Assessment of Visual 

and Neurologic Effects 

Among Video Hub 

Employees ─ New York

Kristin Musolin, DO, MS

Health Hazard Evaluation Report

HETA 2011-0149-3165

September 2012

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2011-0149-3165 Page i

Report Abbreviations................................................................................................ii

Highlights of the NIOSH Health Hazard Evaluation........................iii

Summary .........................................................................................................v

Introduction ...................................................................................................1

Results..............................................................................................................5

Discussion.......................................................................................................8

Conclusions................................................................................................. 10

Recommendations.................................................................................... 10

References.................................................................................................... 13

Contents

Acknowledgments Acknowledgments and Availability of Report................................ 15
Page ii Health Hazard Evaluation Report 2011-0149-3165

Abbreviations

1080i 1080 interlaced

3-D Three-dimensional

HHE Health hazard evaluation

LCD Liquid crystal display

LED Light emitting diode

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OSHA Occupational Safety and Health Administration

PPE Personal protective equipment

TV Television

VHO Video hub office 
Health Hazard Evaluation Report 2011-0149-3165 Page iii

The National Institute 

for Occupational Safety 

and Health received 

a request for a health 

hazard evaluation at a 

video hub office in New 

York. The union submitted 

the request because of 

concerns about visual and 

neurological symptoms 

among employees who 

monitored television 

displays.

Highlights of the

NIOSH Health

Hazard Evaluation

What NIOSH Did

● We visited the facility on February 2–3, 2012.

● We evaluated employees’ visual and neurologic symptoms 

and workplace conditions.

● We measured viewing distances from desktop workstations to 

wall monitors.

● We talked with employees about their work and health concerns.

● We reviewed employee medical records and logs of workrelated injuries and illnesses.

What NIOSH Found

● The video hub office was well maintained.

● Most employees reported multiple symptoms when at work. 

The most commonly reported symptoms were eyestrain, 

headache, and body aches.

● The distance from the first row of desktop monitor 

workstations to the wall monitors was approximately 84 

inches. The average distance from the user to the desktop 

monitor was 37 inches. As a result, looking back and forth 

between nearby and far objects that are different distances 

may cause eyestrain.

● The desktop monitors varied in brightness and contrast 

settings. Some monitors were not at the same level or angle.

● The chairs in the video hub were adjustable, but did not 

have headrests.

● Video hub office technicians worked 10-hour shifts with 4 

days on and 3 days off. Every 2 months technicians rotated 

between 5 different shifts covering 24 hours. Shift work 

may increase health and safety risks by disturbing sleep and 

circadian rhythms.

● Most employees thought management did an adequate 

job of letting them know what was being done to address 

workplace concerns.

What Managers Can Do

● Provide employees with adjustable ergonomic chairs. These 

will help increase employee comfort and improve their ability 

to view multiple monitors.
Page iv Health Hazard Evaluation Report 2011-0149-3165

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

 

● Use computer monitors that are height adjustable and have 

non-glare screens. Regular cleaning should improve visibility 

and reduce eyestrain.

● Encourage employees to use proper posture when viewing 

monitors. Also, encourage employees to take breaks to stretch 

and rest their eyes.

● Encourage employees to report any health concerns that may 

be related to their work to their health care provider.

● Promptly address any concerns that employees report. The 

employees should be notified about what is being done to 

address the concern and what future actions are planned.

● Evaluate work shift scheduling. Keep consecutive night shifts 

to a minimum, and consider forward rotating shifts.

What Employees Can Do

● Report all health and safety concerns to your manager.

● Seek care from an occupational health physician if you have 

symptoms or concerns related to your work. If you are having 

problems with your eyes you should see an optometrist or 

ophthalmologist.

● Wear the appropriate personal protective equipment. Laser 

glasses, 3-D glasses, and earmuffs may protect you while at work.
Health Hazard Evaluation Report 2011-0149-3165 Page v

NIOSH evaluated 

concerns that excessive 

visual stimuli in their work 

environment contributed 

to employees’ visual and 

neurological symptoms. 

