Computer Vision Syndrome: Remediation

Continued from: Computer Vision Syndrome

The most typical symptom of Computer Vision Syndrome (or CVS) is 'Dry eye'. Most common factors that can cause 'Dry eye' are:

• Decreased blink rate
• Lid conditions
• High gaze angle
• Low humidity
• Contaminants in environment
• Air conditioner vents

How to take care of 'Dry eyes'?

• Blink more (15-20 times/min)
• Treat lid conditions – Meibomitis/ Blepharitis
• Artificial Tears
• Air conditioner vent away from the face
• Low gaze angle
• Ergonomics

While most other factors are manageable and controllable, 'Ergonomics' is usually ignored. Apparently, it is the biggest contributor causing CVS.

Ergonomics is 'the study of designing equipment and devices that fit the human body, its movements, and its cognitive abilities. The proper ergonomic design is necessary to prevent repetitive strain injuries, which can develop over time and can lead to long-term disability.'

Ergonomics is assessed over four these categories:

• Lighting, Glare and Reflection
• Monitor, Keyboard and Mouse
• Posture
• Visual Hygiene

Lighting

• Position of lighting
• Type of lighting: Indirect over Direct

Direct Lighting

Indirect Lighting

Advantages of Indirect Lighting:

• Distributes light more evenly than direct lighting systems
• Eliminates glare and shadows

Disadvantages:

• Higher installation cost
• Fixture reflectors and room surfaces must be cleaned regularly to ensure maximum performance

Management of Glare and Reflections

• Add dimmer switches to overhead lights/coverings on fluorescent lights.
• Relocate lamps causing reflections on the screen.
• Non-reflective paint /coverings on walls facing computer.
• Eliminate exterior light –drapes, blinds, shades with a screen/partition behind the computer to reduce light /overhead glare.

Black on white (the High contrast between screen background and characters)

• Equipment with brightness controls
• Brightness match
• Work in downgaze, angling of monitor
• Glare guard -an optically coated glass anti-glare filter on a CRT monitor

Monitor

• The working distance of 50-60 cm
• Centre of the screen to be 4 –9 inches below eye level
• The 3x test - Character size should be three times the size of threshold recognition

Chair

• Height adjustment
• Knee angle more or equal to 90 Degree
• Footrest
• Back straight
• Lower back support
• Arms rest
• Direct in front

Keyboard / Mouse

• Lower than elbow
• Nearer to the body
• To be flat

Keyboard Posture

Mouse Posture

Wrist

• Straight while typing
• Wrist pad
• Carpal Tunnel Syndrome

Ideal Workstation

• The distance between eyes and monitor – 20”- 26”
• Monitor angling should be 10 °-20° backwards
• Arm angle –100 °- 90 °
• Straight back – 90 °
• Knee angle - 90 °

Laptop - Ergonomics

• External keyboard placed on an adjustable keyboard platform at elbow height
• Attach an external mouse instead of using the small constricted touchpad or trackball.
• If sitting on a couch, use a pillow to support arms.
• Place the Laptop on a stand, book or another surface that raises it to a height that the screen is viewed without having to bend or rotate the neck.
• Raise the screen To Proper viewing level
• Separate keyboard and Mouse

Ideal Workstation Posture

Ideal Laptop Posture

Visual Hygiene

• Good habits for good vision
• Visual training -exercise
• 10 minutes break every hour
• Blink rate: 15 -20 times/ min
• Organized workstation