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 Table of Contents  
Year : 2016  |  Volume : 1  |  Issue : 2  |  Page : 48-63

Ergonomics and work-related musculoskeletal disorders in ophthalmic practice

Department of Ophthalmology, College of Medicine, Al Imam Mohammad Ibn Saud Islamic University, Riyadh, Saudi Arabia

Date of Submission30-May-2016
Date of Acceptance21-Sep-2016
Date of Web Publication21-Aug-2017

Correspondence Address:
Waleed Abdulaziz Alrashed
Al Imam Mohammad Ibn Saud Islamic University, P. O. Box: 305077, Riyadh 11361
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijas.ijas_24_16

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Purpose: To increase the awareness of eye health care providers about Work related musculoskeletal disorders and proper ergonomics.
Method: Literatures review of all aspect of work related musculoskeletal disorders and ergonomics pertaining to heath care in general and particularly to eye care providers.
Results: Work related Musculoskeletal disorders (WRMSD's) among health care workers including Physicians, nurses, dental hygienist, and Custodial worker are well known. In the last two decades WRMSD's and related problems have being substantiated by different studies on the above mention groups, and in particular Ophthalmologists along with dentists and some surgical subspecialties (Laparoscope surgeons and Ear, Nose, and Throat surgeons). It was attributed to the specific nature of the job which requires prolonged awkward position and repetition. In these series of four articles will try to highlight the most important areas where health care providers especially the ophthalmologist should take care and aware of to prevent or at least reduce the WRMSD's. These areas involve: in the work and outside of work activities and include: (A) Clinic: The proper way of conducting slit lamp examination with or without the use of different lenses. How to perform direct and indirect ophthalmoscopes with the least stressful way to cervical and lumbar spine (will be covered in part 2 of this review). (B) Work station and office: How to set in proper way and how to select ergonomic and comfortable chair, tables, mouse, keyboard, screen and foot rest (will be covered in part 2 of this review). Also computer vision syndrome (will be discussed in part 4 of this review). (C) Operating room: Tips in how to adjust surgeon chair, microscope, and operating table to achieve the best ergonomic position. Also hints in the proper way of selecting and using surgical loupes (will be covered in part 2 of this review). (D) Outside the Hospital: Advises in the proper way of using portable visual display devices (smart phones and tablets etc…) along with hints on how to sit while driving and how to sleep with the least stress to the back and neck(will be covered in part 3 of this review).
Conclusion: Adopting a healthy neutral posture and along with the comply of basic ergonomics principles in different areas of ophthalmic works early in the medical career (i.e. Residency) along with maintaining regular muscles stretches and exercise will reduce those unwanted Musculoskeletal squeals and hopefully leading to prolonged and productive healthy career life.

Keywords: Cumulative trauma disorders, doctor safety, ergonomics, ophthalmology, work-related musculoskeletal disorders

How to cite this article:
Alrashed WA. Ergonomics and work-related musculoskeletal disorders in ophthalmic practice. Imam J Appl Sci 2016;1:48-63

How to cite this URL:
Alrashed WA. Ergonomics and work-related musculoskeletal disorders in ophthalmic practice. Imam J Appl Sci [serial online] 2016 [cited 2023 May 28];1:48-63. Available from:

  Introduction Top

Medical practitioners, as well as other professions, are associated with occupational hazards. The risks and the consequences are varied from profession to profession, on the basis of the very situations of the practice. Many occupation groups in the health-care sector, including nurses, dental hygienists, and custodial workers, carry an increased risk of developing back pain, due to the amount of physical activity required on a regular basis.[1] Injury rates among hospital workers have been estimated to be nearly twice that of other service industries.[2]

An emerging literature is also available documenting work-related musculoskeletal disorders (WRMSDs) among different medical specialties and mainly surgery. In dentistry, it has been shown that 54% of the studied dental care workers complained of neck pain and 73% complained of back pain.[3] Nearly one-third of all dentists who retire early are forced to do so due to a musculoskeletal disorder (MSD).[4]

A study about ophthalmic plastic surgeons showed that 72% reported pain associated with operating and 9% reported stopping operating due to pain or spine injury.[5]

Again 72% of 325 ear-nose-throat surgeons reported back or neck pain or both; 53% attributed this directly to their practice of surgery.[5]

In the recent studies, up to 80% of surgeons across multiple specialties, including general surgery, otorhinolaryngology, plastic surgery, orthopedics, and trauma surgery, reported experiencing musculoskeletal pain while performing operative procedures and 40% reported pain of sufficient intensity, necessitating rest breaks during surgery.[6]

Ophthalmology profession is demanding specialties for sharing the hazards and risks common to all surgery, and also having their own occupational hazardous exposures, such as laser radiation, use of slit lamp, operating microscope, and conducting direct and indirect ophthalmoscopies for examination, diagnosis, and treatment.[7] There is just a handful of reports about the magnitude of this problem in ophthalmology; for example, data from a survey of vitreoretinal surgeons, reported at the 2004 meeting of the American Society of Retina Specialists by Uday R. Desai et al. found that, among more than 500 respondents, 55% reported both back and neck pain and 7% required surgery. Only 15% reported experiencing no symptoms at all.[8] In a 2005 survey of American ophthalmologists, 52% of the 697 respondents reported neck, upper body, or lower back symptoms in the prior month of survey, with 15% limiting their work as a result of these symptoms.[9] Among 130 American ophthalmic plastic surgeons responding to a 2010 survey, 72.5% reported pain associated with operating; 9 surgeons (7%) reported having to give up operating as a result.[5] A 1994 survey of 325 ophthalmologists in the United Kingdom found that 54% of respondents had significant attacks of back pain, with those longest in the field having more frequent back pain. Nine surgeons (4.5%) needed surgery for back pain.[1]

  Summary Top

  • The reported prevalence of all musculoskeletal symptoms in ophthalmic practice ranged from 46% to 94%[6]
  • The prevalence of neck symptoms ranged from 32% to 69%
  • The prevalence of upper extremities/shoulder symptoms ranged from 11% to 32%.
  • The prevalence of low back symptoms ranged from 26% to 79%.
  • 5%–7% required surgery.
  • Seven percentage of all ophthalmologists have to give up surgery at some point as a result of WRMSD's
  • Up to 15% of all ophthalmologists were somehow limited in their work because of WRMSD's
  • <15% of all ophthalmologists have no signs or symptoms of WRMSD's.