Most employees reported 

one or more health 

symptoms that may have 

been related to their 

job duties. NIOSH made 

ergonomic and procedural 

recommendations to 

decrease symptoms 

and improve employee 

comfort.

Summary

In September 2011, NIOSH received a union request for an 

HHE concerning visual and neurological symptoms among 

employees at a VHO in New York. Employees thought 

their symptoms may have been associated with long-term 

monitoring of multiple standard and high definition fiberoptic fed TV displays for audio and video imperfections. 

NIOSH conducted a site visit on February 2–3, 2012.

We interviewed employees in a private setting to discuss 

their health and workplace concerns and reviewed medical 

records. The distances between video monitors and employee 

workstations were measured. During our interviews, 10 

of 12 employees reported one or more health symptoms; 

most reported eyestrain, headache, pain or body aches, and 

drowsiness. A history of migraine headaches that occur more 

frequently at work was reported by 3 of 12 employees. We 

found the distance from the first row of desktop monitor 

workstations to the wall monitors was approximately 84 

inches. The average distance from the user to the desktop 

monitor was 37 inches. As a result, looking back and forth 

between nearby and far objects that are different distances 

may cause eyestrain. We provided recommendations to 

managers and employees to help lessen eye strain and 

ergonomic complaints while at work.

Keywords: NAICS 517210 (Wireless Telecommunications Carriers 

[except Satellite]), neurologic symptoms, television monitors, 

computer, telecommunication, LED, vision symptoms, video hub 

office 
Page vi Health Hazard Evaluation Report 2011-0149-3165

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Health Hazard Evaluation Report 2011-0149-3165 Page 1

Introduction

In September 2011, NIOSH received a request for an HHE at a 

telecommunications VHO in New York. The Communication 

Workers of America local union submitted the request on behalf 

of VHO employees who were concerned about health effects that 

included headache, nausea, and visual impairments (blurred vision, 

double vision, and eyestrain). Some employees felt these symptoms 

were a result of continuous visual monitoring of multiple standard 

and high definition fiber-optic fed TV and computer displays, 

including a 3-D monitor. Prior to the site visit, we requested and 

received a roster of current employees and OSHA Form 300 Injury 

and Illness Logs from 2005–2010. Managers also provided pictures 

of the VHO and a description of video hub technician general 

duties, qualifications, and training.

During the site visit on February 2–3, 2012, we met with union, 

management, and employee representatives to discuss the NIOSH 

HHE Program and the request. We toured the video hub area, 

telecommunications equipment room, equipment building 

room, equipment workshop room, antenna room, and generator 

room. During the tour, we observed work processes, practices, 

and workplace conditions, and spoke briefly with employees in 

the video hub area. We also interviewed a sample of employees 

during the site visit and by phone. Managers, engineers, and video 

hub technicians from morning, day, and night shifts participated 

in these voluntary, confidential interviews. We also measured 

workplace viewing distances to determine if the distances complied 

with the standards for ergonomic workplace design.

Background

The building that housed the VHO was constructed in 1929; 

however, the VHO itself was constructed in June 2008 on the 

building’s second floor. The company operated 12 VHOs plus other 

smaller remote sites nationwide. VHOs take channel signals for their 

region and prepare them for distribution to customers. Employees 

include managers, engineers, and VHO technicians; the technicians 

are represented by the Communication Workers of America.

Process Description

The telecommunication facility was a 24-hour operation where 

employees monitored displays for signal degradation as well as 

audio and video imperfections to maintain acceptable picture and 
Page 2 Health Hazard Evaluation Report 2011-0149-3165

Introduction

 (continued) sound quality. Channels were monitored in standard and high 

definition. Specifically, VHO technicians analyzed and distributed 

content through a fiber-optic network for three local and national 

areas. Technicians also monitored the emergency alert system and 

placed advertisement content locally and nationally. Advertisers 

sent their commercials to the VHO, and the technician inserted 

them into programming as required.

