Ergonomic Evaluation of 

Surfacing and Finishing 

Tasks during Eyeglass 

Manufacturing – 

Minnesota

Jessica G. Ramsey, MS, CPE

Loren Tapp, MD, MS

Health Hazard Evaluation Report

HETA 2010-0114-3168

November 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 2010-0114-3168 Page i

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

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

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

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

Assessment.....................................................................................................3

Results..............................................................................................................4

Discussion.................................................................................................... 17

Conclusions................................................................................................. 18

Recommendations.................................................................................... 19

References.................................................................................................... 23

Contents

Acknowledgments Acknowledgments and Availability of Report................................ 32

Appendix A Ergonomic Evaluation Criteria.............................................................. 24

Appendix B Tables............................................................................................................. 25
Page ii Health Hazard Evaluation Report 2010-0114-3168

Abbreviations

HHE Health hazard evaluation

MSD Musculoskeletal disorder

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OSHA Occupational Safety and Health Administration

UE Upper extremity

WMSD Work-related musculoskeletal disorder
Health Hazard Evaluation Report 2010-0114-3168 Page iii

The National Institute 

for Occupational Safety 

and Health (NIOSH) 

received a request for a 

health hazard evaluation 

(HHE) at three eyeglass 

manufacturing facilities 

in Minnesota. Managers 

submitted the HHE 

request because of 

ergonomic concerns and 

musculoskeletal disorders 

of employees working 

in the surfacing and 

finishing departments.

Highlights of the

NIOSH Health

Hazard Evaluation

What NIOSH Did

● We evaluated three facilities in November 2010.

● We watched employees doing routine job tasks and 

took video of these tasks. The video footage allows us 

to document employees’ risk factors for work-related 

musculoskeletal disorders (WMSDs).

● We measured the heights of workstations and 

distances that employees reached to do a job task. 

These measurements determine the risk of injury.

● We talked with employees about their work and 

medical history.

● We reviewed occupational safety and health injury and illness 

logs. We also looked at employees’ medical records.

What NIOSH Found

● Employees used awkward postures and repetitive motions in 

their jobs. These factors increased their risk for shoulder, arm, 

elbow, forearm, wrist, hand, and finger WMSDs.

● Employees were also at an increased risk for low back 

WMSDs. This risk was due to repeated bending and twisting.

● The most common WMSDs among finishing and surfacing 

employees were wrist, shoulder, hand, and back disorders.

● The rates of injuries and illnesses at this facility were 

higher than at most other eyeglass manufacturing 

facilities in the United States.

What Managers Can Do

● Design work areas to have a working height of 27–62 inches. 

● Add tables that have adjustable heights so that employees 

can customize the height to their needs. Adjustable lifts with 

rotating platforms should also be added. Take part in safety 

and ergonomic committees.

● Rotate employees to different job tasks after every 

break. All employees should use the same rotation 

pattern.

● Educate employees on ergonomics and WMSDs. This will help 

them recognize and avoid risk factors that can lead to WMSDs.

● Encourage employees to report work-related musculoskeletal 

discomfort. These complaints should be logged to identify jobs 

that need to be modified.
Page iv Health Hazard Evaluation Report 2010-0114-3168

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

 

What Employees Can Do

● Keep heavy loads close to your body when lifting and carrying.

● Learn about and use adjustability features of the 

workstations.

● Take part in safety and ergonomic committees.

● Report injuries and unsafe working conditions to 

your supervisor.

● Seek care from a healthcare provider if you are injured at work. 

The provider should be experienced in occupational health.
Health Hazard Evaluation Report 2010-0114-3168 Page v

Employees were exposed 

to a combination of risk 

factors for upper extremity 

WMSDs. Employees’ 

job tasks often required 

repetitive motions such as 

twisting, reaching, wiping, 

and eyeglass assembly. 

Awkward postures such 

as extended reaches and 

reaches above the head 

were also risk factors. The 

overall rates of OSHAreportable injuries and 

illnesses for all three 

facilities were higher than 

average for the eyeglass 

manufacturing industry. 

However, these rates 

declined in 2010.

Summary

In June 2010, NIOSH received an HHE request from managers 

to evaluate potential ergonomic hazards and MSDs among 

employees at three eyeglass manufacturing facilities in Minnesota. 

The request concerned employees working in the surfacing and 

finishing departments. 

We visited the three facilities on November 16–19, 2010. We 

observed work processes and practices and assessed workplace 

conditions. We videotaped surfacing and finishing tasks. We also 

measured workstation heights and reach distances. We talked with 

employees privately to discuss concerns about the workplace and 

their health. We also reviewed medical records related to MSDs.

We found that employees were exposed to a combination of risk 

factors for developing WMSDs, including awkward postures, forceful 

exertions, and repetitive motions. Of 60 interviewed employees, 

45 reported having current or past MSD symptoms. Review of 19 

employees’ medical records found that most medically documented 

WMSDs involved the wrists, shoulders, hands, and back. Three 

employees had undergone surgery and three (one of whom had 

undergone surgery) were put on permanent work restrictions. 

Comparison of OSHA Form 300 Logs of Work-Related Injuries 

and Illnesses showed higher rates of injury and illness at this facility 

than at other eyeglass manufacturing facilities in the United States 

in 2007–2009, but by 2010, all but one facility’s rates had declined 

to near the national industry average. On the basis of employee 

interviews and OSHA Logs, the most commonly reported MSDs 

were wrist, shoulder, hand, and back disorders.

We provided the facility with recommendations for reducing the 

risk of WMSDs. By designing work areas to have a working height 

of 27"–62" and rotating employees to different job tasks after every 

break, managers can reduce the risk of WMSDs. Training employees 

to recognize and avoid risk factors that can lead to musculoskeletal 

problems and encouraging employees to report work-related 

musculoskeletal discomfort can also reduce employees’ risk of injury. 

Keywords: NAICS 339115 (Ophthalmic Goods Manufacturing), 

ergonomics, WMSDs, finishing, surfacing, prescription lenses
Page 1 Health Hazard Evaluation Report 2010-0114-3168

Introduction

On June 1, 2010, NIOSH received an HHE request from managers 

to evaluate potential ergonomic hazards and MSDs among 

employees at three eyeglass manufacturing facilities in Minnesota. 

The request concerned employees working in the lens surfacing and 

finishing departments.

During November 16–19, 2010, we visited the three facilities. We held 

an opening meeting with managers and employee representatives. We 

observed work processes, practices, and workplace conditions. We 

took video of surfacing and finishing tasks and measured workstation 

design parameters. We also privately interviewed employees to discuss 

their health and workplace concerns and requested medical records 

related to WMSD symptoms possibly caused or aggravated by work 

tasks involving forceful exertions, awkward postures, and repetitive 

motions. On November 19, 2010, we held a closing meeting and 

provided preliminary recommendations to management and employee 

representatives. We sent a letter with our preliminary findings and 

recommendations on December 8, 2010.

