Nowadays, computer is part of the daily life of the people. Most or shall I say all particularly the IT professionals, practitioners and students spends most of their time using computers. Truly, it provides entertainment, important information such as global issues, and updates from colleagues and friends through emails and social networking sites. However, excessive usage of this technology might danger our health most especially our sense of sight.
A while ago, we had a lecture on computer vision syndrome, how to take good care of our eyes and the like. Below are the important points explained by the speaker doctor during the lecture:
by Earl John S. Jamora, O.D.
IN TODAY’S computer age, it is not surprising that computers have equaled the telephone in becoming the most indispensable piece of office equipment. Visit any office and you surely will find workers using computers.
When we use computers, our visual task demand is higher and we often experience vision problems and symptoms. There have been studies that indicate computer workers report more eye-related problems than non-computer using office workers.
In the USA, a survey of optometrists indicated that 10 million eye examinations are annually given primarily because of visual problems associated with the use of computers. This study delineated the series of symptoms which eventually became known as Computer Vision Syndrome (CVS). The American Optometric Association defines CVS as that complex of eye and vision problems related to near work which is experienced during or related to computer use. The symptoms can vary but mostly include eyestrain, headaches, blurred vision (distance and/or near), dry and irritated eyes, slow refocusing, neck and/or backache, light sensitivity and double vision.
The causes for these visual symptoms are a combination of individual visual problems, poor workplace conditions and improper work habits. Let’s tackle some of the common signs and symptoms that we might experience while using the computer.
Eyestrain is one of those vague terms that has different meanings to different people. It can be caused from such problems as focusing spasm, different vision is each eye, astigmatism, hyperopia (far-sighted), myopia (near-sighted), excess light, voluntary focusing, eye coordination difficulties, and more. In all of its manifestations – can be caused by a number of different environmental and visual condition.
Headache is another of those “discomfort” symptoms and is the primary reason most people seek an eye examination. It is also one of the most difficult maladies to diagnose and treat effectively.
Visual headache most often occurs toward the front of the head (there are a few exceptions to this), occurs most often toward the middle or end of the day, does not appear upon awakening, often occur in a different pattern or weekends than during the week, can occur on one side of the head more than the other, and other more general symptoms.
Computer workers most likely get tension-type headache. It can be caused by many forms of stress, including anxiety and depression; numerous eye conditions, including astigmatism and hyperopia; improper workplace conditions, including glare, poor lighting, and improper workstations setup. If all obvious factors have been considered, medical management is in order, often starting with a complete eye examination.
An image that is not focused accurately will appear blurred. Blurred vision symptoms can result from refractive error (e.g. hyperopia, myopia, astigmatism), improper prescription lenses, presbyopia (age-related focusing problem) or other focusing disorders. Considering the working environment, blurred images can also arise from a dirty screen, poor viewing angle, reflected glare or a poor quality or defective monitor. All of these factors should be considered when this symptom occurs.
DRY AND IRRITATED EYES
Our eyes are covered with tears which maintain moisture for normal eye function. The tears also help to maintain the proper oxygen balance of the external eye structures and keep the optical properties of the visual system maintained. The normal tear layer is cleaned off and refreshed by the blinking action of the eyelids.
The blinking reflex is one of the fastest reflexes in the body and is present at birth. However, our blink rate varies with different activities – faster when we are very active, slowly when we are sedate or concentrating. Research has shown that the blink rate of computer workers dropped very significantly during work at a computer compared to before and after work. Possible explanation for the decreased blink rate include concentration on the task or a relatively limited range of eye movement. The size of the eye opening is related to the direction of gaze – as we gaze higher, the eyes open wider. The amount of evaporation roughly relates to eye opening, the higher gaze angle when viewing a computer screen results is faster tear loss. It is also likely that the higher gaze angle results in a greater percentage of blinks that are incomplete.
NECK AND/OR BACKACHE
In many office situations the vision of a worker is compromised and they must adapt their posture to ease the strain on the visual system. For example, if an older worker is using glasses (single vision) which are designed for a 16″ viewing distance, they must lean in toward a screen which may be 20″ to 25″ or more away in order to clear the image. If the same worker is using traditional bifocals, which are designed to see the near object in the lower visual field, they must tilt their head backward and lean forward to put the physical problem which can be easily remedied with the proper glasses.
Discomfort glare is largely caused by the large disparities in brightness in the field of view. It is much more desirable to eliminate bright source of light from the field of view and strive to obtain a relatively even distribution of luminances. A person is at greater risk to experience discomfort glare when the source is brighter and when it is closer to the point of attention.
Workers are also at risk for discomfort glare if they use a dark background display screen-resulting in a greater brightness disparity between the task and other object in the room. Other sources of large brightness differences at the computer workstation include white paper on the desk, light colored desk surfaces, desk lamps directed toward the eyes, or which illuminate the desk are too highly. Using multicoated lenses help reduce glare.
When we do computer work, our eye muscle move our eyes closer to maintain the alignment of the image on both eyes. If we fail to do this, double vision occurs, Double vision is a very uncomfortable and unacceptable condition for our visual system. We would rather “suppress” or turn off the image of one eye rather than experience the double images. Double vision is a serious symptom and can be caused by several factors. A complete eye examination is indicated if this symptom occurs.
Computer Vision Syndrome is a by product of excessive viewing of computer screens without regard to practical visual hygiene. By just using some common sense and education about the visual system, the symptoms of CVS can be diminished or eliminated.