Work schedules for VHO technicians included five shifts:

1. 12 p.m. to 10 a.m.

2. 6 a.m. to 4 p.m.

3. 10 a.m. to 8 p.m.

4. 4 p.m. to 2 a.m.

5. 8 p.m. to 6 a.m.

VHO technicians rotated every 2 months with 4 days on and 3 days 

off for 10-hour shifts. For example, five employees worked for the 

first half of the week, and another five employees worked the last 

half of the week. However, some did not rotate because of seniority 

or medical reasons. Engineers rotated every 3 months between day 

and night shifts and could take calls from home. Managers worked 

5 days a week and were on call 24 hours a day, 7 days a week. 

Video hub technicians had a mandated 30-minute lunch and two 

15-minute breaks per shift. Inside the VHO were a total of 56 fiberoptic fed video monitors and computer desktop flat panel monitors 

(Figures 1 and 2) as follows:

● Nine workstations, with three rows containing three 

workstations each. Each workstation had four 20-inch computer 

desktop flat panel monitors, for a total of 36 monitors.

● A 42-inch 1080i LCD used to monitor an unmanned local 

VHO for security reasons

● A series of set top cable boxes with three 42-inch LED 1080i 

monitors used for troubleshooting on both sides of the VHO 

area desktop environment (six total)

● A 50-inch 3-D monitor that was used for programming on a 

limited basis

● Six 42-inch (two brands) LCD 1080i monitors with fixed tilt 

about 30 degrees downward from the wall

● Six Barco branded (highest resolution) displays with 

“thumbnail widgets” (split screens) parallel to the wall
Health Hazard Evaluation Report 2011-0149-3165 Page 3

Introduction

 (continued)

Figure 1. On the wall are fiber-optic fed video monitors in the VHO–

Barco branded and 42-inch LCD displays.

Figure 2. Employee surveying the fiber-optic fed video wall monitors 

(channel scan) and “thumbnail widgets” (split screens) on Barco 

branded screens in the VHO.

VHO employees typically sat in the first row of workstations closest 

to the wall monitors in the VHO area. This set-up facilitated access 

to the set top cable boxes for calibrating the remote control to the 

display monitor.

VHO employees were responsible for identifying audio and video 

impairments inside and outside the VHO. They maintained 

primary and secondary channels, video on demand, national and 
Page 4 Health Hazard Evaluation Report 2011-0149-3165

Introduction

 (continued) local content reception and processing, advertisement inserts, and 

media guide content inserts. Employees reported that some of 

their duties included the following:

● Performing routine checks every 3 hours

○ Verifying fiber-optic blackout lists on a website and 

printing a paper copy

○ Visually scanning standard and high definition channels 

for approximately 30–45 minutes or up to 11⁄2 hours if 

only one employee on duty per shift

○ Checking thumbnail widgets on Barco branded screens

○ Checking the power generator in case of a power outage

○ Auditing and scanning parts (occasionally)

○ Checking the emergency alert system and video on 

demand by purchasing a video and checking the main 

functions

○ Checking the telecommunications equipment room

● Surveilling video broadcast network and equipment

● Inspecting VHO equipment and maintenance on computer 

desktops

● Performing fiber-optic wire operations occasionally on night 

shift during a maintenance window event (12 a.m. to 3 a.m.)

● Continuous monitoring for alarms or failed network paths

The telecommunications equipment room was divided into 

networks for three locations. Each network included numerous 

encoders for video multiplex streaming, optical fiber routers, 

servers for monitoring VHO desktop flat panel computers, 

wireless routers for remote access, power supplies, service and 

media guide computers, encryption modulators, satellite receiver 

services, and emergency alert system computers.

