The eyes are the most important part of the body when it comes to working at a video display. They are the sole means by which most computer users obtain information to perform their work. In order to streamline the computer work process, the design of the visual task environment and the vision of the person need to be optimized. If there is a problem with the person's vision, then they will not be able to perform their job as well as they should.
If we think of computer work like any other production process and do what is needed to improve the process efficiency, then we discover that it is cost efficient to insure that the computer worker has good vision.
The Symptoms of Vision Problems
The visual symptoms which computer workers experience are the most obvious expression of the shortcomings in the ergonomics and visual characteristics of the worker. Because of the high visual demands of the computer task and the visual shortcomings of many operators, vision problems and symptoms are very frequent among computer workers. Most studies indicate that visual symptoms occur in 75-90% of computer workers 1-3, by comparison a recent study released by NIOSH 4 showed that 22% of computer workers have musculoskeletal disorders. A large survey of optometrists 5 indicated that 10 million primary care eye examinations are annually given in this country primarily because of visual problems at computers- not a small public health issue! The most frequent visual problems reported in that survey are shown in Table 1.
The causes for the inefficiencies and the visual symptoms are a combination of individual visual problems and poor office ergonomics. The symptoms occur whenever the visual demands of the task exceed the visual abilities of the individual. Many individuals have marginal vision disorders, such as difficulties with accommodation (eye focusing), or binocular vision problems (eye coordination) which do not cause symptoms when performing less demanding visual tasks.
Workers who require bifocals or reading glasses (nearly everyone beyond the age of 40) often have special problems at computers since the optical prescription and spectacle design which they wear to meet their everyday visual needs does not work well at the computer. We have all observed the awkward position which people with bifocals adopt in order to read something above eye level- such as a book on a library shelf. This also occurs at a computer since the screen is located higher in the field of view and farther away from the eyes than the common reading tasks for which most bifocals are designed.
Dry and irritated eyes (and also contact lens problems) are common among computer workers. This is because our blink rate is significantly reduced when working at a computer. This is compounded by the fact that we are looking more straight ahead compared to desk work, therefore the eyes are open wider resulting in greater tear evaporation. The dry office environment also contributes to this problem.
There are numerous aspects of the display and the work environment which make it a more demanding visual task than others- therefore, more individuals are put beyond their threshold for experiencing symptoms. The visual symptoms can largely be resolved with proper management of the environment and by providing proper visual care for the employee 6. Key aspect of the work environment that should be investigated are listed in Table 2.
Despite the greater frequency of the vision and eye problems, more public and professional attention is usually given to the musculoskeletal disorders such as wrist (e.g., Carpal Tunnel Syndrome), neck, shoulder and back problems. One reason for this is that the vision problems are primarily symptomatic in nature and usually are gone by the next day, whereas the musculoskeletal problems generally persist for a longer period of time. However, the main reason that musculoskeletal problems are given more attention in the corporate world is that they have greater workers compensation costs associated with them.
Why should employers solve these eye and vision problems?
The eye and vision problems can largely be resolved through management of the visual environment and by providing proper eye care for employees, as will be discussed later in this paper. But, why should an employer invest resources to resolve these problems?
The primary reason is that it is good business to do so. Business executives are familiar with investing money in processes or equipment which improve efficiency. Although we typically think of assembly lines and blue collar workers when we talk about work production, we must recognize that people sitting before computer displays are a major part of work production today. Yesterday's blue collar assembly line worker has become today's computer worker. It is important that business improve the efficiency of the office worker today, just as assembly line processes were streamlined in the past.
Vision and Work Efficiency
For the sake of argument, let's put aside the humanitarian reasons for providing eye care, i.e., eliminating the vision and eye symptoms of discomfort in order to make employees feel better. Let's just consider whether it makes economic sense.
Since working at a computer is a visually intensive task, and the sense of vision is used to acquire the information need for job performance, it is reasonable to expect that improvements in the computer display or in the visual capabilities of the user will work towards improving performance efficiency. There are several studies which show that better displays or better vision result in improved efficiency.
Most of us are familiar with VGA displays- the most common display format used with DOS compatible equipment. These displays have a pixel density on the screen of approximately 75 dots/inch (DPI). It has been shown that increasing the pixel density on the screen from 75 DPI to 115 DPI results in 17.4% faster reading performance for 30 minute reading sessions 7. Likewise reading speed improvements of 4.1% to 19.9% (depending on display type) have been shown for adding a gray scale improvement of image quality 8. This argues for providing better monitors- but it also argues for providing better vision of the worker. Certainly if subjects with good vision (all study subjects had at least 20/20 vision) can obtain reading speed improvement with a better quality image, a person with poor vision will attain better performance by improving their vision.