Facility Descriptions 

Facility 1 opened approximately 50 years ago and employed 250 at the 

time of our visit. Facility 2 opened around 1979 and also employed 

around 250. Facility 3 was acquired by the company in the late 1980s 

and employed 150. All facilities operated three shifts; however, different 

areas had different start times to allow for continuous workflow. Facility 

1 had tried a 12-hour work shift for 3 years, but had stopped that 

program in May 2010 before our site visit.

Each facility had a health and safety committee that met once a 

month and discussed illnesses, injuries, and concerns. Employees were 

encouraged to use a safety suggestion form/box. Ergonomic concerns 

identified by each facility’s health and safety committee during monthly 

departmental safety audits were provided to an ergonomics committee 

that also met every month. Ergonomics committee members received 

1-day training, provided by the company’s workers compensation 

insurance carrier, on the use of an ergonomics checklist. A safety 

incentive program, “Safety Star Certification,” was in place to reinforce 

ideas and improve involvement. 

The company contracted with an off-site occupational medicine clinic 

for managing work-related injuries and illnesses. If an injury or illness 

occurred, the employee reported it to his or her supervisor and the 

human resources department. If necessary, the employee was sent to 

the clinic for evaluation. Some employees were also evaluated by a 

company-contracted physical therapy group as needed. The supervisor 
Health Hazard Evaluation Report 2010-0114-3168 Page 2

Introduction

 (continued) and human resources staff evaluated the ill or injured employee’s job for 

possible hazards. Temporary employees went through a different process 

and saw a different medical contractor. The company reported that they 

had several light-duty jobs and an aggressive return-to-work program. 

Facility 2 had a mandatory stretching program during work hours.

Surfacing Tasks

Taping 

Employees placed each lens blank in a machine that put a tape/

film on the lens to protect it from heat and damage. 

Blocking

Employees positioned each lens into a blocking machine (Figure 1) 

that used a heated metal alloy to attach a block to the lens. The block 

held the lens in place during grinding, fining, and polishing.

Grinding

A generator ground optical curves into the back of each lens on the 

basis of the prescription.

Tool/Pad 

After grinding, the lens was matched with the proper tool, on the 

basis of prescription, for fining and polishing (Figure 2). 

Fining/Polishing 

Some machines had a single-step process for polishing lenses. 

Others involved a two-step process, and pads on the tool were 

replaced between the steps. At each facility, employees loaded the 

lenses and tools into the polishing machines.

Deblock/Wash

A specially-designed deblocking cup (Figure 3) was used to 

remove the block from the lens. The tape was removed and the 

lens was inspected, washed, and dried before continuing to the 

finishing process. 

Figure 1. Machine used to attach blocks 

to lenses.

Figure 2. Rounds of tools used for 

fining and polishing.
Page 3 Health Hazard Evaluation Report 2010-0114-3168

Introduction

 (continued) Finishing Tasks

Tinting

The lenses could be tinted by placing them into tinting solution.

Verify/Lining/Chucking

For single vision lenses, a verifier machine was used and then 

chucks were attached before the lens was edged. For bifocal and 

progressive lenses, an instrument was used to properly line up the 

lens before placing chucks on them for edging. A chuck is a metal 

or plastic device that is placed on the lens to hold it during edging. 

Sometimes adding a chuck was fully automatic; however, employees 

also added the chuck manually. 

Edging

Edging machines ground each lens to the proper shape for the frame 

and placed a bevel around the edge of the lens. The bevel removed 

the sharp edge from the lens and eased insertion into the frames.

Sanding

Metal or rimless frames required lenses with precise bevels; 

employees sanded these lenses by hand using a tabletop grinder. 

Assembly

Employees inspected the lenses and used a lensometer to verify the 

correct prescription before inserting them into the frames using 

screwdrivers, pliers, and other tools (Figure 4). 

Assessment

Figure 3. Deblocking cup used to 

remove blocks from lenses.

Figure 4. Some of the tools used to 

insert lenses into frames.

We observed surfacing and finishing tasks in the three facilities. 

We took digital videos to document the tasks and measured 

workstation heights. A full description of the ergonomic 

evaluation criteria we used to determine risk factors for WMSDs is 

provided in Appendix A.

We held confidential interviews with employees working in the 

finishing and surfacing departments of the three facilities. The 

interviews focused on medical and occupational histories. These 

included, but were not limited to, work type and duration, workrelated injuries or illnesses, past or current health conditions, and 

possible workplace exposures. We also reviewed medical records of 

employees who had WMSD symptoms and OSHA Form 300 Logs 

of Work-Related Injuries and Illnesses for years 2007–2010.
Health Hazard Evaluation Report 2010-0114-3168 Page 4

Results

Surfacing Tasks

Surfacing tasks described below were similar at each of the three 

facilities; the tools, storage, and machines at the facilities varied 

slightly. Table B1 (Appendix B) contains a list of ergonomic 

hazards in each surfacing area. These hazards are detailed in the 

following paragraphs.

Taping

We measured the location of the taping machine at facility 1. The 

table that held the taping machine was 35" high, and the location 

where lenses were loaded into the machine was 43" high. Tray 

dimensions were 10" wide, 8.5" long, and 3.25" deep; however, 

the tray did not have handles or handholds on the ends, which 

caused contact stress during lifting and carrying. During our 

observation, the incoming trays were stacked five high, and the 

outgoing trays were stacked eight high. These tray heights put 

reach measurements between 511⁄4"and 61". The taping machine 

was activated by a foot pedal. The employee who operated this 

machine was also responsible for retrieving used blocks, letting 

them soak to remove excess alloy, and using that alloy to refill the 

blocking machines. Facility 1 used a square tray to collect alloy, 

facility 2 used a teapot, and facility 3 used a handled pitcher. A 

handled pot or pitcher for pouring provides a power grip, which 

is preferred. Only the tables at facility 1 were adjustable to reduce 

the reach during metal pouring.

Blocking

Blocking employees received stacks of trays from the taping 

area; the height of the stacks varied. The employees used a video 

monitor to verify correct lens alignment. Blocking machines for 

facility 1 were on adjustable tables that could be set at 29"–36". 

Employees were seated for all machines at facility 1 but did not 

seem to have leg clearance under the table or proper workstation 

design because they were seated forward in the chair and did 

not use the backrest. Incoming trays were located to one side of 

the blocking machine and were stacked approximately 10 trays 

high, extending reaches above shoulder height for some of the 

employees (Figure 5). The chucks were in bins on the other side of 

the workstation. A scanner used by employees was located on the 

employees’ left side, causing right-hand dominant employees to 

reach across their body to use it. A video display used for accuracy 
Page 5 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued) of the block placement was shifted off to one side, causing neck 

twisting, but was at the employees’ eye level. After the employee 

attached the block, he or she placed the tray on a tray takeaway 

to the grinding machine; the location of this takeaway caused 

extended reaches. When more trays were prepared than the 

grinding machine could accommodate, employees stacked the 

trays, which resulted in trays stacked above shoulder level. 

Facility 2 had blocking machines for both traditional and digital 

surfacing, and employees did not rotate between the workstations. 