The equipment building room was used by contractors to build 

equipment that was transferred to the care of the telecommunication 

network facility for maintenance. The equipment workshop room 

was used to store spare parts, cables, and tools. The antenna room 

provided antenna grounding for protection from lightning strikes. 

The power generator room was downstairs from the VHO floor and 

had a 750 kilowatt backup generator.
Health Hazard Evaluation Report 2011-0149-3165 Page 5

Results

OSHA Form 300 Logs of Work-Related 

Injuries and Illnesses

The OSHA Logs for years 2005–2010 included four injuries. One 

of the injuries entailed lower back strain as a result of overexertion 

in a VHO employee. The remaining injuries were in field 

technicians and a central office worker.

Employee Interviews 

We interviewed in person or by phone 12 of 15 employees who 

were present on the day of the site visit. Three employees declined 

interviews. Employees were asked to discuss their work responsibilities 

and practices, PPE use, and any work-related health concerns.

PPE used in the VHO varied among the employees. A few 

employees chose to wear earmuffs (provided by the company) 

in the VHO because of the distraction and noise from multiple 

audio signals. Most employees reported wearing earmuffs in the 

telecommunications equipment room only if they anticipated 

a longer stay when repairing or investigating a problem. A 

previous OSHA site visit found noise levels in this room were 

82–85 decibels and did not exceed the permissible exposure 

limit. Two employees reported not wearing laser glasses because 

they never evaluated fiber-optic cables. All employees reported 

wearing 3-D glasses when they checked 3-D programming. When 

asked about regular comprehensive eye exams, seven employees 

reported receiving exams within the last year from their personal 

optometrist; one of these employees was previously diagnosed 

with phlebitis and dry eye, and one was diagnosed with vestibular 

migraines associated with photophobia. Four employees reported 

receiving eye exams every 2 years; one noted needing a stronger 

eyeglass prescription. One employee reported his last eye exam was 

3 years ago.

Participation and Demographics

The VHO had 15 employees, including 5 managers. Demographics 

of the 12 interviewees were as follows: 12 (100%) males, average 

age of 49 (range 31–65). The average length of employment with 

the company was 10 years (range 2–29 years; median 4 years). For 

the seven VHO technicians interviewed, the average length of 
Page 6 Health Hazard Evaluation Report 2011-0149-3165

Results

 (continued) employment was 3 years (range 2–6 years; median 4 years). Seven 

VHO employees reported that they had previously worked at 

another VHO.

Employee Symptoms

Of the 12 employees interviewed, 10 reported having health 

problems that began and occurred only at work; some also noted 

progression of symptoms over time. Work-related symptoms are 

listed in Table 1. Eyestrain was the most common work-related 

symptom; it was reported by 8 of 12 (67%) employees. When asked 

what they thought caused their symptoms, employees gave various 

responses, including inactivity, repetition, history of eye and/or 

migraine headache symptoms, shift work, constantly slouching, 

and viewing several broadcasts simultaneously. Specific questions 

related to neurologic conditions were also asked; results are listed 

in Table 2.

Table 1. Work-related symptoms reported by employees (N=12)

Symptoms N 

Eyestrain

Headache

Pain or body aches

Drowsiness 

Tinnitus

Eye fatigue

Body fatigue

Dizziness

Unsteadiness

Blurred vision

Disorientation

Nausea

 8 

 7 

 7 

 6 

 4 

 4 

 4 

 3 

 3 

 2 

 2 

 1 

Table 2. History of specific neurological conditions reported by 

employees (N=12)

Health Condition N 

Migraines

Motion sickness

Nystagmus (involuntary eye movement) 

 3 

 2 

 1 
Health Hazard Evaluation Report 2011-0149-3165 Page 7

Results

 (continued) Medical Record Review

We reviewed medical records for one VHO employee. This 

employee underwent several tests conducted by a variety of medical 

specialists to evaluate their dizziness, migraines, unsteadiness, 

vertigo, muscle aches, and tinnitus (ear ringing). The employee’s 

medical record indicated that the symptoms may or may not have 

been related to work, and the cause of vertigo was unknown. 

