Computer users and dry eye
Andreea CHIVA, biochemist Ph D
Computer is the most fascinating invention of the 20th century. Intensively used, it can lead to some ocular and musculoskeletal disorders.
25-93 % of computer users reported ocular discomfort (dry eye and Computer Vision Syndrome), while only 22% reported musculoskeletal disorders (neck, back and shoulder problems and/or carpal tunnel syndrome).
The main cause of ocular discomfort in computer users is the blink rate decreasing from 16-20 times/min (that is normal) to 6-8 times/min. What is happening, in fact?
When we are blinking, the ocular surface is covered by the tear film (an aqueous solution in which are dissolved many biochemical compounds, such as proteins, lipids, carbohydrates, enzymes, immunoglobulins) that play an important role in eye nutrition and lubrication. At each blinking, the tear film is renewed for a good function of the eye. Decreasing in blinking rate lead to a long exposure of ocular surface to environement, tears excessive evaporation and symptoms of dry eye: irritation, ocular fatigue, blurred vision, foreign body sensation.
Computer vision syndrome and dry eye associated with computer use are often ignored, the visit to ophthalmologist being done only when symptoms become bothersome and when, unfortunately, the biochemical changes at tear level has been occured.
For these reasons, the prevention and early diagnosis of ocular complications in computer users are very important.
Prevention of dry eye and ocular complications can be made by satisfying some ergonomic rules:
-the screen should be placed to the line vision
-“20-20-20” rule that means every 20 minutes, focus the eyes on an object 20 feet (6 meters) away 20 seconds
Early diagnosis consists of regular eye examination in association with some tests for estimation of tear secretion rate (Schirmer test) as well as electrophoresis of tear proteins in HYRYS -HYDRASYS SEBIA France system.
The simultaneous electrophoretic analysis of several proteins with clinical value (lactoferrin, lysozyme, albumin) using a small quantity of tears (20 μl) that are collected by a non invasive procedure allows the identification of early biochemical changes generating ocular complications and the therapeutic efficiency.
The amplitude of biochemical changes is correlated with ocular discomfort severity and the time of computer use. Levels of lactoferrin <18 % and more than 3 hours spent using the screen are associated with severe complications that requiring an immediate treatment.
All these considerations recommend the electrophoresis of tear proteins as an important test for early diagnosis of ocular complications in computer users, in particular in the risk groups: contact lens and glasses wearers or users of oral contraceptives, antiallergic or antiglaucoma drugs, as well as smokers and air conditioning users.