Eyecare course

Common eye problems related to the use of digital screen devices

4.1 Objective: To know about the common eye problems caused by the use of digital screen devices and the definition of Computer Vision Syndrome (CVS)

By completing this chapter, you will learn the following list of topics:

Bad habits may lead to eye problems related to the use of digital screen devices
Computer Vision Syndrome (CVS)
Differences between reading digital screen and paper
Causes of dry eye
Other symptoms of CVS

4.2 Common eye problems related to the use of digital screen devices

The use of digital screen devices to view small type for prolonged periods, frequently at close working distances, has become commonplace in modern society.

Many individuals use multiple devices such as a desktop and laptop computers as well as one or more hand-held devices. These present a variety of visual demands that are significantly different from those of printed materials in terms of working distances, viewing angles and text sizes.

4.3 Bad habits may lead to eye problems related to the use of digital screen devices

There are several bad habits that may lead to the development of eye problems related to the use of digital screen devices.

5 signs for at risk behaviours

Using digital screen devices for prolonged periods (>1 hour) without rest

Rubbing eyes while using digital screen devices

Frowning and squinting while using digital screen devices

Holding digital screen devices too close
( < 16 inches or < 40 cm )

Lack of blinking

4.4 What eye problems can occur after prolonged use of digital screen devices?

Staring at your computer screen, smartphone, or other digital screen devices for long periods may cause a number of eye problems. Computer Vision Syndrome (CVS) is a term to describe these eye problems, and may affect up to 90% of computer users.

The symptoms may include asthenopia (eyestrain), headaches, dry eye, diplopia (double vision) and blurred vision after prolonged use (>1 hour) of computer or other digital screen devices.

4.5 What are the differences between reading digital screen and paper?

Digital Screen Device

Paper

Digital screen is self-illuminated.

The brightness of digital screen

is associated with visual fatigue.

Whereas paper relies on the reflection of light.

4.5 What are the differences between reading digital screen and paper?

Digital Screen Device

Paper

Objects displayed on digital screen consist of a series of pixel-based dots with decreasing brightness on their outer edges, thus making it hard for eyes to focus

Objects on paper are printed with solid ink images

Digital Screen Device Paper

Digital screen has different resolutions that affect visual fatigue and readability, whereas paper does not have this resolution issue.

4.6 What are the causes of dry eye?

Dry eye is a major symptom of CVS. It can cause both eye discomfort and blurred vision. There are three major mechanisms that may underlie the development of dry eye after prolonged use of digital screen devices.

Increased corneal exposure from viewing angle

Reduced blinking frequency

Reduced blinking amplitude

Computers are usually used with the eyes in the primary position, whereas hardcopy text is more commonly read with the eyes depressed. The higher viewing angle increases corneal exposure and tear evaporation.

People normally blink about 15 to 18 times a minute. We blink about half that often while concentrating on using computers or other digital screen devices

Incomplete blinking is commonly seen in people using digital screen devices, resulting in inadequate spreading of tears across and removal of irritants from the surface of the cornea.

Excess static electricity

Air-borne contaminants

Low ambient humidity

High forced-air heating

All of the above mechanisms contribute to the development of dry eye after prolonged use of digital screen devices. In addition, there are several environmental factors that can further increase corneal drying, such as low ambient humidity, high forced-air heating or air conditioning settings, and excess static electricity or air-borne contaminants.

4.7 What are the causes of other symptoms of CVS?

Besides dry eye, sustained accommodation and convergence for a prolonged period of time while viewing the screen of digital screen devices may also contribute to the symptoms of CVS, particularly eyestrain, double vision, and headaches. These CVS symptoms can be further aggravated by improper lighting conditions (e.g., glare or bright overhead lighting) and uncorrected refractive errors (e.g., myopia, astigmatism).

Bright lighting

Glare lighting

Myopia

Astigmatism

4.8 Summary

Congratulation! You have completed Chapter 4. You should now be able to understand the following topics.

Bad habits may lead to eye problems related to the use of digital screen devices
Computer Vision Syndrome (CVS)
Differences between reading digital screen and paper
Causes of dry eye
Other symptoms of CVS