The magnitude and the cost of work-related musculoskeletal disorders in general

MSDs are among the most common occupational injuries and illness. Many epidemiologic studies report associations between physical risk factors (e.g., forceful exertion, static or awkward posture, and repetitive motion) and musculoskeletal symptoms among all occupations.

According to the United States Bureau of Labor Statistics latest release in 2015,[10] the MSDs, commonly known as ergonomic injuries, account for 32% of all work place injuries and illnesses requiring days away from work in 2014.

In the USA, there were 365,000 MSDs in all ownerships (state and local government and private industry) with an incident rate of 34 cases/10,000 full-time workers.

Workers who sustained MSDs required a medium of 13 days to recuperate before returning to work, compared with 9 days for all types of cases. Also, WRMSDs are the number one cause of lost time in the work place representing approximately 50% of all lost time claims and accounting for more than 60% of annual cost.

Among the top ten occupations for MSDs are nursing assistant and registered nurses. In fact, MSD cases account for 54% of the total cases that occurred to nursing assistants in 2014.

According to the Occupation Safety and Health Administration (OSHA),[11] the average cost per incidence of an MSD is estimated to be $12,000, which includes lost work with full wages, replacement wages, lost productivity, and medical treatment (not including surgery). If surgery is required, the average cost increases to $43,000 per incidence according to the American Society of Orthopedic Surgeons.

MSDs each year account for more than $15–20 billion in workers' compensation cost, and total direct costs add up to as much as $50–60 billion annually in the USA (almost $1 billion per week). Also, according to the OSHA, benefits of implementing an effective ergonomics program will result in $9 billion saved each year by the U.S. industry.[12]

  Work-Related Musculoskeletal Disorders Top


WRMSDs are a group of disorders of the muscles, tendons, ligaments, nerves, vessels, and joints resulting from long-term, cumulative, repeated wear and tear in different body parts.[8]


WRMSDs include lower back pain (LBP) (secondary to lumber disc prolapsed), carpal tunnel syndrome (CTS), neck pain (secondary to cervical disc prolapsed), tendonitis, and others.[8]

Other names

The reader may find these acronyms in the literatures and all are interchangeable

  • Cumulative trauma disorders [13]
  • Repetitive trauma disorders
  • Repetitive strain injuries
  • Repeated motion injuries
  • Overuse syndromes
  • In this review, WRMSDs will be used all over discussion.

Risk factors

Common risk factors to work-related musculoskeletal disorders

  • Repetition [13],[14]
  • Static loading or sustained exertions
  • Awkward postures
  • Mechanical contact stress
  • Force.

The United States National Institute of Occupational Safety and Health [14] found strong evidence that static loads, extreme working postures, and high levels of static contraction increase the occurrence of MSDs in the neck. In addition, high cognitive load and mental stress also contribute to MSDs. In the ophthalmic field, the major risk factors most commonly blamed are extreme or awkward postures, excessive static loading or exertion, and repetition. If the arms are unsupported, that will put more static force on the upper back, neck, and shoulders (cervicobrachial region). In addition, ophthalmic surgeons obliged to work with fine instruments, in doing so, they are exerting sustained fine gripping forces on the instrument trying to keep it stable for significant time while working on the eye.[8]


Performing the same or similar motions repeatedly can result in trauma to the joints and surrounding tissues. Without giving enough time for rest and recovery, repetition can lead to injury.[13],[14]

It has been shown in different studies that the main predictor of surgeon's work-related musculoskeletal symptoms was patient volume. Seeing more than 100 patients per week, performing ≥4 surgeries, and ≥6 laser per week were associated with increased neck, upper extremities, or lower back symptoms.[9],[15]


  • Typing at the keyboard for prolonged period of time [16]
  • Moving and clicking the mouse extensively and repeatedly
  • Writing by hand
  • The use of slit-lamp biomicroscope (which often limited adjustability of the ocular position and chair/table height).

Static loading or sustained exertions

Static loading is one of the risk factors known to increase the risk of WRMSD in the field of ophthalmology.[13],[14] It occurs when a muscle holds part of the body in a single position for a long period of time. This lack of movement reduces circulation and causes muscle tension, which can contribute to or aggravate already existing WRMSDs. Sustained exertions are a type of static loading where force is applied continuously for long periods of time, typically occur with prolonged visual focus often in postures dictated by limited adjustability of surgical and clinical instrument.[13],[14]


  • Keeping still while reading from the monitor
  • Sitting for long periods of time
  • Performing surgery under the microscope with prolonged visual focus and precision gripping of instrument [1],[6]
  • Indirect laser treatment
  • Working with surgical loupes.

Awkward postures

For each joint in the body, there is specific range of motion if exceeded repeatedly and for prolonged periods of time may lead to WRMSDs.[13],[14] Postures that force the joints into positions where they are more likely to become injured are termed awkward postures [Table 1].
Table 1: Range of motion for selected parts of body

Click here to view


  • Typing with bent wrists
  • Leaning over to type in data from papers lying flat on the desktop
  • Slouching or leaning forward in the chair [13]
  • Performing gonioscopy/laser treatment under slit lamp with awkward upper extremities postures
  • Awkward postures while performing indirect ophthalmoscopy (for diagnosis or laser treatment)
  • Operating under a microscope in an awkward posture (stooping over patient)[1]
  • Using poorly designed surgical loupes, forcing the awkward posture.

Mechanical contact stress

A hard or sharp surface or object pressing into the soft tissues, tendons, nerves, and blood vessels can cause damage that over time can result in serious injury.[14] This damage is termed mechanical contact stress.[13]


  • Resting wrists on the desk edge while typing or using the mouse [13]
  • Leaning the elbows on hard chair armrests or work surfaces; for example, resting the elbow directly on the slit-lamp table with no cushion support, especially during gonioscopy or during laser slit-lamp treatment [13]
  • Resting the hands on unpadded chin rest at the operating table.