A neuro-ophthalmologic consultation failed to determine the 

precise nature of the visual changes. The employee’s physician 

recommended refraining from watching television in social and 

occupational settings.

Health and Safety Concerns 

A common employee concern was the practice of having one 

employee on duty at a time, especially during nights and weekends. 

This required employees to perform routine 3-hour checks 

consecutively, and the concern was that this schedule contributed 

to their symptoms. Most interviewed employees believed that the 

employer appropriately communicated the steps taken to evaluate 

and resolve potential health hazards and issues in the workplace.

Work Practices

When asked how much time they spend continuously watching the 

monitors without a break, most employees reported 30 minutes to 11⁄2 

hours during a channel scan that was performed daily every 3 hours.

Managers stated that in addition to the scheduled breaks 

employees were free to move around the facility. VHO technicians 

reported that when there was only single coverage (usually during 

nights or weekends) they usually worked together with the VHO 

engineers to coordinate breaks.

We measured the distance from the first row of desktop monitor 

workstations (the row most of the VHO employees operate in) 

to the wall monitors. The approximate distance was 84 inches. 

The typical distance from the user to the desktop monitor was 37 

inches. Managers mentioned that the VHO employees’ operation 

workstation location was mostly based on what the employees felt 

most comfortable with, which determined the distance.
Page 8 Health Hazard Evaluation Report 2011-0149-3165

Discussion

VHO employees were required to constantly view several monitors 

at the same time. This may lead to occupational asthenopia 

(eyestrain) and other symptoms that are grouped together under 

the term computer vision syndrome [Anshel 2007]. Computer 

vision syndrome is a complex of eye and vision problems related to 

near-computer use [AOA 2011]. Wall-mounted LCD displays and 

computer monitors on desktop workstations at the VHO facility 

provided opportunity to develop eyestrain and other visual symptoms.

The terms eyestrain and eye fatigue are typically used 

interchangeably and are characterized by internal and external 

symptoms. Internal symptoms include pain and headache. Eye 

dryness and irritation are external symptoms and are usually 

experienced when reading in the presence of glare, flickering light, 

and small font size [Anshel 2007]. According to Gowrisankaran et 

al., decreased blink rate (eye dryness) and eyestrain are associated 

with computer work, cognitive load, and visual stress of a task 

[Gowirsankaran et al. 2012]. Computer-related dry eye may be 

caused by decreased blink rate, high gaze angle, or dry office 

environment [Anshel 2007].

Headaches, blurred vision, and diplopia (double vision) occur 

when the eyes try to compensate for a deficiency in focusing ability 

and uncorrected pre-existing vision conditions [AOA 2011]. Visual 

symptoms result from visual stress on the cross-linkages between 

the processes of accommodation (focusing) and vergence (fixating 

on near and far objects that require visual tracking of moving 

objects) [Barrett 2003]. The resting point of vergence changes with 

viewing angle. For those who exhibit a change in their resting point 

of vergence when looking up and down, a downward gaze angle 

significantly reduces headaches and eyestrain and, to a lesser extent, 

blur and mental fatigue [Tyrrell and Leibowitz 1990]. Focusing on 

targets that differ from the eye’s resting points requires help from 

extraocular and intraocular muscles [Sommerich et al. 2001].

Factors contributing to eyestrain include individual vision 

characteristics, personal work habits, and workplace conditions. 

Other factors such as improper viewing angle/focal distance, 

inappropriate lighting/glare, and screen characteristics such as 

contrast, flicker, and jitter may lead to eyestrain [Clark 1996]. 