Traditional blocking workstations at facility 2 were all standing 

workstations. The workstation tables were not adjustable, and the 

fixed heights varied between machines, ranging from 35"–39.5". 

Employees were provided anti-fatigue mats; however, because of 

the location of the machine, incoming trays, and the outgoing 

tray conveyor, employees stepped off and on the mats while 

performing the job. The video display for the blocking machine 

was approximately at eye level for the employee observed. Because 

the scanner for this machine was on the employee’s right side, 

reaching across the body as seen at facility 1 was not necessary. 

Digital blocking workstations at facility 2 were seated workstations; 

the tables were not adjustable. However, if the chair was properly 

adjusted it would probably result in reduced leg room as seen at 

facility 1. Incoming trays were located to one side of the machine 

and were stacked approximately eight trays high, placing the 

highest trays above shoulder height. The scanner was on the 

same side as the incoming trays, so reaching across the body was 

not necessary. The display for the machine was above eye level 

and resulted in neck extension while employees positioned the 

lenses in the blocking machine. The digital workstations had tray 

takeaways for the grinding machines; however, the location caused 

extended reaches. There was some contact stress on the employees’ 

forearms from the placement of their arms while holding the 

lenses in the machine and the edge of the metal table. 

Facility 3 had blocking machines for traditional surfacing; 

employees were specialists working towards technician status so 

they could rotate jobs. The heights of the workstation tables were 

not adjustable. The incoming trays were placed on the employee’s 

left side, but the scanner was on the right of the blocking machine 

and caused the employee to reach across his or her body to use the 

scanner. Employees were observed tapping and pressing on lenses 

to release them, resulting in vibration and pinch forces.

Figure 5. Stacks of trays causing 

reaches above shoulder height.

Figure 6. Conveyor between grinding 

and polishing.
Health Hazard Evaluation Report 2010-0114-3168 Page 6

Results

 (continued) Grinding

Facility 1 grinding generators were loaded automatically from the 

tray takeaway in the blocking department and, after grinding, the 

tray traveled automatically by conveyor to the fining/polishing 

area. Both facility 2 and facility 3 had grinding generators that had 

to be manually loaded and unloaded. At facility 2 the conveyor 

that employees placed trays on for transport to polishing was at 

or above shoulder level for some employees. The height of this 

conveyor was determined by the wall opening and the conveyor 

in the polishing area (Figure 6). There was no conveyor from one 

area to the other at facility 3; however, the carts had enough space 

to hold the multiple trays. Employees were stacking trays on top of 

the machines resulting in reaches of 50"–68" (Figure 7).

Tool/Pad

Each of the facilities had different tool storage methods. The 

tool rounds seen in Figure 3 were used at facilities 1 and 2. They 

required reaching overhead and bending at the back. Tool storage 

had been modified at facility 1 for more frequently used tools 

(Figure 8). Facility 1 had an employee dedicated to pulling tools 

and attaching polishing pads; this workstation also had a pad 

dispenser that separated the pad from the backing and reduced 

pinch forces. Facility 2 had pads on rolls at table height near 

the polishing machines. Facility 3 had pads on rolls above the 

machines, causing employees to reach overhead for the pads. 

Employees in this area restocked used tools that were received after 

polishing.

Fining/Polishing

Each of the facilities had different polishing and fining machines. 

An employee at facility 1 ran five combination polishing machines. 

The employee had a neutral wrist posture when loading and 

removing the tools, but had flexed and deviated wrist postures 

when loading and removing the lenses. The machines had a shelf 

in front to hold a tray; the employee placed trays for the next job 

on top of the machine. The employee used the 6 minutes between 

polishing jobs to soak the used tools to help with pad removal, 

removed the pads using a pinch grip, and threw the pads away. The 

employee then sprayed the tools with an air nozzle to dry them 

before putting them on a conveyor back to the tool area.

Figure 7. Trays stacked on top of 

the machine, resulting in extended 

reaches.

Figure 8. Modified tool storage at 

facility 1.
Page 7 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued) Facility 2 had two different machines for different polishing tasks. 

Two employees each ran 10 polishing machines. One employee 

placed pads on the polishing tools and then placed the tools and 

lenses into the first machine for polishing. These machines required 

a specially designed rod to release and lock the pads in place. The 

rod had a pistol grip; however, employees still had flexed and 

deviated wrists when placing the lenses and tools into the machine. 

Employees also had neck flexion and deviation while making sure 

that the machines were set up properly after installing the lenses. 

Trays were stored on top of the machines during the polishing 

process causing some employees to reach above shoulder level. 

Facility 3 had many different pods of polishing machines. Most 

of the machines had a shelf to hold the trays during the polishing 

process but trays were stacked on top of the machine, resulting 

in extended reaches. We observed an employee using a polishing 

machine at this facility; that employee held the lens during 

polishing, resulting in a vibration exposure.

Deblock/Wash

A special cup was used to remove the block from the lens (Figure 

3). Employees at all three facilities used a variation of the cup; they 

held onto the lens and hit the cup on the table. The lens remained 

in the cup and the block fell to the table. To reduce handling, 

facility 3 had cut a hole in the table (Figure 9) so the block fell into 

a bin. The blocks were sent back to the blocking area where they 

were cleaned before reuse. Employees at facility 2 used a hammer 

to deblock some lenses, which resulted in vibration exposure. 

We observed an employee at facility 2 lifting trays up and over 

an enclosure, resulting in repetitive awkward shoulder postures. 

Employees removed the tape from the lenses before washing and 

drying them; all these activities required a pinch grip. Employees at 

facility 3 had a lens drier that used air to help remove some of the 

water and reduce the amount of wiping required to dry the lenses.

Finishing Tasks

The finishing tasks described below were similar at each of the 

three facilities; the tools, storage, and machines at the facilities 

varied slightly. Table B2 (Appendix B) contains a list of ergonomic 

hazards in each finishing area. These hazards are detailed in the 

following paragraphs.

Figure 9. Collection bin for blocks. 
Health Hazard Evaluation Report 2010-0114-3168 Page 8

Results

 (continued) Tinting

We observed tinting tasks at facility 2 and facility 3. Employees 

placed the lens in a holder that was then placed in a tinting 

solution. If a gradient of color was requested, the employee 

attached the lens holder to a machine that dipped the lens at a 

certain pace. After the lens reached the correct color the employee 

visually inspected the lens and cleaned it with a rag. These job 

tasks required pinch grips when attaching the lens to the holder 

and also when cleaning the lens. Employees did these jobs all day 

without rotation. Not all locations had dedicated exhaust for these 

areas; therefore, employees could be exposed to vapors from the 

heated tinting solution.

Verify/Lining/Chucking

We observed employees at facility 2 attaching chucks and verifying 

proper alignment. This facility had one standing workstation and 

one seated workstation. Employees worked for 4 hours at the 

standing workstation and 4 hours at the seated workstation. The 

legs on the table of the seated verifier prevented the employee from 

rotating the chair to the proper position, requiring him or her to 

twist and rotate his or her back to perform the task. Employees also 

had to reach across their body for parts when in the seated position.