There have been other studies into the effects of different types of visual corrections upon occupational task performance. For example, instead of wearing bifocals (for the person over 40) it is possible to be fitted with various types of contact lenses that enable a person to see clearly at distance and at near. One example is to fit one eye with the distance prescription and the other with the near prescription; another example is to wear lenses which have both the distance and near power in them. Despite the known visual compromises that occur with these types of visual corrections, these correction modalities can be successful for many patients. Even though these vision compromises are "acceptable", it has been shown that they result in 4-8% slower performance on occupational task 9-11. If these "acceptable" decreases in vision result in 4-8% productivity loss, we would expect that the more common forms of uncorrected vision, which result in larger losses of visual function, would result in even larger productivity losses.
Does Eye Care Pay for Itself?
Uncorrected vision problems in the work force create worse vision than those situations above that showed 4-19% decreases in visual task performance. Although they were laboratory studies, and the tasks were performed for durations that are considerable shorter than a full work day, it is likely that similar inefficiencies occur daily for workers with uncorrected vision disorders. We might even expect that 8 hour productivity would be more greatly reduced because of the symptoms and fatigue which accompany the vision problems.
If an employees compensation is $30,000 (including benefits), a 1% improvement in work efficiency is worth $300. Eye care can be provided for considerably less than this- and likely results in much more than a 1% increase in productivity.
Eye Care Programs for Computer Workers
Many companies already offer vision care to their employees as a benefit of employment. Even if a company offers vision care to all employees, it may not necessarily be meeting the needs of their computer-using employees. As discussed below, proper care of the computer employee requires more than a simple refraction, dilated examination of the inside of the eye, and provision of glasses. Also, many computer employees require a different pair of glasses for their computer work than that which is required for their other daily visual needs. The employee is reluctant to use their employee benefits for a pair of computer glasses, they feel that the benefits should be used to provide for their general glasses.
The backbone of any care program is the capability of the doctors who are providers for that program. For proper computer eye care, it is important that the providers understand the eye and vision problems of computer users, be able to diagnose the underlying condition and be able to implement proper care for those conditions. The most common diagnosable vision conditions which can result in compromised visual function and symptoms of discomfort are listed in Table 3. A successful managed eye care program for computer workers will have a panel of providers who are skilled at diagnosing and treating these conditions.
The American Optometric Association 12 has issued a list of recommended components of an eye examination for computer operators. In addition to those tests which are commonly part of all eye examinations, they recommend that examination of a computer patient should include: a detailed history (symptoms, nature of computer work, position and working distance of screen and other materials, and other visual characteristics of the work environment such as lighting and reflections), assessment of accommodative (eye focusing) abilities, assessment of ocular coordination, refractive determination for the required viewing distances at the computer work station, design of occupational lenses if require, and counseling regarding the visual environment at the workstation. The panel of doctors in a computer eye care program should provide these services in addition to full scope eye examinations.
Vision training for accommodative and/or binocular vision disorders should also be considered in an eye care program. Vision training is the treatment of choice in some situations- especially for convergence insufficiency. Treatment of dry eye should also be provided as part of the eye care program.
Who Pays for the Glasses?
In the interest of work efficiency, everyone who needs a visual correction should wear one. The best way to insure this is for the employer to provide the eye wear for all computer employees (or others with visually demanding jobs). However, many employers feel that employees should be responsible for providing their own general eye wear, and that it should be the employers responsibility only if the glasses are different from the general eye wear of if they would not otherwise be required. This can be accomplished, with cost savings, by establishing a list of diagnostic/treatment conditions (such as in Table 4) for which glasses will be provided. In order for glasses to be provided under the program, panel doctors would need to arrive at one of the listed diagnoses and determine that the glasses are different in prescription or design than those required for other daily visual needs.
Other Cost Controls
Costs can also be controlled by establishing limitation on the frames and spectacle lenses which are provided. Single vision and bifocal lenses are necessary program option. General progressive addition lenses should not be provided, nor even allowed as employee options, since they do not function well for computer workers. Trifocal and specially designed progressive addition lenses can be very useful for many computer workers. While it is desirable to provide these lens options, most users visual needs can be properly managed with single vision or bifocal lenses thereby resulting in cost savings. Tints and coatings provide little additional help in solving the problems that computer users have and are not necessary for the program. If only the basic lens options are to be covered, then employees should be able to pay the difference if they want more expensive options.
Another important cost control element is to provide good ergonomic assessment and corruption where indicated. It is clear that many of the eye and vision problems which computer users experience can be resolved buy evaluating and improving the visual work environment. Visual ergonomic evaluation and correction will help reduce the utilization of eye care services.
Vision screening can help to reduce over utilization by identifying those employees who are most likely to benefit from an eye examination. Professionally managed vision screening are costly and it is questionable whether the savings in utilization overcome the costs of performing the screening. Self analysis tools are available which more cost effectively enable employees to screen themselves for vision problems and also to educate them about proper use of their eyes and their computer environment.
Should You Provide Eye Care for Your Computer Workers?
Providing good vision for computer employees makes economic sense. It results in increased work efficiency and happier, more comfortable employees. It is a win-win proposition for employers to provide eye care for computer workers.
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12. American Optometric Association, 243 N. Lindbergh Blvd. St. Louis, MO. 63141