Many ophthalmology office tasks require mild-to-moderate amount of force to be applied by very small muscles, if sustained, it may cause fatigue, swelling, muscle strains, and ligament strains.[13],[14]


  • Grasping thick file folders or manuals [13]
  • Stapling or stamping by hand [13]
  • Use of freer elevator to reflect the periosteum during dacryocystorhinostomy
  • Use of bone punch to create osteotomy in dacryocystorhinostomy
  • Injecting highly viscous material manually
  • Exerting excessive gripping forces while handling fine instruments, trying to keep them stable during work
  • Helping in lifting patient off/on the examination chair or surgical table.[8]

Using electromyography, photography, and computer modeling, “risky work patterns” in ophthalmic practice have been explored and it is clear that the ophthalmologist encounters if not all, most of these factors. Most ophthalmologists work or operate in prolonged static postures without head and arm support, and sometimes while wearing indirect ophthalmoscope or surgical loupes. In many instances, positioning during surgery and other clinical activities can be awkward, and by its nature, is associated with high cognitive load and stress.[5]

All the above circumstances clearly explain why ophthalmic care providers are at risk for developing WRMSDs. It is due to their exposure to ergonomic hazards, such as tasks that demand a high level of visual, manipulative, and reach requirements. In addition, it is due to the reduced access to the patient, the adoption of awkward working postures for prolonged period of times, and limited freedom to reposition an instrument or the microscope. Adding to these, the requirement to focus the microscope while simultaneously manipulating foot pedals with both feet and using both hands at the same time, all of which are known to highly influence work postures, especially for the head, neck, arms, hands, and lower back.[2],[6] None of these injuries will occur over a short period of time. They are the result of cumulative insults accumulated over years of practice.

Hence, the ultimate goal should be to identify these risky activities and modify them while the practicing ophthalmologist is still early in his career. Young ophthalmologists need to know and reminded that bad habits will catch up with them.

Additional risk factors

  • Hand–arm vibration, such as holding a power tool [13],[14]
  • Work organization (psychosocial) factors include.[14]
    • Overtime
    • Incentive pay
    • Lack of control over work place
    • Deadlines
    • Close supervision
    • Conflicting responsibilities
    • Boring, mundane work.[13]

Incentive work has the potential of increasing repetitions and the risk of WRMSDs. If the work place is out of the control of your employees or if there are deadlines, pauses to rest overstressed muscle groups may not be possible. While the pace of incentive is under your employees control, their desire for financial gain may cause them to work through pain, to skip breaks, and to work faster, all of which create more repetitions. This may result in a greater number of WRMSDs and/or more serious WRMSDs.[13],[14]

Ideas in improving work organization (psychosocial) factors to help decrease work-related musculoskeletal disorders

Job rotation

Periodic (every 2 h) job rotation to tasks with lower repetition, or to tasks where different muscle groups are used, may not only provide your employees with variety and increased job satisfaction but also may decrease their risk of WRMSDs.[13]

Staffing and scheduling

In some cases, adding temporary staff rather than requiring employees to work overtime at a repetitive task may have long-term financial advantages due to reduced injury costs.[13] Alternating between difficult and light cases and giving more treatment time for the difficult cases is advisable.

Rest breaks (recovery pauses and stretch)

Breaks at mid-morning, lunch, and mid-afternoon have long been a part of work schedules and are an important part of allowing employees time to recover from the demands, both mental and physical, of their jobs. Employees should be encouraged to take these breaks away from their work environment and use the opportunity to walk around and give their hands and eyes a rest.[13],[17]

Taking frequent, shorter breaks is preferable to taking longer, fewer breaks.

Factors outside of work

Not all musculoskeletal risk factors are work related, poor physical condition (lack of exercise),[13],[18] smoking, older age, and certain preexisted medical conditions such as rheumatoid arthritis, diabetes, obesity, or pregnancy are all examples of factors outside work environment.

Signs and Symptoms of work-related musculoskeletal disorders

Common signs and symptoms of WRMSDs include a decreased range of motion, decreased gripping strength or inability to hold objects, swelling, stiffness or cramping, numbness, and tingling,[18] occasionally it may cause redness, loss of color, and in more extreme cases, loss of function or deformity in part of the body involved.[8]

How common work-related musculoskeletal disorders in ophthalmic practice why?

Routine ophthalmic practice involves excessive musculoskeletal workload in the neck, shoulder, upper extremities, and lower lumbar region. Performance of tasks which have a high level of “visual,” “manipulative,” and “reach” demands on head neck and arms results in increased muscular tension in the cervicobrachial muscle nerve complexes.[16]

The contributing role of the eye care physician's physical work environment, in both clinic and procedural settings, to the development of MSDs or musculoskeletal symptoms must be taken seriously. Eye care physicians in those studies identified several job factors that contributed to musculoskeletal symptoms to a greater extent than other nonsurgical medical specialties, for example, family medicine physicians. These factors included performing the same task repeatedly, working in awkward/cramped positions, working in the same position for long periods, and bending/twisting the back and neck repeatedly. Occupational tasks specific to the eye care physician group and performed frequently in the office environment include the use of the slit-lamp biomicroscope (which often with limited adjustability of the oculars and controls), indirect ophthalmoscope, and use of microscope and surgical loupes. These devices and tasks may excessively expose eye care physicians to nonneutral postures and muscular exertions of neck, shoulders, trunk, and distal upper extremities. Procedures performed in the operating room or with lasers demand similar positional requirements, but also frequently involve prolonged, static postures. Prolonged visual focus is also required, often in postures dictated by limited adjustability of surgical and clinical instrument.[6]

“Risky work patterns” in ophthalmic practice have been identified. It include but not limited to the following:[1],[2],[8],[16]

  1. Computer use/typing
  2. Slit-lamp biomicroscopy (examination/laser treatment)
  3. Direct and indirect ophthalmoscopy
  4. Operating microscope use
  5. Surgical loupes' use.