Edging

For digital edging, employees loaded the trays containing the lenses 

into the machine. After edging, the machine automatically sent 

the trays to the assembly area via conveyor. For manual edging, 

employees loaded each lens into the machine. Trays were stacked and 

moved to the assembly area. Because this was mostly an automated 

task we did not observe any employees in the edging area.

Sanding

We observed one employee at facility 1 sanding the edges of the lens 

before assembly. The employee used a pinch grip to hold the lens 

while rotating it around the grinder to bevel the edges more precisely. 

Assembly

Employees visually inspected the lenses and the frames before 

assembly. The lenses were cleaned if necessary before they were 

inserted into the frame. Tools such as screwdrivers, picks, and 
Page 9 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued) clamps were used, all requiring grip forces. After the lenses were 

installed, the employee checked that the frame was straight, 

measured the lenses, and checked the lens with a lensometer. 

All the assembly tasks required a slight neck flexion and various 

wrist postures depending on the tools used. Drill mount jobs 

were more hand intensive and required more tools. Employees 

at facility 1 were required to assemble 19–20 metal/string/plastic 

jobs per hour or 10 drill-mount jobs per hour. Employees did 

not rotate between the two types of assembly. Facility 2 had one 

“ergonomic” workstation that was being pilot tested (Figure 10); 

several employees had tried the workstation and made notes in a 

book about their likes and dislikes. This workstation was height 

adjustable and had task lighting and a tool holder. Employees 

at facility 2 were required to assemble 18 jobs per hour. One 

employee that we spoke to said that she assembled 18 jobs, and 

then inspected 18 to vary the work. Space was limited at most 

workstations, and trays were stacked in places that required 

extended reaches. None of the other workstations were adjustable. 

Facilities 1 and 2 had only seated workstations; facility 3 had 

seated workstations, but the tables and chairs were at a height so 

the employee could choose to stand. One employee at facility 3 

suggested magnetic screwdrivers to reduce the amount of pinch 

force required to hold the screws in place during assembly.

Confidential Medical Interviews

We held confidential interviews with 60 of 235 surfacing and 

finishing department employees from facilities 1, 2, and 3 who 

were available during the shifts we selected. Each of the facilities 

supplied a list of employees who had reported an MSD to their 

supervisor within a year of our site visit. Most of the interviewed 

employees were chosen from this list. The remaining employees 

either requested to be interviewed or were asked to be interviewed 

at random to provide additional perspectives about jobs where we 

had fewer employees on the MSD list or requesting interviews. 

We asked employees, “Do you have any current musculoskeletal 

problems you think are related to your work?” If they answered 

“yes,” we asked “What do you think your musculoskeletal 

problems are caused by?” We defined symptoms of WMSDs as 

persistent pain or soreness of the musculoskeletal system thought 

to be due to awkward postures, forceful exertions, and repetitive 

motion tasks at work and not due to slips, trips, or falls. We 

defined upper extremities to include the shoulder, arm, elbow, 

Figure 10. Adjustable assembly 

workstation.
Health Hazard Evaluation Report 2010-0114-3168 Page 10

Results

 (continued) forearm, wrist, hand, and finger. Table 1 compares demographic 

information for interviewed employees by location.

Table 1. Comparison of demographic information among the three facilities

Facility 1 Facility 2 Facility 3 Total

Number of employees available during interviews 92 

(1st, 2nd, and 

3rd shifts)

 77 

(1st and 2nd

shifts)

 66 

(1st shift)

235

Number of employees interviewed (%) 29 (32) 19 (25) 12 (18) 60 (26)

Average age in years (range) 39 

(22–67)

 38 

(22–56)

 36 

(22–53)

 38 

(22–67)

Number of males (%) 7 (24) 4 (21) 3 (25) 14 (23)

Average number of years worked at the company 

(range)

 8 

(1–26)

 8 

(1–33)

 7 

(1–18)

 8 

(1–33)

Average number of years in current job (range) 6 

(0.2–20)

 5 

(0.3–16)

 4.5 

(0.1–18)

 5 

(0.1–20)

Facility 1

We interviewed 29 employees in facility 1: 14 surfacing, 14 

finishing, and 1 former finishing employee transferred for medical 

reasons. Of the 15 current and former finishing employees, 12 

reported symptoms of WMSDs; 11 with UE and one with back 

symptoms. Some employees reported symptoms in more than one 

body location. Eight of the 12 had seen a doctor. Among the 14 

surfacing employees, 12 reported current or recent symptoms of 

WMSDs, 10 with UE and two with leg and low back symptoms. Six 

of the 12 had seen a doctor. Some employees reported symptoms 

in more than one body location. Figure 11 shows the number 

of facility 1 employees reporting symptoms of WMSDs by body 

location and job.

Among interviewed employees in facility 1, nearly three fourths in 

each area reported UE symptoms of WMSDs. Finishing employees 

reported wrist and shoulder symptoms most commonly, while 

surfacing employees reported more hand symptoms.
Page 11 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued)

Figure 11. Facility 1 employees reporting symptoms of WMSDs by body location and job.

Facility 2

We interviewed 19 employees in facility 2: 9 finishing and 10 

surfacing employees. Among the nine finishing employees, eight 

reported symptoms of WMSDs, seven with UE and one with 

back symptoms. Four had seen a doctor. Among the 10 surfacing 

employees, seven reported symptoms of WMSDs, five with UE 

and two with back symptoms. Five had seen a doctor. Figure 12 

shows the number of facility 2 employees reporting symptoms of 

WMSDs by body location and job.

Among interviewed employees in facility 2, half of surfacing and 

more than three fourths of finishing employees reported symptoms 

of UE WMSDs. Finishing employees reported wrist and shoulder 

symptoms most commonly, while surfacing employees reported 

more wrist and back symptoms.
Health Hazard Evaluation Report 2010-0114-3168 Page 12

Results

 (continued)

Figure 12. Facility 2 employees reporting symptoms of WMSDs by body location and job.

Facility 3

We interviewed 12 employees in facility 3: 4 surfacing and 

5 finishing employees, and 1 former surfacing and 2 former 

finishing employees who had been transferred to different jobs 

for medical reasons. Among the seven current or prior finishing 

employees, six reported current or recent symptoms of WMSDs; 

all were UE symptoms. Some employees reported symptoms in 

more than one body location. Three of the six had seen a doctor. 

Among the five current or past surfacing employees, two reported 

current shoulder symptoms and one had seen a doctor. Figure 13 

shows the number of facility 3 employees reporting symptoms of 

WMSDs by body location and job.

Among interviewed employees in facility 3, more than three 

fourths of finishing employees reported symptoms of UE WMSDs. 

Finishing employees reported shoulder, wrist, and forearm 

symptoms most commonly; surfacing employees reported only 

shoulder symptoms.
Page 13 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued)

Figure 13. Facility 3 employees reporting symptoms of WMSDs by body location and job.

