VDTOCCUPATIONALERGONOMICS

VDTOCCUPATIONAL ERGONOMICS

Objectives

Identify and Evaluate the Ergonomic Risk Factors Associated With VDT Environments

Develop Effective Engineering and Administrative Controls to Minimize Exposures Associated With VDT Environments

CURRENT VDT ISSUES

Visual Discomfort Electromagnetic Frequency ( EMF ) Exposure Fatigue / Stress Musculoskeletal Disorders

VISUAL DISCOMFORT

Complaints

Eye Strain - Largest Single Complaint Burning / Itching Eyes Headaches Cataracts

VISUAL DISCOMFORT

Causes

Eye Muscle Strain / Fatigue Dry Eyes Uncorrected Vision Problems Vision Correcting Eyewear - Focusing Difficulties Possible Indoor Air Quality ( IAQ ) Relationship

VISUAL DISCOMFORT

Current Consensus No Evidence That VDT Work Leads

to Visual Damage No Proven Correlation Between VDT Usage

and Cataracts Eye Muscle Strain / Fatigue

– Lighting / Glare– Monitor Height & Distance to Eyes– Visual Concentration on Monitor

Dry Eyes– VDT Environment Less Humid– Eye Blink Rate: 3. 6 / Min VDT vs. 18. 4 / Min Normal

Regular Vision Exams Recommended

VISUAL DISCOMFORT

Control Measures

Eye: Strain / Fatigue / Dryness– Lighting / Glare

» VDT: 50 fc / 500 Lux Optimum Light Level» Office: 100 fc / 1,000 Lux Optimum Light Level» Don’t Place VDT Directly Under

Bright Overhead Lights» Provide Indirect Lighting and Supplement

With Task Lighting» Place VDT Parallel to Windows» Low Reflective Walls / Work Surfaces» Anti-Glare Screens: Last Resort Only

VISUAL DISCOMFORT

Control Measures

Eye: Strain / Fatigue / Dryness–Ensure Monitor Display Quality

» No Apparent Flicker (Older Monitors)» Adjustable Brightness and Contrast» High Resolution and Polarity

–Adjust Monitor Height and Distance» Top Character Line on Screen 15 - 20 Degrees

Below Horizontal Eye Level & Monitor Angled Appropriately Upward

» Eye to Screen Distance 20”- 40” ( Operator Preference Studies 25. 5”- 31” )

VISUAL DISCOMFORT

Control Measures Eye: Strain / Fatigue / Dryness–Eye Focusing / Muscle Defatigue Exercises

» 1 Min. Rest / Exercise Break ( Focus / Refocus ) After 15 Min. Continuous VDT Work

–Remember to Blink Eyes Frequently » > 18 Blinks / Min. Minimum to Refresh Eyes

–Contact Lens Wearers Should SupplementOwn Tears Via Eye / Rewetting Drops

VISUAL DISCOMFORT

Control Measures

Vision / Eyewear–Regular Eye Exams

» New Hire / Transfer» Annual

–VDT Specific Corrective Lenses» Fixed Focal Length» No Bi / Tri-Focals

– Inform Optometrist / Ophthalmologist of VDT Work and Eye / Screen Distance» Some VDT Users May Need a Correction Diff.

From One Needed For Reading / Driving

QUESTIONS ?

ELECTROMAGNETICFREQUENCY (EMF) EXPOSURE

Complaints Reproductive Disorders

– Birth Defects– Stillbirths– Spontaneous Abortions

Cancer– Leukemia– Lymphomas– Central Nervous System

Cataracts Clusters of Reported Problems

EMF EXPOSURE

Concerns

EMF Radiation ?– Ionizing

» X-Ray–Non-Ionizing

» Infrared» Microwave» Radiowave» VLF» ELF

Or Are Other Factors the Real Issue ?

EMF EXPOSURE

Current Consensus Recent Studies Conclude: Emissions of All Types

of EMFs Are Well Below Accepted Occupational and Environmental Health and Safety Limits

No Direct Causal Link Established BetweenVDT Use and Reproductive Disorders, Canceror Cataract Formation

Other Factors ( Smoking, Alcohol, Drugs, Age,Socioeconomic Status, etc. ) Have a Greater Known Effect

Work Stress May be a Factor More Research Needed / Ongoing

to Determine Correlational / Causal Links

EMF EXPOSURE

Control Measures

Monitor / CPU Position– Front: Min. 12” Away = < 1 milligauss (mG)– Rear: Min. 24” Away = < 1 milligauss (mG)

»Essentially “ 0 ” Exposure Minimize Exposure to Known Reproductive

and Carcinogenic Risk Factors –Smoking, Alcohol & Drugs

Workstation and Job Task Design / Redesignto Minimize Work Stress and Maximize Comfort Level

QUESTIONS ?