Ergonomics definitions

Ergonomics is derived from the Greek “ergon” (work) and “nomos” (laws) to denote the science of work.

Ergonomics is the scientific study of human work. It applies information about human behavior, physical and mental abilities, and limitations and other characteristics to the design of tools, machines, tasks, jobs, and environments for productive, safe, comfortable, and effective human use.[13],[19] Simply, ergonomics is the science of fitting jobs to the person who work them (not fitting people to job). Effective ergonomic design coupled with good posture can reduce employee injuries and increase job safety, satisfaction, and productivity.[18] In addition of applying ergonomics, the ophthalmic practitioners should be educated and encourage practicing preventive muscle stretching and exercise to safeguard against injuries.[17]

“It's a lot simpler to choose the right equipment than to adapt the wrong equipment!”– Alan Hedge, USA [20]“It's a lot simpler to change a line when designing than to modify already made instrument or machine!”– Waleed Al-Rashed, Saudi Arabia (the author of this article).

Benefits of ergonomics

Ergonomics reduces the risk of injury by adapting the work to fit the person instead of forcing the person to adapt to the work.[13] While ergonomic improvements to the work are primarily used to create a safer and more healthful work environment, the institute may experience other benefits:[13]

  • Prevent or at least reduce the work-related injuries and WRMSDs
  • Increased energy levels and productivity: It is common for ergonomic improvements to increase productivity by 10%–15%. In fact, studies have shown up to 25% increase in output at computer workstations when using ergonomic furniture, while concurrently improving employee well-being [19]
  • Decreased job stress
  • Improved employee morale and decreased employee turnover
    • Ergonomics help to spread the “I care” message to all levels of the organization
  • Decreased number of sick days (absenteeism) and reduce turnover
    • When people are comfortable at their works, they are less likely to take time off from work or leave the institution because of discomfort
  • Decrease the mistakes (including medical errors) and improved quality of both work and life and job satisfaction
  • Increased career longevity.[17]

Applications of ergonomics

Ergonomics has been applied long time ago in areas such as defense, nuclear reactors, and the aerospace industry before its application in the medical field. Currently, more than twenty technical subgroups within the Human Factors and Ergonomics Society indicate the range of applications for ergonomics. In fact, within the last 100 years, human factors engineering continues to be successfully applied in the fields of health care, aging, information technology, product design, manufacturing, transportation (automotive), in training, and virtual environments, among others.

Ergonomics in workstation includes computer use/typing.

Neutral posture at your workstation

The possibility of sitting in a chair for many hours a day can be fatiguing, so it is essential that work chairs should be ergonomic and healthy. Experts agree that chair is perhaps the single most important component of a healthy working environment.

As we all know from the basic anatomy, the spine has five natural curves when viewed from the side: the upper cervical kyphosis, the lower cervical lordosis, thoracic kyphosis, lumbar lordosis, and sacral kyphosis. Except in the sacrum, the spinal curves are all mobile and therefore influenced by their neighboring curves.[17],[21]

As we know physiologically, every part of your body has a neutral posture. This is the position in which the least amount of stress is placed on the muscles, nerves, vessels, ligaments, tendons, and joints. For example, to attain neutral-seated posture, you should have a slight lordotic curve in the low back, shoulders over hips. Neutral head posture is ears-over-shoulder when viewed from the side, so in summary, ear, shoulder, and hip all are aligned.[17] Elbows should be relaxed at the sides and as close as possible to the trunk (adducted) and forearms approximately parallel with the floor [Figure 1]. Likewise, neutral standing posture is ear, shoulder, hip, and ankle in alignment when viewed from the side [Figure 2]. In this standing posture, the pelvis is at angle that optimally supports and balances the spine and minimizes muscular exertion.[13]
Figure 1: Neutral-seated posture, lower back well supported. Ear, shoulder, and hip are all aligned. The thigh sloping downward the feet flat on the floor

Click here to view
Figure 2: Neutral standing postures ear, shoulder, hip, and ankle all are aligned

Click here to view

However, this ideal seating posture is generally cannot be maintained all the time while operating under the microscope or during slit-lamp examination. In addition, one postural guideline will not be comfortable for all tasks and body characteristics. Therefore, it is helpful to know the recommended postural working ranges for each area of the body. Operators can use these guidelines to find a posture that best suits their body character and then operate within these postural limits as much as possible.[17]

Recommended safe postural working ranges

Ophthalmologists should do their best for a head posture of no more than 10° forward, the absolute maximum being 25°. The hip angle should be at or >90° to decrease pressure on the internal organs, especially for obese people and pregnant women, and to help maintain lumbar lordosis. Recommended hip angles range from 90° to 105° with a tilting seat pan to 125° with a saddle style stool. The thighs should be sloping downward, with the feet flat on the floor or foot rest. You should feel weight evenly distributed on three areas: through each foot and through your buttock. Reaching forward with your arms from the shoulders should not be more than 20° and arm abduction should not be more than 25° (elbow or armrests are recommended).

[Table 1] In office or when operating under microscope, forearms should be parallel to the floor or sloping about 10° upward or downward.[17]

Forward head posture is a prime contributing factor to WRMSDs, a problem frequently seen among ophthalmologists due to years of poor posture involving holding the neck and head in an unbalanced forward position to gain better visibility during slit-lamp examination, indirect ophthalmoscopy, and microscopic procedures.

The general guidelines to achieve neutral posture while seated

  1. Keep your head level tilted slightly downward. Place your work in front of you so that you are looking straight ahead
  2. Sit with your shoulder relaxed, not elevated hunched or rotated forward
  3. Keep your elbows close to your sides (avoid “winged” elbows) and bent at about a 90° angle, not extended out in front of your body
  4. Use the chair's backrest to support your lower back, or lumbar curve
  5. Sit your entire upper body upright or leaning slightly back
  6. Keep your wrists straight while you work, not bent up, down or to the side
  7. Sit with your knees at the same level or slightly below the level of your hips. There should be no pressure points along the backs of your thighs or at the backs of your knees
  8. Place your feet slightly out in front of your knees and make sure they are comfortably supported, either by the floor of by a footrest.[13]

The importance of changing postures frequently

Ergonomists often say “The next position is the best position ”

Our bodies were not made to stay in any position for hours. Our bodies work best with motion and frequent position change.[21] Sitting still for long periods of time is not healthy, regardless of how good your posture may be. You should make small adjustments to your posture about every 15 min, by changing the height of your chair slightly, or leaning back further into the backrest. Larger changes in postures are also important; stand up and stretch or walk around for one two minutes every hour.[13]

Some workstations are programmed to move from sitting to standing with the single press of a button while others save money by the use of a simple hand crank.