Employees’ thoughts on causes of MSD 

symptoms

Overall, finishing and surfacing employees from all three facilities 

thought that bending for; reaching for; grabbing; and lifting trays, 

tools, and alloys caused symptoms. Finishing employees thought 

popping lenses; pushing lenses into frames; squeezing, pinching, 

and gripping tools; screwing and unscrewing; beveling and edging; 

and washing and wiping lenses were responsible for symptoms. 

Finishing employees from facilities 2 and 3 reported that overtime 

and lack of job rotation contributed to symptoms; those from 

facilities 1 and 2 thought that the job rotation and emphasis on 

stretching improved their symptoms. Surfacing employees thought 

that wiping and polishing lenses, gripping handles in fining and 

deblocking, and being on their feet a lot caused their symptoms. 

Surfacing employees from facility 3 believed that rotating job tasks 

helped lessen symptoms.
Health Hazard Evaluation Report 2010-0114-3168 Page 14

Results

 (continued) Review of Medical Records

We reviewed 19 employee medical records: 9 for facility 1 

employees, 8 for facility 2 employees, and 2 for facility 3 employees. 

Table B3 (Appendix B) compares the WMSD diagnoses; number 

and type of referrals; number that underwent surgery, physical 

therapy, and joint injections; and number put on permanent 

work restrictions among surfacing and finishing employees at 

each facility. Of the 22 WMSDs documented in the 19 employee 

records, 13 (59%) involved the wrist or wrist and hand, 4 (18%) 

involved the shoulder, 2 (9%) involved the elbow, 2 (9%) involved 

the neck or back, and 1 (4.5%) involved the hand. Three of the 19 

employees underwent surgery and three were put on permanent 

work restrictions (one of whom had undergone surgery).

OSHA Form 300 Logs of Work-Related 

Injuries and Illnesses

We reviewed OSHA Logs for years 2007–2010 and categorized 

the entries into general types of injuries and illnesses (Table B4 in 

Appendix B). We categorized entries that included sprains, strains, 

tears, pain, soreness, and carpal tunnel syndrome into a “sprains, 

strains, and pains” category. We looked at only these entries that 

were not associated with a slip, trip, or fall (i.e., those that occurred 

after bending, climbing, crawling, reaching, twisting, overexertion, 

or repetition). Sprains, strains, and pains entries accounted for 

between 40% and 91% of each facility’s yearly entries. When we 

looked at only those sprains, strains, and pains not related to slips, 

trips, or falls, 80% were UE disorders as shown in Table 2. 

Table 2: OSHA Log of sprain, strain, and pain entries not due to slips, 

trips, and falls, by body location for years 2007–2010

Year

Upper 

extremity

(%)

Back 

(%)

Lower 

extremity 

(%) 

Total 

sprains, 

strains, 

pains entries

2007 29 (74) 9 (23) 1 (3) 39

2008 33 (80) 6 (15) 2 (5) 41

2009 18 (78) 5 (22) 0 (0) 23

2010 16 (94) 0 (0) 1 (6) 17

Total 96 (80) 20 (17) 4 (3) 120
Page 15 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued) Figure 14 shows the number of UE disorder entries by body 

location and year. Wrist, shoulder, and hand disorders were most 

commonly logged (see Table B5 in Appendix B for entries by body 

location and facility).

Figure 14. OSHA 300 log entries for UE disorders for years 2007–2010.

Comparing non-fatal injury and illness rates 

between the company and U.S. industry

We used data from the company’s OSHA Logs to calculate and 

compare incidence rates of nonfatal injury and illness among the 

three facilities and the U.S. ophthalmic goods manufacturing 

industry as a whole [http://data.bls.gov/iirc/]. The incidence 

rates are for nonfatal injuries and illnesses per 100 full-time 

employees for each year. Figure 15 illustrates the incidence rates 

for total recordable cases. Figure 16 illustrates incidence rates 

for total cases involving days away from work, including days of 

restricted work activity and/or job transfer (Table B6 in Appendix 

B lists additional incidence rates). These rates can be useful for 

determining problem areas and progress in preventing work-related 

injuries and illnesses and benchmarking with similar industries. 

These rates are calculated using the following formula:

Number of injuries and illnesses × 200,000 / employee hours 

worked = incidence rate
Health Hazard Evaluation Report 2010-0114-3168 Page 16

Results

 (continued) The 200,000 hours in the formula represents the equivalent of 100 

employees working 40 hours a week, 50 weeks a year. From 2007 

through 2010, employees at facility 1 and facility 2 averaged slightly 

below 200,000 work hours per week and employees at facility 3 

averaged slightly above. Incidence rates in all categories for facility 

3 would be slightly increased and incidence rates in all categories 

for facility 2 and facility 1 would be slightly decreased if the 

formula was modified. However, we used the standard number of 

200,000 hours to allow comparison to other plants with the same 

NAICS code throughout the United States.

Figure 15. Comparison of nonfatal injury and illness incidence rates (for total recordable cases) 

for years 2007–2010; facilities 1, 2, and 3 and U.S. private industry plants with U.S. NAICS Code 

339115 (Ophthalmic goods manufacturing).

All three facility incidence rates for total recordable cases, cases 

involving job transfer or restricted work activity only, and total 

cases involving days away from work (including days of restricted 

work activity and/or job transfer) were above the U.S. NAICS rates 

for years 2007, 2008, and 2009. In 2010, these rates decreased 

to near the U.S. NAICS rates except for facility 1, which had a 

rate increase in days away from work. These trends in injuries 

and illnesses during this time period may be due to changes in 

reporting and documenting or could indicate real differences in 

injuries and illnesses.
Page 17 Health Hazard Evaluation Report 2010-0114-3168

Results

 (continued)

Figure 16. Comparison of nonfatal injury and illness incidence rates (for total cases involving 

days away from work, including days of restricted work activity and/or job transfer) for years 

2007–2010; Facilities 1, 2, and 3 and U.S. private industry plants with U.S. NAICS Code 339115 

(Ophthalmic goods manufacturing).

Discussion Employees were exposed to a combination of risk factors for UE 

WMSDs, including awkward postures (elevated shoulders and 

extended reaches), forceful exertions (lifting stacks of trays), and 

repetitive motions (twisting, reaching, wiping, assembly). Each of 

the three facilities that we visited had different equipment and 

different work organization. At the time of our visit, each facility 

had its own human resource assistant and safety and ergonomic 

committee. We found preferred practices at each of the facilities, 

and they are noted in this report. If these facilities met collectively 

to share best practices and ideas, then some hazards could be 

reduced or eliminated. Ergonomics programs have been shown 

to be cost effective, and ergonomic improvements may result in 

increased productivity and higher product quality. Promoting 

employee involvement in these efforts can enhance job satisfaction 

and increases problem-solving capabilities [NIOSH 1997a].
Health Hazard Evaluation Report 2010-0114-3168 Page 18

Discussion

 (continued) The results of the medical interviews and reviews of employee 

medical records and OSHA Logs confirmed that symptoms of 

WMSDs had occurred among surfacing and finishing employees 

and that the most commonly reported symptoms were for the 

wrist, shoulder, hand, and back. Rapid, repetitive hand motions, 

awkward postures, and forceful exertions have been associated with 

MSDs of the wrist and shoulder. Working at or above shoulder 

level also has strong associations with shoulder WMSDs. The 

combinations of work factors leading to neck and shoulder MSDs 

have been documented in previous studies [Holmstrom et al. 1992; 

NIOSH 1997b; Miranda et al. 2001]. The types of risk factors 

reported in these studies for UE and back MSDs were observed 

at these facilities and are consistent with the reported symptoms. 