Workers over 40 years of age are predisposed to eyestrain 

(headache, eye fatigue, and irritation) because they typically require 

higher illumination levels than younger workers to perform 

the same job [NIOSH 1998]. The World Health Organization 
Health Hazard Evaluation Report 2011-0149-3165 Page 9

recommends an eye examination prior to employment and 

then periodic examinations beyond age 40 years, especially for 

individuals who report musculoskeletal or eyestrain symptoms 

[WHO 1990]. The American Optometric Association recommends 

an eye examination for employees working in occupations that 

are “highly demanding visually or eye hazardous” every 1 to 2 

years for those 18–60 years of age on the basis of an optometrist’s 

professional judgment. Employees age 61 and older should have 

examinations at least annually or more frequently on the basis of 

their personal medical history [AOA 2005].

Eyestrain and other related neurologic symptoms such as 

disorientation, dizziness, unsteadiness, and nausea may be a 

result of motion sickness or viewing objects moving in a virtual 

environment setting (including 3-D properties). Visual vertigo is 

defined as visual environments with large or repetitive moving 

visual patterns [Bronstein 2004]. The trigger for visual vertigo is 

visual; however, the symptoms are vestibular in nature. The goal 

of treatment is to increase tolerance to visual stimuli [Bronstein 

2004]. Most employees, however, reported that vision problems 

experienced while at work ceased once they were at home. 

Individuals with visual vertigo may experience prolonged vision 

problems when not at work, and symptoms may worsen if not 

addressed [AOA 2011]. 

Eye movement occurs with repetitive and static postures during 

computer use. Repetitive posture is repeating a movement for 

an extended period of time, and static posture is maintaining a 

posture for an extended period of time [Anshel 2007]. Not only 

do computer use and video monitor displays create awkward eye 

postures, but they also create awkward musculoskeletal postures. 

In the study by Grandjean et al. most operators preferred to lean 

backward in their chairs even if the chairs were not suitable for that 

posture [Grandjean et al. 1983]. The VHO employees reported a 

similar preference for leaning back in chairs.

Sommerich et al. concluded that computer monitor viewing angle 

significantly affected muscle activity, posture, and performance. 

The approximate distance from the user and the computer monitor 

at the VHO was 37 inches. Sommerich et al. found an average 

preferred distance ranging from 29.5 to 32.7 inches and noted 

that employees did not vary the distance when viewing angles of 

the monitors changed. Sommerich et al. recommend a practical 

distance of 18–30 inches to decrease work-related musculoskeletal 

Discussion

 (continued)
Page 10 Health Hazard Evaluation Report 2011-0149-3165

Discussion

 (continued) symptoms and help maintain an upright posture [Sommerich et al. 

2001]. The recommended visual display distance is between 19.6 

and 39.4 inches [ANSI/HFES 2007].

Because VHO services were provided 24 hours a day, most 

employees usually rotated shifts. Shift work, especially working at 

night, can lead to sleep and circadian rhythm disturbances and 

decreased work performance. Even employees who consistently 

work at night never fully adjust [Rosa and Colligan 1997]. 

Rotating workers forward from evening to night shifts rather than 

backwards from night to evening shifts makes it easier for circadian 

rhythms to adjust [Knauth and Hornberger 2003].

Conclusions The VHO telecommunication work environment, which required 

extensive visual tracking during 10-hour work periods, may 

have resulted in employees reporting adverse health effects. The 

recommendations listed below may improve visual accommodation 

and spatial orientation over long periods of time and should help 

prevent the visual and neurologic symptoms the employees at the 

VHO reported.

Recommendations On the basis of our findings, we recommend the actions listed 

below to create a more healthful workplace. We encourage 

the telecommunication company to use a labor-management 

health and safety committee or working group to discuss the 

recommendations in this report and develop an action plan. Those 

involved in the work can best set priorities and assess the feasibility 

of our recommendations for the specific situation. In most cases, 

the preferred approach is to eliminate hazardous materials or 

processes and install engineering controls to reduce exposure or 

shield employees. Until such controls are in place, or if they are 

not effective or feasible, administrative measures and/or personal 

protective equipment may be needed.