Types of ergonomic seating postures

“90°” posture (traditional sitting posture)

For most of the last century, ergonomics widely assumed that we should sit upright “cubist posture” (with 90° knee, torso, and elbow positions) aimed to prevent ergonomic risk.

This position is biomechanically correct, but it can fatigue your back muscles over time (static loading or sustained exertions). Fatigue can lead to slouching, even on a chair with lumbar support.[13],[21]

In addition, it decreases the natural curvature of the lower back (lordosis) by about 30% and this will lead to increase in the static load on the discs and may decrease the circulation in the lower extremities.[21],[22] So, in summary, this sitting posture looks nice but it is just not comfortable.

Reclining posture

Lean back 10°–20° into the chair's backrest and put your feet out in front of you to open up the angle at your hips and knees.[13],[21] This helps relax your back muscles and promotes blood circulation. Leaning back too far, however, can result in an awkward neck posture when trying to keep your head upright.

Declining (forward) tilt posture

Raise the height of your chair's seat a few inches and tilt the front of chair pan downward about 10°–30° depending on the type of chair (regular vs. Balans vs. Saddle style). This will open up your hip-torso angle and allow supporting some of your weight using your legs rather than having it all rest on your hips and the backs of your thighs.[13],[21] Another advantage of this kind of seat is reinstating the normal pelvic forward inclination which helps in restoring the physiological lumbar lordosis. It has been shown that a minimum of 110° thigh-torso angles is needed to reinstate the natural curve of the lumbar spine.[22]

Benefits of a sloping seat

It decreases the load on your lower back and minimizes the risk for LBP.

Also, sitting with your thighs in a downward slope increases the activity of your lower leg muscles. As a result, return blood flow from the lower legs is improved, and there is less pooling of the blood and pain in the lower legs by the end of the workday. Consequently, in the long run, it can reduce the likelihood of varicose vein development.[21],[23] In addition, a sloping seat pan makes rising from the chair easier.[23]

Disadvantages of a sloping chair

The major disadvantage reported is the feeling that you have to constantly counteract gravity to avoid sliding off the chair.[23] A minor disadvantage frequently quoted, of having the clothing ride up the seated person legs, which, can be overcome by chair properly designed with nonslip textured material.[23] The seated person may not find this posture comfortable if they have knee or foot problems.

Standing posture

Standing provides the biggest change in posture and is a good alternative to prolonged sitting. Good neutral standing position should revert (reinstate) pelvis to normal position (rotate forward) and lower lumbar spine to go back to its normal lordotic curvature. It can be fatiguing, however, have a counter height chair available at standing workstations, or use a height adjustable sit/stand workstation. Also, propping one foot up on a low footrest occasionally helps shift weight and reduces the discomfort.[13]

Standing while working also increases energy and decreases mental fatigue, thereby increasing productivity by getting more done in shorter periods of time; in addition, a sit-to-stand desk will allow better sharing of data, presentations, and graphs all from one normal computer.

Chair specification

The chair is the most important part of your office workstation. It has to fit you and suit the tasks that you do. One style of chair may not suit every worker. For example, the “average” size chair is designed to fit the average male and may not suit other users. The lower few paragraphs illustrate the most important chair specification to consider when purchasing office chairs.

Pneumatic or hydraulic control

Almost all chairs today have pneumatic or hydraulic controls for easy, smooth adjustment of the stool height (15–18 inches). The control levers under the seat pan should be prominent, so they make adjustment easier and quicker.[17]

Tilting or saddle-style seat

The presence of a feature allowing a slight incline forward of the seat pan (5° to 15°) helps facilitates the lumbar curve in the low back. Tilting seats and saddle-style stools may also enable closer positioning to the patient by opening the hip angle to >90.°[17]

Seat depth

A standard seat pan depth is 16 inches and should support most of your thigh. When seated all the way back on the seat and in contact with the backseat, the operator should leave 2–3 inches between the front edge of the chair seat and the back of the upper leg.[17]

Seat width

The seat should be wide enough to support the operator entirely (19 inches). Keep in mind that stools with wider and deeper seat pans require more room around the patient chair for maneuverability.[17]

Textured seat and contour

The seat's material should be textured to prevent slipping when the seat is inclined forward and has seamless upholstery. It is also recommended to get padded and sloping waterfall edge of the chair (this refers to the flowing downward of the front edge of the seat pan to reduce pressure on the back of the knee).[17]

Lumbar support

The backrest is the convex portion that supports your lower back curve and needs to be adjustable up and down (7–11 inches) to provide adequate support. A backrest is recommended with the feature of backward and forward adjustability to mold according to the body size and the amount of lordosis required.[17] A backrest with good lumbar support helps maintain neutral spinal curves when sitting. This is an especially important feature with a nontilting seat pan, which tends to flatten the low back curve.[17]

Due to the neutral positioning of the pelvis with a saddle stool, a backrest is generally not necessary in such type of stool.[17]

Five-caster base on rollers

At least five casters are essential for stability and therefore safety. It is very important to choose low height wheelbases (low profile casters), so if necessary, it can slide under the footrest of the patient's examination chair during slit-lamp examination (helping the examiner to be closer to the patient). Also, wide wheelbases are more stable but can be less maneuverable and prevent close positioning to the patient if they hit the patient's chair base. Make sure the roller type is appropriate for the operating room floor (carpet vs. hard floor). The wrong rollers can make it difficult to move the chair around the patient.[17]