Personal factors such as age, sex, smoking, physical activity, and 

strength can also influence the occurrence of MSDs [NIOSH 

1997b].

One facility had incorporated a stretching program into the work 

day. Stretching programs alone should not be used as a quick fix, 

but they can be a component of a comprehensive injury prevention 

program. An ergonomically optimized work environment, in which 

hazards are eliminated, is the best solution.

Conclusions Employees were exposed to a combination of risk factors for UE 

WMSDs, including awkward postures, forceful exertions, and 

repetitive motions. The overall rates of OSHA-reportable injuries 

and illnesses for all three facilities were above those of other 

plants in the ophthalmic goods manufacturing industry for years 

2007–2009, but did trend downward in 2010. We confirmed that 

WMSDs had occurred among finishing and surfacing employees 

from all three facilities, with wrist disorders most commonly 

reported, followed by shoulder, back, and hand disorders. 
Page 19 Health Hazard Evaluation Report 2010-0114-3168

Recommendations

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

below to create a more healthful workplace. We encourage 

the company to use an employee-management health and 

safety committee or working group, such as the ergonomics 

committee, to discuss the recommendations in this report and 

develop a comprehensive action plan that encompasses all three 

facilities. Those involved in the work can best set priorities and 

assess the feasibility of our recommendations for your specific 

situation. Our recommendations are based on the hierarchy of 

controls approach. This approach groups actions by their likely 

effectiveness in reducing or removing hazards. 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. We encourage corporate 

management to work with the management of the facilities and 

provide resources for these ergonomic improvements.

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. Many of the recommendations 

listed below were obtained from The Handbook of Ergonomic Design 

Guidelines [Humantech 2009].

1. Design all work surfaces to be within a height range of 27"–62". 

Moving the working height toward the middle of the range 

should reduce the risk for back and shoulder WMSDs.

2. Provide tables with 36" of height adjustability, especially in the 

blocking and assembly areas. This could also include sit/stand 

workstations to provide employees the ability to change their 

posture.

3. Visual display monitors, particularly in blocking, should be 

58"–71" (adjustable height) or at 66" (fixed height) for standing 

workstations and 35"–46" (adjustable height) or 46" (fixed height) 

for seated workstations. Place screens at a viewing distance of 

18"–30" (adjustable distance) or 23" (fixed distance). Monitors 

should tilt slightly downward to avoid glare. The display should 
Health Hazard Evaluation Report 2010-0114-3168 Page 20

Recommendations

 (continued) be in front of the employee, not to the side, and the top of the 

display should be at or just below the user’s eye level.

4. Parts bins (blocks, chucks, etc.) should be placed in front of the 

employee at a vertical height of 24"–70", not to the side.

5. All work, including parts retrieval or tray locations, should be 

performed within 22" of the edge of the workstation (horizontal 

work distance guideline) to eliminate extended reaches. 

Reposition work, such as the space between the employee and 

the tray takeaway in blocking, to eliminate extended reaches.

6. Provide cordless scanners or reposition the scanners or work so 

employees do not have to reach across their body to scan items.

7. Limit the number of trays stacked in all areas to no higher than 

the employee’s shoulder.

8. Place padding on the edge of the facility 2 digital blocking 

station to eliminate contact stress between the table and the 

employees’ forearms. Investigate other areas where contact 

stress may be occurring.

9. Provide a handled teapot or pitcher for employees pouring 

metal into blocking machines.

10. Provide tool bins for the most popular tools, similar to those 

seen at facility 1, in all facilities. The minimum clearance 

between levels should be 5" (from top of the bin to the bottom of 

the next shelf height). The retrieval height should be 38"–49".

11. Conveyors, especially in facility 2 between the grinding and 

polishing areas, should have a hand working height range of 

38"–49".

12. Provide pad dispensers at each facility, similar to the one at 

facility 1.

13. Modify polishing stations to eliminate placing trays on top of 

the machine. Consider adding a shelf in the empty space under 

the equipment at facility 2.

14. Provide cutouts in tables and block collection trays similar to 

those seen in facility 3 to reduce unnecessary handling of blocks.
Page 21 Health Hazard Evaluation Report 2010-0114-3168

Recommendations

 (continued) 15. Provide air-powered lens dryers, as seen in facility 3, to reduce pinch 

forces and awkward wrist postures during manual lens drying.

16. Evaluate employee exposures to fumes from the heated tinting 

solution. If necessary, provide local exhaust ventilation in the 

tinting areas.

17. Perform precision standing work, such as sanding lens edges, on 

tables that are adjustable to a hand working height of 40"–51" 

or fixed at 45".

18. Provide precision tools, such as those used for assembly, with 

the following characteristics: 0.3"–0.9" acceptable handle grip 

diameter (recommended: 0.3"–0.6"); oval or circular shape; 

2.8"–4.6" acceptable handle grip length (recommended: 3.9"); 

handle long enough so that it does not press into palm at base 

of thumb; high-friction, non-slip, or slightly etched surface or 

slightly soft composite or rubber surface.

19. Provide magnetic screwdrivers to eliminate pinch grip forces 

while holding screws during insertion.

20. Use lensometers at the optimal seated eye height, 35"–46" 

above the floor surface or 46" if fixed. The eyepiece should have 

4" or more of height adjustability. These recommendations 

were designed for microscope work, but the work is similar.

21. Provide industrial mats for employees who stand for 90% or 

more of their working hours. Mats should be ≥ 0.5" thick, 

have an optimal compressibility of 3%–4%, have beveled edges 

to minimize trip hazards, and be placed at least 8" under a 

workstation to prevent uneven standing surfaces. Mats should 

cover the entire area that employees move on while performing 

their work task and be replaced when they appear worn out or 

are damaged.

22. Implement a preventative maintenance program for machines. 

At facility 3, a blocking machine seemed to have a stuck release 

mechanism and exposed the employee to additional pinch 

forces, and a polishing machine exposed employees to vibration 

while they held the lens during polishing.
Health Hazard Evaluation Report 2010-0114-3168 Page 22

Recommendations

 (continued) 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 is necessary to ensure that control policies and 

procedures are not circumvented in the name of convenience or 

production.

1. Rotate employees through several jobs with different physical 

demands to reduce the stress on limbs and body regions. Rotate 

every 2 hours to increase job variability; use the same rotation 

pattern for all employees. 

2. Cross-train employees for different jobs so that one person does 

not work at a particular job all day, tinting in particular.

3. Limit the number of trays employees carry to reduce contact 

stress from the tray edges; the use of carts for transportation 

would eliminate this hazard. Ensure that employees are not 

carrying so many trays that their vision is blocked.

