Computer Vision Syndrome
Dr Sujatha Mohan
Rajan Eye Care Hospital, Chennai-17
It is a well known fact that computers have become indispensable in the workplace. Professionals spend increasing amounts of time sitting at their computer work- stations and take less and less breaks. With increasing demand for more productivity and tight deadlines workers are exposed to more hours of work in front of computers.
CVS is defined as that complex of eye and vision problems related to near work, which is experienced during or related to computer use.
The Computer population in India is 20 Million plus and 80% of them (16 Million) have discomfort due to CVS. The prevalence of eye symptoms among computer users ranges from 25-93% as reported by various investigators.The combination of fixed and constrained body postures, work overload and unsuitable workstations can lead to eye and health problems. The most common complaints among computer users are aches and pains in the shoulder, forearm, wrist, hand, back and neck and eyestrain.
RSI [Repetitive Strain Injury] is a blanket term that is used to describe many different types of work-related disorders and injuries to the upper limbs as a result of muscular overload. This overload is usually caused by repetitive movements and/or overuse of specific muscle groups (categorised as static load), especially if the joints adopt extreme positions. RSI is not a new disease and also affects people who do
not work at a keyboard.
This article is intended to prevent health problems among computer users. Clearly a large percentage of computer workers experience eye symptoms and subsequently seek eye care. .
These symptoms are often a result of a combination of three factors:
- Workplace conditions;
- Working habits;
- Visual condition.
A person is regarded as a keyboard operator if he or she spends more than two hours per twenty-four hour period working at a computer.
The computer workstation
The chair: when seated, the weight on the lower back is one and a half to two times more than while standing. A good chair must accommodate all body sizes and must be adjustable in the following areas:
Height of the seat: The feet should rest comfortably on the floor, at 90 degree angle between upper and lower legs .In this position, the upper legs are virtually horizontal.
Depth of the seat: The clearance between the front edge of the seat and the back of the knee must fit a clenched fist.
Backrest: The backrest must support the area from the upper ridge of the pelvis to the shoulder blades. The curve in the backrest must support the hollow in the lower back. An adjustable tilt is desirable.
An Ideal Computer Work Station
What are the primary factors that determine discomfort for computer users?
- Nature of the task
- Length of time spent at the computer
- Reduced rate of blinking
Lack of coordination between the design of the workstation and the design of the glasses or contact lenses used for the task. The average rate of blinking is 12 to 15 times per minute. This is frequently reduced during intensive tasks leading to visual fatigue and dry eyes. Therefore, reading from a screen reduces blinking, which in turn, leads to discomfort.
Here are some examples of situations that usually increase user discomfort:
- Intense tasks such as games
- Tasks with few breaks from the screen
- Tasks, which require constant looking from copy to screen such as data entry
- Detailed tasks such as desktop publishing or Computer Assisted Design (CAD)
Tips for avoiding CVS
- Eye level placement of screens causes eyes to be wide open causing faster drying.
- Eye level screens are too high for most bifocal wearers unless they have specially designed glasses for this task.
- Many glasses exacerbate the restriction of movement, which is a consequence of most computer tasks causing neck, shoulder, and arm problem.
- Avoid excessive bright screen
- Use
- Moderate background ambient illumination ( Illumination from screen = light from the document )