The arms represent approximately 10% of the total body weight, which can result in considerable exertion in the muscles of the upper back, shoulders, and neck if not supported appropriately. Studies support the use of armrests in the prevention of neck, back, and shoulder pain.[17]

Armrest should be padded with soft material and highly adjustable (especially the height) to provide support to the operator in a neutral working posture. Designs vary widely, from fixed, adjustable armrests, to swiveling and telescoping armrests, which move with the operator.[17] The recommended length of armrest is 10–12 inches and the distance between armrests is 19 inches and the suggested arm rest height is in the range of 7.5–10 inches.[24]

Slit-lamp ergonomics

Remember that patient is in the slit lamp 3–6 min once or twice a year, but, you are there 5 days a week for your career life.[17]

Practical clinical tips and hints to adapt during slit-lamp examination

Initially, sit upright with the neck in a neutral position, accordingly adjust the seat and the slit-lamp at the beginning of the day, and try not to change either of these regardless of the patient's height and body habitus. In other words, the only thing that moves is the patient's chair and chin rest, not the slit-lamp height or the physician's seat height.[25]

The correct posture to be adopted at the slit lamp

  1. Position the patient and slit lamp in such a way that your back stays straight and in neutral posture, i.e., avoid the flexed/kyphotic (slumped) posture [16] [Figure 3]
    Figure 3: Flexed /kyphotic posture (slumped) with forward head and shoulder posture

    Click here to view
  2. Use seats with height and anterior tilt features to accommodate sitting postures
  3. Tilt the pelvis anteriorly to maintain lumbar lordosis
  4. Your back should be supported by the chair back
  5. Relax your shoulder and do not flex or extend your neck [Figure 4]
    Figure 4: Neutral sitting posture with maintenance of ideal spinal curvatures (upper cervical kyphosis and lower cervical lordosis)

    Click here to view
  6. To reduce the risk of rotator cuff tendonitis and shoulder impingement syndrome, avoid unsupported upper extremities (abduction and extension of the arm) [Figure 5]
    Figure 5: Unsupportive upper extremity and ulnar deviation with wrist extension during slit-lamp biomicroscopy may predispose to rotator cuff tendonitis and carpal tunnel syndrome, respectively

    Click here to view
  7. Your arm and elbow should be supported by an elbow rest made up of soft material (foam-padded material or viscoelastic surface), this will decrease the risk of ulnar neuropathy by reducing the contact stress at the cubital tunnel [Figure 6]
    Figure 6: No wrist deviation, no or minimal forearm pronation. The elbow is resting upon a cushioned surface to give support to upper extremity

    Click here to view
  8. Using a standard pincer grip or pulp pinch grip increases the pressure in the carpal tunnel. Therefore, use a pencil grip whenever possible
  9. Avoid pronating your hand or forearm during gonioscopy. Avoid flexion or extension of the wrist
  10. Relax your muscles and stretch your arms between patients and procedures.[2],[16]

It has been noticed that new slit-lamp tables in the current ophthalmic offices are 5–6 inches longer (deeper) than they used to be. Using them to examine the patient requires a significant amount of hunching.[25] To overcome this problem, assemble the slit-lamp biomicroscopy unit on the adjustable table to be closer to the examiner than to the patient by moving the rails of the axle rollers toward the physician side, by doing so, the physician will not be forced to lean forward and extend and flex his neck during eye slit-lamp examinations.[8],[26]

Consider purchasing newly designed angled (tilted) oculars which help keeping the neck and head maintain neutral position.[8]

It is preferable to choose low height wheelbases (low profile casters), so it can slide under the footrest of the patient's examination chair during slit-lamp examination and hence the examiner be closer to the patient.

Also, for appropriate patients, consider the use of a foam back wedge (placed between patient's back and back rest), so it helps to decrease how far a patient is from the front of the seat edge.

Operating room ergonomics

Remember that patient is in the operating room once or twice for only 30–60 min in his/her life, but, you are there once at least every week for your career life.[17]

Complying with the following recommendations will help reducing work-related musculoskeletal disorders

  1. Adjust seat, table, and microscope to accommodate a neutral posture (take enough time to properly position yourself, it will not take more than 15 s to do so). The ideal sitting posture includes an anteriorly tilted pelvis, with maintenance of lumbar lordosis, neutral thoracic kyphosis, lower cervical lordosis, and upper cervical kyphosis.[16] To achieve this, you have to choose forward tilt posture; achieved by raising the height of your chair's seat a few inches and tilt the front of chair pan downward about 10°. This will open up your hip-torso angle and allow supporting some of your weight using your legs rather than having it all rest on your hips and the backs of your thighs.[13] Another advantage of this kind of seat is reinstating the normal pelvic foreword inclination which helps in restoring the physiological lumbar lordosis. We need a minimum of 110° thigh-torso angles to reinstate the natural curve of the lumbar spine.[22] Maintaining this physiological spine curves reduces disc pressure, helping reduce low-back pain, and the downward slope of the thighs usually enables closer positioning to the patient during examination and surgery. Sitting with the seat pan tilted forward 5° to 15° opens the hip angle to about 110°, while a saddle-style stool increases the angle to about 125° or more. Using a saddle stool moves your pelvis toward its most neutral-seated position (very close to a standing posture), which requires the least muscular effort to maintain the spinal curves. This is one reason the saddle stool does not usually require a backrest
  2. Use seats with padded lumbar support and adjustable height and also front-back adjustability features to help maintaining a neutral pelvic and spine position
  3. Keep the lumbar spine in contact with the back support
  4. Rest elbows at sides (do not elevate/abduct the arms [2]) on padded armrests if available or rest wrists on a padded support to provide forearm support and reduce contact stress on the elbows, hands, and wrists
  5. Position your wrist rest so that, when you are holding heavy hand pieces, your wrist is not flexed
  6. Avoid the slight spine tilt due to different height and inclination profiles of the foot pedals (surgeons performing cataract surgery use two foot pedals, one for the microscope and the other one for the phacoemulsification machine), by raising the microscope foot pedal slightly with towels, so the feet to be at the similar height
  7. Arrange cords (microscope and phacoemulsification machine pedals) in a manner that will not conflict with maneuvering the chair
  8. Try to be as relax as possible while gripping instruments for prolonged periods
  9. Periodically pause and stretch upper extremities with at least a finger flexor and a finger fan stretch
  10. When possible, or at least in between cases, pause, stand, and perform upper body and back stretches
  11. Reduce the duration of awkward postures involved in some complicated surgeries by staging procedures. Be aware that problems can occur while performing fine precise movements while using the pincer grip, prolonged seated posture, and holding fine instruments for prolonged periods
  12. Avoid exerting a lot of force when handling stiff cord (i.e., cryoprobes). Hoses on all delivery systems should be lightweight and flexible to avoid muscular strain.

