INTRODUCTION

Life in 21^st century has become easier and more comfortable as compared to olden times; a major contributor to this development is the use of modern technologies. Among these is the burgeoning hi-tech silicon world of computers. We can not imagine today's life without computers. Nowadays, computers have become a part of education, business, e-trading, socializing, chatting and recreation. More and more people today are spending a major share of their day playing with the keyboard and mouse.  With this increase in the use of computer, certain health problems are also on rise. These include computer vision syndrome, carpel tunnel syndrome, repetitive strain injury, backache etc. Among these, the commonest is the computer vision syndrome or CVS as it is also known.

DEFINITION
Computer vision syndrome (CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time. Some symptoms of CVS include headaches, blurred vision, neck pain, fatigue, eye strain, dry, irritated eyes, and difficulty refocusing the eyes. These symptoms can be further aggravated by improper lighting conditions (ie. bright overhead lighting or glare) or air moving past the eyes (e.g. overhead vents, direct air from a fan). CVS has not been proven to cause any permanent damage to the eye.

PATHOPHYSIOLOGY
CVS is caused by decreased blinking reflex while working long hours focusing on computer screens. The normal blink rate in human eyes is 16-20 per minute. Studies have shown the blink rate to decrease to as low as 6-8 blinks/minute for persons working on the computer screen. This leads to dry eyes. Additionally, the near focusing effort required for such long hours puts strain on ciliary muscles of the eye. This induces symptoms of asthenopia and leads to a feeling of tiredness in the eyes after long hours of work. Some patients present with inability to properly focus on near objects after a short duration. This can be seen in people aged around 30-40 yrs of age, leading to a decrease in the accommodative focusing mechanisms of the eye. This can be a setting for early presbyopia.

AETIOLOGY

Some conditions which have been found to be related to eye and vision discomfort after prolonged usage of computers include:

1. Failure to blink while working.
2. Low humidity in environment
3. Improper brightness and contrast of computer screen.
4. Improper lighting of computer room or if the glare from windows or nearby lights is too bright.
5. Improper monitor height, incorrect distance from eyes to screen and other postural errors.
6. Too small computer typeface.
7. Cathode ray tube (CRT) screen users are more prone than LCD screen users.
8. Decreased amplitude, improper accommodation.
9. Higher incidence has been found in people with binocular vision dysfunction viz. strabismus, those with uncorrected presbyopia, uncorrected astigmatism.
10. Use of certain drugs like antihypertensive, antihistamines, antidepressants, anticholinergics  which alter the pupil's response to light and depth of focus.

SIGNS/SYMPTOMS

1. Eyestrain
2. Dry eye
3. Blurred vision
4. Double vision
5. Color distortion
6. Sensitivity to light
7. Headache
8. Backache, neck pain
9. Shoulder pain, wrist soreness

PREVENTIVE MEASURES

In Selection Of Computer:

1. It is better to use  LCD monitor than old tube style monitors ,because LCD has anti reflective  surface while CRT monitors cause flicker of images  that increases if the refresh rate of monitors is less than 75 hertz(HZ).
2. Select computer screens with the highest resolution. Resolution is related to 'dot pitch' of display and lower dot pitch have sharper images. Choose display with dot pitch of 28mm.
3. Select large display for desktop computers, that have a  screen size of at least 19 inches

While Working on Computer:

1. Text size and color should be optimized for maximum comfort.
2. Excessive bright light from outside sunlight and harsh interior lighting cause eyestrain. So exterior light should be decreased by closing drapes shades while interior lighting should be controlled by using lower intensity bulbs, tubes etc.
3. Use task lamp that shines only on your paper but not in your eye or monitor. Glare on finished surface and wall causes eye irritation. To avoid it install an anti glare screen on your monitor.
4. Keep your screen free from dust, smudges.
5. Workstation and chair should be at correct height. Computer screen should be 20 to 24 itches away from your eyes. It should not be too high or too low. It should also be 10 to 15 degree below your eyes. Document holder should be next to your computer so; you do not have to constantly change your eye focus.
6. Maintain good posture, back should be straight and shoulder back posture breaks are important to avoid overuse of one group of muscle.
7. Avoid desk which has sharp edge, which increase pressure on wrists and cause soreness.
8. Mouse should not be kept close to body it should be kept directly infront of shoulder.
9. To avoid eye tiring   follow 20-20-20 rules i.e., look away beyond 20 feet at every 20 minutes and blink 20 times.
10. To avoid neck, shoulder, back pain, take break, stand up, move about and stretch your arms, legs, back, neck and shoulder.

HOMEOPATHIC TREATMENT

Computer Vision Syndrome is an occupational disease, so the best way to treat the complaints is to avoid the maintaining cause i.e. overuse of computers alongwith taking homeopathic medicines for the presenting complaints. Some of the medicines which have been found to be highly efficacious in the discomfort are:

ARGENTIUM NIT--Complaints due to overwork. Muscles around eyes become tired. Patient feels better by closing eye or pressure, aggravated by being overheated. A good remedy for restoring power of weakened cilliary muscles.

ARNICA--Constant close focus causes sore feeling in eyes. Fatigue due to overwork, patient desires open eyes and feels dizzy on closing them. Backache due to overexertion.

RUTA GRAVE--Chief remedy for eyestrain due to overuse of eye muscles. Patient has watery eyes, oversensitiveness to light; stiffness and pain ultimately leading to headache. Patient feels pressure behind eyeball. Difficulty in focussing eyes.

CONIUM MAC--Artificial light or overwork causes eyestrain, photophobia. Improper night vision, patient has foreign body sensation, aggravation in night, amelioration by pressure and dark room. Seeing black spot in front of eyes due to fatigue. Headache with lancinating pain on vertex , semi lateral.

NATRUM MUR--Continuous reading or school work leads to weak bruised feeling in the eye, stiffness of muscle around eyeball. Eyelid feels heavy and lastly person complains of headache. Letters on screen board seem to run together. Constant computer typing causes numbness and tingling in the fingers. Backache relieved by putting hard things under back.

THUJA--Good remedy for cramps in fingers. Tips of fingers tough ended, feel dead.

CROCUS SATIVA--Patient complains of constant blinking after eyestrain and reading.

EUPHRASIA-- After continuous eyework watery eyes, burning and swelling of eyelids. Sticky mucous on cornea with much blinking.

KALMIA LATIFOLIA -- Stiffness of eyelids aggravated by moving eyes. Vision weak or impaired with neuralgic pain in face and teeth. Joint or muscle  stiffness. Shifting pain from place to place .

XANTHINAM-- Good remedy for backache. Patient has pain in coccyx area, can not sit on hard surface and has to put soft pillow below while sitting.

PILOCARPUS-- Good remedy for eyestrain whatever may be the cause. Slightest use causes tired feeling in eyes. Nausea and vertigo after use of eyes. White spots seem to appear before eye.

SENEGA OFFICINALIS-This medicine acts on Rectus superior muscle of eye. Patient has sensation as if eyeballs are too large for orbit. Hypersensitivity to light. Headache with pressure and weakness of eye. Pain in temples, bursting pain on forehead with double vision, dry eye, ameliorated by bending head backward.