Engineering Controls

Engineering controls reduce exposures to employees by removing 

the hazard from the process or placing a barrier between the 

hazard and the employee. Engineering controls are very effective 

at protecting employees without placing primary responsibility of 

implementation on the employee.
Health Hazard Evaluation Report 2011-0149-3165 Page 11

Recommendations

 (continued) 1. Provide ergonomic chairs with headrests, adjustable height 

controls, lumbar support, and 360-degree swivel capability 

so it is easier to view and access multiple monitors without 

twisting. Padding on the seat, back, and armrests helps 

minimize pressure points and improves comfort.

2. Provide non-glare screens and height adjustable computer 

monitors for employees. Adjust the brightness so it is 

approximately the same as the surroundings; adjust contrast 

as high as possible to eliminate discomfort. Clean screens 

regularly to remove dust that may decrease visibility.

Administrative Controls 

Administrative controls are management-dictated work practices and 

policies to reduce or prevent exposures to workplace hazards. The 

effectiveness of administrative changes in work practices for controlling 

workplace hazards is dependent on management commitment and 

employee acceptance. Regular monitoring and reinforcement are 

necessary to ensure that control policies and procedures are not 

circumvented in the name of convenience or production.

1. Encourage VHO employees to position their body with 

correct upright posture when facing a monitor rather than 

only moving their neck. Adjust the angled monitors so that 

they are at a level to reduce neck strain.

2. Require employees to receive a comprehensive eye exam 

prior to starting work and at a frequency recommended by 

their optometrist or ophthalmologist. They should discuss 

the nature of their work with their optometrist. Employees 

who experience eyestrain and associated symptoms 

(headache; eyestrain; blurry vision; dry eyes; irritated eyes; 

eye fatigue; neck, back, and shoulder pain; and double 

vision) should seek medical attention from an appropriate 

healthcare provider. Employees who wear glasses or contact 

lenses and experience eyestrain should see an optometrist 

to ensure they are wearing the correct eye prescription for 

computer and distant viewing work.

3. Encourage employees to take more breaks to allow for rest 

and recovery. Taking short breaks for 5 minutes every hour 

can give the body and eyes a rest. While on these breaks, 
Page 12 Health Hazard Evaluation Report 2011-0149-3165

Recommendations 

(continued) standing up and doing stretches or physical movement will 

reduce discomfort. Encourage employees to consciously 

think about blinking often.

4. Continue monthly safety and health committee meetings to 

provide appropriate training and discuss topics specific to 

hazards in the VHO. A member of the safety management 

team should communicate directly with employees who 

report health and safety concerns to ensure the concern is 

understood and if applicable, explain what steps are being 

taken to address the issue.

5. Establish a system to report concerns and meet with 

appropriate personnel (supervisors, managers, healthcare 

providers, and others).

6. Advise employees that, in general, the recommended 

viewing distance from the desktop flat panel monitor to 

the employee is 18–30 inches; however, the exact distance 

should be a matter of personal preference based on vision 

requirements.

7. Review the work shift plan. Keep consecutive night shifts to a 

minimum. Rotate workers forward from day to night shifts.

Personal Protective Equipment 

PPE is the least effective means for controlling employee 

exposures. Proper use of PPE requires a comprehensive 

program, and calls for a high level of employee involvement and 

commitment to be effective. The use of PPE requires the choice 

of the appropriate equipment to reduce the hazard and the 

development of supporting programs such as training, changeout schedules, and medical assessment if needed. PPE should 

not be relied upon as the sole method for limiting employee 

exposures. Rather, PPE should be used until engineering and 

administrative controls can be demonstrated to be effective in 

limiting exposures to acceptable levels.