Practical tips and hints to be adapted during microscopic ophthalmic surgeries

Sit in a chair and make yourself comfortable in neutral position. Then, bring the microscope into position and wheel the stretcher and the patient into position. This will set up a more stable ergonomic platform.[25]

Make sure that the patient's head is at the top of the bed or even hanging over the edge by half an inch. This allows you as a surgeon to sit up straight and avoid having to bend forward at the waist and it will force your neck backward to look through the scope. Also, insure keeping the binoculars in a neutral position. All of us have different torso lengths, so for some people, the oculars will be positioned at a 90° angle whereas other people will look down into the microscope.[25] Invest by purchasing movable oculars for the surgical microscope. “Eyepieces that can move in and out and up and down” should help the surgeon avoid assuming an awkward neck position.[8],[27]

The angle between the binoculars and the barrel of the surgical microscope – the part that points down toward the patient's eye – used to be fixed, so surgeons, especially tall surgeons, often slumped over to use the microscope.[8] Have been moved 20° toward the surgeon, allowing him/her to stand straight [Figure 7].[28]
Figure 7: Sitting posture in the operating room with the use of microscope: (a) When the barrel of microscope set vertically, the operator will adjust by back and neck flexion. (b) Tilting the barrel of the microscope around 20° will solve the neck and back flexion

Click here to view

Another way to avoid issues with bending over a microscope is to use one of the new television systems, with the surgeon looking at a screen using special three-dimensional (3D) glasses instead of through the microscope (True Vision's stereoscopic high-definition visualization system).[8],[28] With this view, system surgeon can perform 3D virtual surgery [15] without the necessity to sit at the microscope, holding a rigid position to operate.[28]

Design and selection of equipment, instruments, and disposables

The general guide to design, so the small woman can reach, and the large man can fit.

Although ergonomic sizing has been incorporated into objects almost of all office equipment, it has yet to be achieved with respect to surgical instruments. Surgical gloves are produced in eight sizes, from 5.5 to 9.0, in increments of 0.5, with all surgeons knowing their exact glove size. Yet even with such well-documented and well-understood differences in hand size, surgical instruments are produced mostly in a single size (products are often designed for the “average” individual – a person who does not exist). Everyone is a deviation from the average. Resolve for such equipment issues would benefit from studies grounded in anthropometric data, characterizing the population of ophthalmic surgeons in a particular country in terms of body size and proportion.[29]

Hence, the design of instruments or equipment depends on the average is not enough, medical manufacturing companies should be encouraged to design on the basis to accommodate the central 90% of users (from the 5th percentile of the females to the 95th percentile of males).


Gloves are one of the most overlooked ergonomic items. Gloves should not be too tight across the palm or too constricting at the wrist. Improperly fitted gloves may cause CTS. Ambidextrous gloves (can fit either right or left) are generally molded with the hand in a flat (neutral) position and were originally designed for brief and quick medical examinations, whereas hand-specific fitted gloves are molded with the hand in a more dynamic working position. It has been shown that, when ambidextrous gloves are used for longer procedures, the operator's hand must exert almost one-third more force than fitted gloves. The finger length should be adequate to allow for comfortable finger movement.

A general guideline for fitting gloves is that they should be loose across the back of the hand and palm to aid comfort and circulation and snug in the fingers to improve touch feeling.[17]

Diameter of instrument

Larger instrument handle diameters reduce muscle load and pinch force. However, handle diameters >10 mm (about 3/8 inch) have been shown to have no additional advantage. Alternating between handle diameter sizes may help prevent CTS symptoms. When selecting instruments, try to include large diameters as well as other sizes, but avoid the very narrow diameter size of 6 mm.[17]

Weight of instrument

The lighter the better, therefore, look for hollow or resin handles (15 g or less). They help reduce muscle workload and pinch force.[17]

Texture, shape, and color of the instrument handles

Round, knurled, and grooved (textured) handled-surfaces may also help decrease forceful pinch/pincer grips.[17] In addition, color coding may make instrument identification easier.

Go powered instrument

Use automatic headpieces instead of manual instruments as much as possible. Compared to manual removal of bone in dacryocystorhinostomy, use of powered diamond cutting burr headpiece requires less force applied to the work and a less forceful precision grip.[14] From a preventive perspective, powered instrumentation should be used periodically over the course of the day to reduce muscle workload and provide rest to the intrinsic hand muscles.[17]

Use self-retained retractors and instruments with self-locking mechanism

Retraction of soft tissue with self-retained retractors can alleviate the need for sustained, manual retraction and may help prevent pain syndromes in the hand, arm, and shoulder. Also, the use of self-locking mechanism forceps and other instrument will help solving problem related to sustained pinch grip.

Minor/major operative room scheduling

The goal is to provide sufficient recovery time for the physician and his/her staff to avoid chronic muscular fatigue by the following:

  • Increase treatment time for more difficult patients
  • Vary procedures within the same scheduled day
  • Alternate difficult and light cases within a flexible scheduling system (difficult procedures scheduled back-to-back do not provide your body with sufficient relaxation time).

