How can a Computer cause Dryness in the Eyes?

Introduction
Tear and tear film - A normal tear film coats the front surface of the eye and protects from the environmental contaminants and cleansing and flushing harmful chemicals.

Tear film provides lubrication and wetting of the front surface of the eye by a blink and makes the surface of the eye smooth and clear tear film consist of 3 layers (inside to the outside) - these are mucus, watery and oily layer. Inner or mucus layer enable tear to ‘stick’ to the surface of the eye. Middle or aqueous layer accounts for the most of the tear film, cleanses the eye and washes away foreign particles or irritants. This layer provides oxygen and various nutrients to the eye surface. The outer or oily layer is very thin and floats on the surface of tear film, prevents evaporation of tear film.

• Eyelids are curtains of the eye and also important in maintaining tear film. Eyelids functions as a wiper - spread tears over the surface of the eye.

What is Computer Vision Syndrome?
As computers became a part of our everyday life, most of people are experiencing a variety of eye-related symptoms related to computer use. These ocular complaints occurring as a result of operating a computer either singly or in combination - are collectively referred as ‘Computer Vision Syndrome’ (CVS).

Eye related complaints on computer use:
It is estimated that approximately 90% of the peoples are using computers everyday for more than 3 hours - may experience eye strain, tired eyes, burning sensation, irritation, redness, blur in vision, intermittent blurriness, watery eyes, double vision (ghost images), dryness, grittiness or heaviness, after an extended period of time.

Causes for Dry Eye on Computer Uses
• Age: Tear production normally decreases with age. Although dry eye can occur at any age in both gender.

• Environmental factor: The eye surface is very sensitive to drying and chemical imbalance from environment factors (pollution, office hazards such as dry air, ventilation fans, airborne paper dust, laser and photocopy toner).

• Reduced blink rate: Most of the individuals normally blink approximately 12 - 15 times per minute. A reduced blink rate contributes a poor quality of the tear film on the eye surface. The blink rate at the computer is significantly less than the normal.

• Increased exposure: The reading of text on paper is normally performed while looking downwards. This result – eyelids cover a substantial portion of the front surface of the eye (minimizing the evaporation of tears).

• Systemic disease: Various systemic disease like Sj√∂gren syndrome, rheumatoid arthritis lead to a decrease tear secretion and cause dry eyes.

• Medication: There are several medication contributing to ocular drying.

• Contact lens: Contact lens comfort is highly dependent on the lubrication of the eye. Office personnel wearing contact lenses are found to be more likely to suffer a higher severity of ocular discomfort. The contact lens surface should skate along the eye and eye surfaces with minimal resistance. If the ocular surface is dry, the lenses dry and adhere to the upper eyelid during the blink. This “friction effect” from dry eye produces the discomfort.

• Ocular condition: The most common disorder, blepharitis (dandruff like flakes in eye lashes), an inflammation of eyelids affecting the eyelid glands. The lack of an adequate lipid layer contributes to rapid evaporation of tears (water component of the tear film) causing discomfort.

• Cosmetics: Oil based cosmetics applied on the inner surface of eyelid margins can block the opening of the oil secreting glands.

• Ocular surgeries: Correction of refractive error by LASIK or PRK procedure causes decrease in tear production and sometime leads dryness.