1. Continue providing all appropriate PPE (3D glasses, laser 

glasses, and ear muffs).
Health Hazard Evaluation Report 2011-0149-3165 Page 13

References

American Optometric Association (AOA) [2005]. Optometric 

clinical practice guideline comprehensive adult eye and vision 

examination. [http://www.aoa.org/documents/CPG-1.pdf]. 

Date accessed: August 2012.

American Optometric Association (AOA) [2011]. The effect of 

video display terminal use on eye health and vision. [http://

www.aoa.org/x5380.xml]. Date accessed: August 2012.

Anshel JR [2007]. Visual ergonomics in the workplace. American 

Association of Occupational Health Nurses 55(10):414–420.

ANSI/HFES [2007]. Human Factors Engineering of Computer 

Workstations (ANSI/HFES 100-2007). Santa Monica, CA: 

Human Factors and Ergonomics Society.

Barrett J [2003]. Minimising side effects of virtual environments. 

DSTO Information Sciences Laboratory DSTO-TN-0478. 

[http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ada415884]. Date 

accessed: August 2012.

Bronstein AM [2004]. Vision and vertigo: some visual aspects of 

vestibular disorders. J Neurology 251(4):381–387.

Clark D [1996]. Workplace evaluation and design. Occup Ergon: 

Theory and Applications, Second Edition 27(1):279–302.

Gowrisankaran S, Nahar KN, Hayes JR, Sheedy JE [2012]. 

Asthenopia and blink rate under visual and cognitive loads. 

Optom Vis Sci 89(1):97–104.

Grandjean E, Hunting W, Pidermann M [1983]. VDT 

workstation design: preferred settings and their effects. Human 

Factors 25(2):161–175.

Knauth P, Hornberger S [2003]. Preventive and compensatory 

measures for shift workers. Occup Med (Lond) 53(2):109–116.

NIOSH [1997]. Plain language about shift work. By Rosa R, 

Colligan MJ. Cincinnati, Ohio: U.S. Department of Health and 

Human Services, Centers for Disease Control and Prevention, 

National Institute for Occupational Safety and Health, DHHS 

(NIOSH) Publication No. 97-145.
Page 14 Health Hazard Evaluation Report 2011-0149-3165

References

 (continued)

 

NIOSH [1998]. Hazard evaluation and technical assistance report: 

Library of Congress Washington, DC. By Moss E, Roegner K. 

Cincinnati, OH: U.S. Department of Health and Human Services, 

Centers for Disease Control and Prevention, National Institute 

for Occupational Safety and Health, NIOSH Report No. 97-0245-

2696.

Sommerich CM, Joines SMB, Psihogios JP [2001]. Effects of computer 

monitor viewing angle and related factors on strain, performance, and 

preference outcomes. Human Factors 43(1):39–55.

Tyrrell RA, Leibowitz HW [1990]. The relation of vergence effort 

to reports of visual fatigue following prolonged near work. Human 

Factors 32(3):341–357.

World Health Organization [1990]. Update on visual display 

terminals and workers’ health. Geneva, Switzerland: World 

Health Organization. 
Health Hazard Evaluation Report 2011-0149-3165 Page 15

Acknowledgments and

Availability of Report The Hazard Evaluations and Technical Assistance Branch 

(HETAB) of the National Institute for Occupational Safety and 

Health (NIOSH) conducts field investigations of possible health 

hazards in the workplace. These investigations are conducted 

under the authority of Section 20(a)(6) of the Occupational Safety 

and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes 

the Secretary of Health and Human Services, following a written 

request from any employer or authorized representative of 

employees, to determine whether any substance normally found 

in the place of employment has potentially toxic effects in such 

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This report was prepared by Kristin Musolin of HETAB, Division 

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communication assistance was provided by Stefanie Evans. 

Editorial assistance was provided by Ellen Galloway. Desktop 

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Below is a recommended citation for this report:

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U.S. Department of Health and Human Services, Centers for Disease Control and 

Prevention, National Institute for Occupational Safety and Health, NIOSH HETA

No. 2011-0149-3165.

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