Direct ophthalmoscope ergonomics

First make sure the patient eye height is at your eye level height, and then ask the patient to come closer to you for examination while you are sitting or standing [Figure 8].
Figure 8: Direct ophthalmoscopy (a) Awkward examiner posture (b) Patient is asked to come closer to the examiner while he is maintaining neutral spine position

Click here to view

Indirect ophthalmoscope ergonomics

Ophthalmoscopy is necessary to see into the patient's fundus and sometimes deliver laser treatment to the patient's eyes in different angles. This can result in forcing the doctor to twist his/her neck and body into different awkward positions [Figure 9]a.[8]
Figure 9: Indirect ophthalmoscopy positions: (a) Excessive neck flexion secondary to low patient position. (b) Less neck flexion with elevation of patient chair

Click here to view

Ergonomic recommendations to be followed while conducting indirect ophthalmoscopy

  • Chose a light weight indirect ophthalmoscope (ideal weight for an indirect ophthalmoscope is zero) to decrease the compressive and shear load on the discs of your neck
  • Do not bend over and try to keep neck and back in neutral position as much as you can by elevating the patient's chair, so the examiner is at eye level with the patient head. The patient's chair can be then reclined to 45° and the patient's head can be tilted in various directions to see out the periphery of the retina [Figure 9]b[25]
  • Limit neck flexion to <25° and sideways bending to <10°
  • Use the head of the patient to support your hand while performing sclera depression.[16]

Loupes (scopes) ergonomics

Loupes are the most popular type of magnification used in some subspecialties in ophthalmology such as oculoplastic and pediatric ophthalmology. The goals are to provide the required magnification and at the same time maintaining the neutral neck posture. While none of these loupe systems provide perfectly neutral head posture, well-designed loupes should enable a working posture of <25°s of head flexion and <15 head extension posture.

In general, loupes used in ophthalmology range in strength from 2X to 5X and working distance from 14 to 22 inches.[17] Two basic styles are on the market: through the lens (fixed mounted) and front lens mount (flip-ups).[17]

Through-the-lens loupes

These loupes are engraved into the lens, and it provides wider field of view since scope is closer to the eye. They do not get knocked out of adjustment. Declination angle is preset and not adjustable. It is slightly lighter weight than flip-ups. One disadvantage is changes in eyeglasses prescription lenses require return to manufacturer for modification.[17]

Flip-up loupes

These loupes are mounted in front of the lens, generally on a hinge mechanism. It provides better declination angle for optimal head posture. This type of loupe can be easily flipped up when not in use, and eye glasses prescription can be easily changed by a local optician.[17] They can get knocked out of preset adjustment and tend to be slightly heavier.

The most important ergonomic factors to consider when purchasing loupes are declination angle, working distance, scope position in relation to the pupil, amount of magnification, weight, and lighting needs.[17]

Declination angle

The angle that the eyes are inclined downward toward the work is the declination angle [Figure 10]. This angle should be steep enough to help the user attain a comfortable working position with minimal forward head posture (<25°).[17]
Figure 10: Loupe declination angles: (a) Loupes with a poor declined angle <30° (b) loupes with steep declined angle >30°

Click here to view

Scope position

The lower the scope in relation to the operator pupil, the better the working posture. Therefore, choosing large frame with vertical slide feature will allow the lowest placement of the scope [Figure 11].
Figure 11: A vertical slide feature and large frame insure that the loupes sit low enough in relation to the pupil to obtain maximum declination angle

Click here to view

Working distance

The working distance is the distance from the eye to the best focusing working area. If the working distance is too short, it can result in excessive neck flexion or hunching. Working distances will vary from shorter operators (14 inches or less) to extreme long working distances for very tall operators (more than 20 inches) [Figure 12].[17]
Figure 12: Sitting position with loupes in use (a) Loupes with a good declination angle will allow the operator to work with minimal forward head posture. (b) Loupes with bad declination angle and short working distance will force the user to adopt slouching position (c-shaped posture)

Click here to view

Organizational intervention to decrease the risk of WRMSDs

Development or creation of multidimensional program to raise the awareness of the organization commitment toward addressing root causes of WRMSDs (ergonomics risks) in each specific areas of the hospital or institution by:

  • A series of workshops regarding WRMSDs to build the culture of safety and well-being of the workers and the patients (take care of yourself, so you can take care of your patients)
  • Development of ergonomic training program provided for:
    1. Management: To understand and support the program with the necessary resources
    2. All members of ergonomics team: They interpret health and job analysis data, which allow them to make informed decision regarding management of the program
    3. Supervisors and workers: They recognize and report WRMSD's risk factors in different situations and so they can report it early and cooperate with interventions
  • Creation of ergonomic team and empower them with resources and authority, part of their tasks are:
    1. Conduct work place inspections regarding WRMSDs
    2. Identify problem areas and help implement suitable interventions
    3. Evaluate the effectiveness of the implemented interventions
  • Development of manual about basic ergonomics and its risk factors to be distributed to all current staff and to be handled to any newly appointed one.

Please take care of your patients and yourself.

This review article will be in three parts. Each part will include:

Part one:

  • Abstract
  • Introduction
  • The magnitude and the cost of WRMSDs in general.
  • WRMSD:
    • Definition
    • Risk factors
    • Ideas in improving work organization (psychosocial) factors to help decrease WRMSDs
    • Signs and symptoms of WRMSDs
    • How common WRMSDs in ophthalmology and why?

Part two:


  • Definition
  • Benefits of ergonomics
  • Applications of ergonomics
  • Ergonomic in work station (compute use)
    • Neutral posture at work station
      • Recommended safe postural working ranges.
    • The importance of changing postures frequently
    • Types of ergonomic seating postures
      • 90° posture
      • Reclining posture
      • Declining posture.
    • Standing postures
    • Chair specification.
  • Ophthalmic application of ergonomic in different situations and locations
    • Slit-lamp ergonomics
    • Operating room ergonomics
      • Design and selection of equipment, instruments, and disposables
      • Minor/major operative room scheduling.
    • Direct ophthalmoscope ergonomics
    • Indirect ophthalmoscope ergonomics
    • Loupes ergonomics
      • Through-the-lens loupe
      • Flip-up loupes.
  • Organizational intervention to decrease the risk of WRMSDs.

Part three

  • Ergonomics of driving
  • Ergonomics of sleeping
  • Ergonomics of video display terminal and portable digital display device (notebooks, tablets, smart phones, e-books readers … etc.)
  • Conclusion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]

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