4. Evaluate the effectiveness of the implemented engineering 

and administrative controls. Develop a system for employees 

to provide information and feedback on work equipment and 

procedure modifications.

5. Schedule short breaks of 3–5 minutes every hour to allow the 

body to rest and to reduce discomfort.

6. Train employees on adjustability features of their equipment and 

workspace and ensure that they are using them.

7. Manage overtime work to avoid muscle overuse and to give time 

for muscles to rest between work shifts.

8. Train employees on MSDs and ergonomics covering specific 

operations that have been identified by NIOSH or the company 

as causing or likely to cause MSDs.
Page 23 Health Hazard Evaluation Report 2010-0114-3168

Recommendations

 (continued)

Holmstrom EB, Lindell J, Moritz U [1992]. Low back and neck/

shoulder pain in construction employees: occupational workload 

and psychosocial risk factors. Part 2: Relationship to neck and 

shoulder pain. Spine 17(6):672–677.

Humantech [2009]. The handbook of ergonomic design guidelines 

– Version 2.0. Ann Arbor, MI: Humantech, Inc.

Miranda H, Viikari-Juntura E, Martikainen R, Takala EP, 

Riihimäki H [2001]. A prospective study of work related factors 

and physical exercise as predictors of shoulder pain. Occup 

Environ Med 58(8):528–534.

NIOSH [1997a]. Elements of ergonomics programs: a primer 

based on workplace evaluations of musculoskeletal disorders. 

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

Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, (DHHS) Publication No. 97-117.

NIOSH [1997b]. Musculoskeletal disorders and workplace 

factors: a critical review of epidemiologic evidence for workrelated musculoskeletal disorders of the neck, UE, and low back. 

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

Centers for Disease Control and Prevention, National Institute 

for Occupational Safety and Health, (DHHS) Publication No. 

97-141. [http://www.cdc.gov/niosh/docs/97-141/]. Date accessed: 

November 2012.

9. Routinely analyze data from the OSHA Logs and company 

injury/illness logs to identify jobs that need intervention to 

reduce or eliminate ergonomic hazards.

10. Encourage employees to report symptons of discomfort or pain 

associated with work tasks. Early reporting allows intervention 

measures to be implemented before the effects of a job 

problem worsen.

11. Encourage injured employees to seek care from a medical 

provider with experience in occupational medicine.

References
Health Hazard Evaluation Report 2010-0114-3168 Page 24

Appendix A: Ergonomic Evaluation Criteria

Musculoskeletal disorders are those conditions that involve the nerves, tendons, muscles, and supporting 

structures of the body. They can be characterized by chronic pain and limited mobility. WMSD refers to 

(1) musculoskeletal disorders to which the work environment and the performance of work contribute 

significantly, or (2) MSDs that are made worse or longer lasting by work conditions. A substantial body 

of data provides strong evidence of an association between MSDs and certain work-related factors 

(physical, work organizational, psychosocial, individual, and sociocultural). The multifactorial nature 

of MSDs requires a discussion of individual factors and how they are associated with WMSDs. Strong 

evidence shows that working groups with high levels of static contraction, prolonged static loads, or 

extreme working postures involving the neck/shoulder muscles are at increased risk for neck/shoulder 

MSDs [NIOSH 1997]. Further strong evidence shows job tasks that require a combination of risk factors 

(highly repetitious, forceful hand/wrist exertions) increase risk for hand/wrist tendonitis [NIOSH 1997]. 

Finally, strong evidence shows that low-back disorders are associated with work-related lifting and forceful 

movements [NIOSH 1997]. A number of personal factors can also influence the response to risk factors 

for MSDs: age, sex, smoking, physical activity, strength, and body measurements. Although personal 

factors may affect an individual's susceptibility to overexertion injuries/disorders, studies conducted in 

high-risk industries show that the risk associated with personal factors is small compared to that associated 

with occupational exposures [NIOSH 1997].

In all cases, the preferred method for preventing and controlling WMSDs is to design jobs, workstations, 

tools, and other equipment to match the physiological, anatomical, and psychological characteristics and 

capabilities of the employee. Under these conditions, exposures to risk factors considered potentially 

hazardous are reduced or eliminated.

Workstation design should directly relate to the anatomical characteristics of the employee. Because a 

variety of employees may use a specific workstation, a range of work heights should be considered. On the 

basis of functional anthropometry, working heights should be within a range of 27" to no higher than 62" 

[Humantech 2009]. These heights correspond to a range of employees, between smallest (5th percentile 

female) and largest (95th percentile male).

References 

Humantech [2009]. The handbook of ergonomic design guidelines – Version 2.0. Ann Arbor, MI: 

Humantech, Inc.

NIOSH [1997]. Musculoskeletal disorders and workplace factors: a critical review of epidemiologic 

evidence for work-related musculoskeletal disorders of the neck, upper extremity, and low back. 

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

Prevention, National Institute for Occupational Safety and Health, (DHHS) Publication No. 97-141. 

[http://www.cdc.gov/niosh/docs/97-141/]. Date accessed: November 2012.
Page 25 Health Hazard Evaluation Report 2010-0114-3168

Appendix B: Tables

Table B1. Significant ergonomic hazards for surfacing tasks

Taping Blocking Grinding Tool/Pad Polish Deblock/Wash

Workstation not 

adjustable

Parts bins not 

placed in front of 

employee

Trays placed 

on top of 

machines, above 

recommended 

height

Tool rounds and 

compartments 

required 

reaches above 

and below the 

recommended 

range

Loading and 

unloading 

machines 

required 

awkward wrist 

postures

Vibration 

exposure when 

deblocking

Hand working 

height at tape 

machine is above 

fixed height 

recommendation 

of 42”

Horizontal 

reach distance 

outside the 

recommended 

range

Conveyor height 

above suggested 

hand working 

height range

No pad 

dispenser at 

each workstation, 

caused pinch 

forces

Removal of pads 

required pinch 

forces

Tape removal 

and drying 

caused pinch 

forces

Tray heights 

above shoulder 

level for some 

employees

Display monitor 

not directly in 

front of employee

Pads stored 

overhead, 

required reaches 

above the 

recommended 

height

Trays placed 

above the 

recommended 

height

No lens drier at 

many locations

Contact stress on 

edges of some 

workstations

Vibration 

exposure while 

holding the 

lens during the 

polishing process

No deblock bin at 

every workstation

Some 

workstations not 

height adjustable

Stacks of trays 

above shoulder 

level

Scanner location 

caused reaches 

in front of the 

body
Health Hazard Evaluation Report 2010-0114-3168 Page 26

Appendix B: Tables

 (continued)