Fatigue / Stress

Complaints

Generalized Aches and Pains Constant Fatigue Sleeping / Eating Disorders Increased Reliance Upon Coping Mechanisms–Smoking, Alcohol & Drugs

Ulcers High Blood Pressure Coronary Heart / Artery Disease

Fatigue / Stress

Causes

Anxiety About Job Security Anxiety About Ability to Operate Equipment–Computer Phobia

Job Ambiguities Perceived Lack of Control Over Job Concerns About Productivity Shiftwork / OT / Repetitive Work Co-worker / Supervisor / Personal Issues Workstation Design / Layout

Fatigue / Stress

Current Consensus

Lack of Job Satisfaction is Felt by Manyto be the Greatest Stressor

Stress is Related to Overall Job Contentand Not Just VDT Use

Physical Stressors Associated With Workstation Design / Layout Compound Effects of Mental Stressors

Economic Climate Can Significantly Impact Job Fatigue / Stress Levels

Fatigue / Stress

Control Measures

Design / Redesign Jobs to IncreaseEmployee Control and Involvement

Keep Employees Informed About Job Status, Anticipated Changes andProgress in Achieving Goals

Provide Ergonomically Well-DesignedWorkstations

Train Employees in Proper Adjustment of Workstation Features

Promote On / Off Job Wellness Programs

QUESTIONS ?

Musculoskeletal Disorders

Complaints

# 1 - Neck / Shoulder Pain # 2 - Low Back Pain # 3 - CTS / Wrist Pain

MUSCULOSKELETAL DISORDERS

Causes Workstation Design / Adjustment

–Postural Positioning–Dynamic Movement–Static Loading

» Chair, Desk, Keyboard, Monitor, DocumentHolder, Telephone, etc.

Task Design–Concentrated Effort / Repetition

» Physical, Mental & Visual Physical Environment

– Lighting / Noise / Temperature

MUSCULOSKELETAL DISORDERS

Current Consensus

Problems More Closely Related to the TaskThan to the Equipment

Continuous VDT Work Defined as– > 2,000 Reps / Hr– < 30 Sec / Cycle– > 3.5 Hrs / Day Continuous

( > 50 % of Workshift ) Symptom Severity for Upper Extremity

and Low Back Injuries / Discomfort Closely Related to Typing Speed and Length of Time Typing

MUSCULOSKELETAL DISORDERS

Current Consensus Prolonged Excessive Postural Deviations Due

to Poor Workstation Design / AdjustmentSignificantly Contribute to Injury / Discomfort

Appropriate Task and Workstation Design / Adjustment Can Alleviate Majority of Injuries / Discomfort

MUSCULOSKELETAL DISORDERS

Control Measures

Chair - Maximum Adjustability–Height - 5 Caster Base–Seat Pan - Waterfall Edge–Backrest - Lumbar Support–Armrests - Optional but Preferred

Footrest - Adjustable Height / Tilt–Relieves Body Weight Pressure

on Spine– Improves Foot Position Relative

to Chair Height

MUSCULOSKELETAL DISORDERSControl Measures

Monitor–Adjustability For Height and Distance

» Top Character Line 15 - 20 Degrees Below HorizontalEye Level & Monitor Angled Appropriately Upward

» Eye to Screen Distance 20” - 40” ( Operator Preference Studies 25. 5”- 31” )

» Articulating Monitor Stand Keyboard / Mouse

–Detached For Ease of Movement–Adjustability For Height and Distance

» Articulating Tray–Wrist Support and Mouse Pad–Detached Numeric Keypad

MUSCULOSKELETAL DISORDERS

Control Measures Desk / Workstation

–Adjustable Desktop Height–Sufficient Under-Desk Legroom / Clearance–Good Housekeeping

Office Equipment–Document Holder at Monitor Height

» Primarily View Monitor: Monitor in Direct View» Primarily View Document: Document in Direct View

–Calculator, Telephone, etc.» Within Individual Comfortable Reach» Telephone Handset - Shoulder Rest or Headset

MUSCULOSKELETAL DISORDERS

Control Measures

Posture–Head / Neck: Vertical and Forward Facing–Shoulders: Comfortable / Neutral Posture–Upper / Lower Arms: 90 Degree Angle–Wrists: Horizontal–Back: Upright / Lumbar Support / Contact

Backrest at All Times–Upper / Lower Legs: 90 Degree Angle– Feet: Supported by Footrest / Reposition

Periodically

MUSCULOSKELETAL DISORDERS

Control Measures

Posture–Office Equipment Within Individual

Comfortable Reach–Monitor, Keyboard and Chair

Adjustments Are Interrelated– Training: Proper Posture / Adjustment

of Workstation Features» New Hire / Transfer / Periodic Refresher» Supervisor Enforcement

MUSCULOSKELETAL DISORDERS

Control Measures

Task Design–Provide Ergonomically Well-Designed

Workstations–Design / Redesign Jobs to Increase

Employee Control and Involvement– 1 Min. Rest / Exercise Break

(Stretching / Eyes - Focus / Refocus)After 15 Min. Continuous VDT Work– 15 Min. Rest Break (10 Min. Minimum)

after 2 Hrs. Continuous VDT Work (NIOSH)

MUSCULOSKELETAL DISORDERS

Control Measures

Environment–Humidity: 50 - 70 %–Room Temperature: 70 - 75 Degrees ( F ) – Lighting: VDT - 50 fc / 500 Lux Optimum

Office - 100 fc / 1,000 Lux Optimum

QUESTIONS ?

VDTOCCUPATIONAL ERGONOMICS

SummaryEvaluation / Control Measures

Total Job Environment–Workstation Design & Adjustment–Physical Environment– Task Design– Training

Emphasize Good Ergonomics–Design / Redesign / Adjustment

Promote On / Off Job Wellness

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