LIFESTYLE AND THE EYE
The Computer Vision Syndrome
Author : Dr.Nagaraju G
The changing scenario in recent times has made computers or visual display units (VDU) part of our routine existence. From a school going child to a corporate almost every one is using VDU either at work or at home. Numerous studies have focused upon the health hazards while working on VDUs. These have been termed as Repetitive Stress Injuries (RSI) and involve the musculoskeletal system not only due to excessive computer work but also due to faulty workstations. It has been found that almost one fourth of patients working on various forms of VDU exhibit visual complaints. It has been found to be proportional to the number of hours working in front of computers., almost 90% of patients complain of visual problems with more than 6 hours of computer work.
The usual symptoms are asthenopia or eyestrain, burning or tender eyes, redness, watering, blurred vision or difficulty in focusing, grittiness or dryness or aching sensation, double vision, feeling of heaviness, headache, tiredness, throbbing and altered color perception. Some patients feel the need to wear prescription glasses and some might require frequent change of spectacles. Systemically some patients might complain of facial rash or dermatitis, photosensitive epilepsy, fatigue, while some might complain of behavioral changes.
The eye symptoms associated with visual display units has been termed as Computer Vision Syndrome. (CVS). The eye consists of various parts which help in the perception of an object, and information of the same is conveyed to the brain through visual pathways. Eye functions like a dynamic camera and is balanced by its intrinsic and the extrinsic musculature. Cranial pathways coordinate information between the two eyes. CVS may be due to ocular factors, personal factors, workstation factors or environmental factors or a combination of the above.
Special effort is made by the eye while visualizing a VDU unlike while seeing a printed matter. The object presented to the eye itself is made up of numerous pixels which reflects upon the resolution of the monitor and by itself is not a sharp image and excess effort Asthenopia can also occur with accommodation and convergence anomalies. Hence it is more symptomatic in patients with convergence insufficiency. Since accommodative power decreases with age, appropriate modification in the workstation has to be done for persons above forty years. The eye front of the cornea is covered by a thin film of tears (inner mucin layer, central aqueous layer and outer lipid layer.) Blinking which normally is 15 to 20 times per minute helps in maintaining the ocular surface health and washing out the contaminants. Working on VDU is associated with a lowered blink rate and increased incidence of dryness and irritation of the eyes. Personal factors like general ill health, lack of nutritious food (food faddism), use of certain medications (antihistaminics), tendency for migraine, level of stress and variable working schedules all lead to symptomatic CVS
- The ideal distance from the eye to the monitor should be 25 inches or more.
- The ideal viewing area of the monitor is 6 inches (15 to 30 deg) below the horizontal eye level
- Keep the monitor top tilted 15 to 20 degrees away from the top
- Preferably work with dark letters on a light background
- Adjust brightness and contrast on the screen to avoid glare and flicker
- Attach an antiglare screen in front of the monitor as this will decrease the amount of light
- reflected from the screen
- Use a screen mounted document holder, positioned between the keyboard and minister screen almost at the same distance and height as that of the monitor.
- Adopt good posture, with feet resting flat on the ground
- Use adjustable screen and keyboards
- Use adjustable chairs with armrests
- Use table with adjustable height
- Use LCD( liquid crystal display ) screens than CRT (cathode ray tubes) screens
- Use adjustable document holder when required
- Adequately dimensioned workstation so that there is sufficient space for the operator to change
- position and vary movements
The work station should have sufficiently large and low reflectance surface The room should have medium reflectance ( pastel color) to avoid glare Lighting should be ambient: Concealed fluorescent lamps, suspended lights and windows with blinds. Indirect lighting helps to reduce glare Low humidity in air-conditioned offices aggravates symptoms especially in contact lens wearers. Avoid direct flow of air on your eyes
Regular rest breaks away from the screen are essential : follow the 20-20-20 rule ( take short breaks every 20 minutes between work for 20 seconds and look at objects at least 20 feet away) Eye exercises : closing eyes and performing clockwise and anticlockwise movements Using lubricating eye drops Nutritious diet Regular eye examination by an eye specialist Delegate tasks to prevent stress and to evoke job satisfaction
With the changing times, there is a definite change in lifestyle. The present day competitive world requires one to adapt to the digital age. With computers being an absolute necessity in everyday life one has to adapt oneself to the modern technology in such a way our body system acclimatizes to the world of VDUs References
Work and the Eye. Rachel V North VDU work and the hazards to health. A London Hazards Centre Handbook Author :