Table B2. Significant ergonomic hazards for finishing tasks

Tinting Verify/Lining/Chucking Sanding Assembly

Placing the lens in the 

holder and wiping the lens 

caused pinch grips

Twisted back postures 

due to improper chair 

clearance 

Holding the lens required 

pinch grips

Tools required grip forces

No rotation to other job 

tasks

Parts bins not located in 

front of the employee

Workstation not adjustable Lensometer use and 

assembly required 

awkward neck postures

Possible exposure to tint 

fumes

Scanner location caused 

reaches in front of the 

body

Workstations not height 

adjustable

No rotation to other job 

tasks

Limited space; trays 

stacked in various 

locations that required 

extended reaches
Page 27 Health Hazard Evaluation Report 2010-0114-3168

Appendix B: Tables

 (continued)

Table B3. Results of medical record review of 19 employees by job title and facility

Finishing employees Surfacing employees Total 

(%) F1* F2† F3‡ F1 F2 F3

Employees with records reviewed 5 4 2 4 4 0 19

Referred to orthopedic 1 3 0 1 3 0 8 (42)

Referred to physical therapy 2 2 1 1 3 0 9 (47)

Underwent joint injection 1 2 0 1 1 0 5 (26)

Underwent surgery 1 1 0 0 1 0 3 (16)

Put on permanent work restrictions 0 2 0 1 0 0 3 (16)

Diagnosis/Location of WMSD

De Quervain tenosynovitis (wrist/hand) 2 1 — 1 — — 4

Carpal tunnel syndrome (wrist/hand) 1 1 — 1§ — — 3

Superior labral tear from anterior to 

posterior (shoulder)

— 2 — — — — 2

Ulnar nerve neuropathy (elbow) 1 — 1 — — — 2

Scaphoid nonunion (wrist) — — — — 1 — 1

Triangular fibrocartilage complex tear 

(wrist)

— — — 1 — — 1

Wrist pain/strain 2 — — 1 1 — 4

Shoulder pain/strain — — — — 2 — 2

Hand pain/strain — — 1 — — — 1

Neck/back strain 1 — — — 1 — 2

*Facility 1

†Facility 2

‡Facility 3

§Pending more tests
Health Hazard Evaluation Report 2010-0114-3168 Page 28

Table B4. OSHA Log of work-related injury and illness entries by facility, 2007–2010

Sprains, 

strains, pains 

not due to 

slip, trip, fall

(%)

Contusion, 

abrasion, or 

laceration

Slip, trip, fall 

injury Other Total entries

2007

F1* 12 (63) 2 3 2 19

F2† 17 (68) 2 5 1 25

F3‡ 10 (91) 1 0 0 11

2008

F1 18 (58) 5 4 4 31

F2 18 (75) 3 0 3 24

F3 5 (56) 0 3 1 9

2009

F1 7 (58) 1 4 0 12

F2 11 (85) 1 0 1 13

F3 5 (63) 1 1 1 8

2010

F1 8 (67) 3 0 1 12

F2 6 (67) 2 0 1 9

F3 3 (50) 1 1 1 6

*Facility 1

†Facility 2

‡Facility 3

Appendix B: Tables

 (continued)
Page 29 Health Hazard Evaluation Report 2010-0114-3168

Appendix B: Tables

 (continued)

Table B5. OSHA Log of sprain, strain, and pain entries not due to slips, trips, and falls, by body location and 

facility for years 2007–2010

Shoulder Wrist Hand and 

finger

Other 

upper 

extremity

Back Lower 

extremity

Total 

upper 

extremity* 

(%)

Total 

sprains, 

pains, 

strains 

entries

2007

F1† 3 3 0 2 4 0 8 (67) 12

F2‡ 4 2 4 3 3 1 13 (76) 17

F3§ 2 2 1 3 2 0 8 (80) 10

2008

F1 4 3 7 1 2 1 15 (83) 18

F2 1 7 2 4 3 1 14 (78) 18

F3 0 2 0 2 1 0 4 (80) 5

2009

F1 2 1 0 3 1 0 6 (86) 7

F2 2 4 0 1 4 0 7 (64) 11

F3 0 1 0 4 0 0 5 (100) 5

2010

F1 0 4 1 2 0 1 7 (88) 8

F2 2 3 1 0 0 0 6 (100) 6

F3 0 2 1 0 0 0 3 (100) 3

Totals 20 34 17 25 20 4 96 (80) 120

*Upper extremities include shoulder, arm, elbow, forearm, wrist, hand, and finger.

†Facility 1

‡Facility 2

§Facility 3
Health Hazard Evaluation Report 2010-0114-3168 Page 30

Appendix B: Tables

 (continued)

Table B6. Comparison of nonfatal injury and illness incidence rates for years 2007–2010; facility 1 (F1), facility 

2 (F2), and facility 3 (F3) and U.S. private industry plants with U.S. NAICS code 339115 (Ophthalmic goods 

manufacturing)

Year 2007 2008 2009 2010

Case Type U.S. Company U.S. Company U.S. Company U.S. Company

Total* 2.8

 F1: 9.8

 F2: 11.0

 F3: 9.4

3.2

F1: 11.0

F2: 11.0

F3: 5.6

2.7

F1: 5.6

F2: 5.1

F3: 5.1

3.2

F1: 5.5

F2: 3.7

F3: 3.8

Days away† 0.7

F1: 1.5

F2: 2.8

F3: 0.9

0.8

F1: 3.1

F2: 2.3

F3: 0.0

1.0

F1: 1.4

F2: 1.6

F3: 0.0

0.5

F1: 0.9

F2: 0.0

F3: 0.0

Job transfer‡ 1.0

F1: 4.1

F2: 5.5

F3: 5.1

1.2

F1: 4.8

F2: 3.7

F3: 3.8

0.7

F1: 1.9

F2: 3.1

F3: 1.9

1.3

F1: 3.7

F2: 1.2

F3: 1.9

DART§ 1.8

F1: 5.7

F2: 5.5

F3: 6.0

2.0

F1: 7.9

F2: 6.0

F3: 3.8

1.6

F1: 3.3

F2: 4.7

F3: 1.9

1.8

F1: 4.6

F2: 1.2

F3: 1.9

*Total recordable nonfatal injury and illness cases

†Cases involving days away from work

‡Cases involving job transfer or restricted work activity only

§Total cases involving Days Away from work, days of Restricted work activity, and/or job Transfer
Page 31 Health Hazard Evaluation Report 2010-0114-3168

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Health Hazard Evaluation Report 2010-0114-3168 Page 32

Ac 
Below is a recommended citation for this report:

NIOSH [2012]. Health hazard evaluation report: ergonomic evaluation of surfacing 

and finishing tasks during eyeglass manufacturing – Minnesota. By Ramsey J and 

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

for Disease Control and Prevention, National Institute for Occupational Safety and 

Health, NIOSH HETA No. 2010-0114-3168.

To receive NIOSH documents or information about 

occupational safety and health topics, contact NIOSH at:

1-800-CDC-INFO (1-800-232-4636)

TTY: 1-888-232-6348

E-mail: cdcinfo@cdc.gov

or visit the NIOSH web site at: www.cdc.gov/niosh.

For a monthly update on news at NIOSH, subscribe to 

NIOSH eNews by visiting www.cdc.gov/niosh/eNews.

Delivering on the Nation’s promise:

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through research and prevention.

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Safety and Health