eyes
• Dry eyes
• Headaches
• Blurred vision
• Difficulty in focusing
• Double vision

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Guideline

• 15 min. break every 2 hrs
• Eliminate reflections
• Use appropriate spots
• Appropriate screen position
• Visual exercises

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Exercises and Eye Care

• Palming
• Drinking beverages
• Relaxation breaks
• Finger pressure and washing eyes

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Eyestrain The number one complaint of computer
users
Rosemarie Atencio
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CAUSES OF EYESTRAIN
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Causes of Eyestrain

• Primary and Secondary Glare

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Causes of Eyestrain

• Excessive Lighting

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Causes of Eyestrain

• Improper Ergonomics

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Causes of Eyestrain

• Poor Quality Video Display Terminals (VDT)

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Causes of Eyestrain

• Uncorrected or Improperly Corrected Vision

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Optometric Causes of Eye Strain and Ergonomic
Solutions

• Computer Vision Syndrome (CVS)
• Improving Visual Comfort at a Computer
  Workstation
• Visual Ergonomics In The Workplace

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Symptoms of CVS

• Symptoms related to computer work are dose
  related
• Copmuter vs. Printed material
• lower contrast
• pixilated or aliased letters
• reading distance is often greater than 40 cm
• annoying reflections or glare off the screen
• monitors are usually higher than normal reading
  material

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Symptoms of CVS
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Optometric Examination

• 1. Correct any distance refractive error.
• (Working distance, correct height, intermediate
  zone, lens design)
• 2. Correct any near refractive error.
• (Low plus lenses 0.75, etc.)
• 3. Test for binocular anomalies.
• 4. Evaluate for dry eyes.

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Ergonomic Aspects

• 1. Lighting
• 2. Characteristics of the computer display
• (The smallest possible pixel size is preferable,
  Contrast, Faster screen refresh rate)
• 3. Work station design
• about 65 cm distance
• 10-20 degrees or 10-20 cm below eye level

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Improving Visual Comfort at a Computer Workstation

• Lighting
• Screen Reflections
• Flicker Problems
• Display Characteristics
• Workstation Furniture and Arrangement

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Improving Visual Comfort at a Computer Workstation

• Lighting
• Eliminate bright light
• Avoid white reflective surfaces
• Use indirect lighting systems
• Screen Reflections
• Use an antireflection screen
• cover the sources of the reflections
• Use dark characters on a light background

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Improving Visual Comfort at a Computer Workstation

• Flicker Problems
• Display Characteristics
• Monochrome monitors
• Maximized resolution
• Workstation Furniture and Arrangement

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Visual Ergonomics In The Workplace

• The Terminal
• Eye Position
• Glare
• Computer Glasses
• Vision Therapy
• Computer Vision Testing
• Eye Self-Care

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Visual Ergonomics In The Workplace

• The Terminal
• Eye Position
• Paper 30-40 cm 40 degrees
• Monitor 20-25 cm below eye of sight
• Glare
• offices are much too bright for terminal work.
• Computer Glasses

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Visual Ergonomics In The Workplace

• Vision Therapy
• Computer Vision Testing
• (VDT-related visual stress)
• on-line questionnaire
• vision tests
• Eye Self-Care

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Eye Self-Care ("3 B's)

• Blink
• - normally 12-15 times a minute
• Breathe
• -relax the eye muscles
• Breaks
• -Micro-Break
• -Mini-Break
• -Maxi-Break