As optometrists, concerned parents often ask us about the effects of screen use on their child’s eyes. In order to dispel some myths about screen time, we decided to put together this useful fact sheet.
Blue light is a high-energy visible light and has a short wave length. It is called so because it is on the violet-blue band of the spectrum.
Blue light is naturally present in sunlight but is also something we can see from screens such as TVs, computers, smartphones and tablets.
The Association of Optometrists (2017) state that “there is currently no scientific evidence that blue light causes damage to the eyes. However, there is evidence to suggest that carrying out near tasks, involving looking at something close-up, such as using mobile devices, screen time and reading a book, can increase eye strain for those who do this for long periods of time.”
Digital eye strain occurs when long periods are spent using near vision, for example, reading on screen or playing online games. Digital eye strain does not cause permanent damage to your eyes, but can be uncomfortable. The main symptom is temporary blurred vision but other signs include sore and tired eyes, dry eye and headaches.
Using screens close to or at bedtime can contribute to poorer sleep, which may mean your child’s concentration levels are lower during the day. This may be because blue light is linked to the suppression of the hormone melatonin which makes us feel sleepy. However, there are a number of other causes that may affect sleep pattern also.
Some people report that lens coatings that filter blue light make their eyes feel more comfortable or are helpful before bed, but there is no clear scientific evidence to support this. There is also no evidence that these kinds of coatings prevent eye disease.
Research into the effects of blue light is still ongoing. Some past studies revealed that exposure to blue light can lead to changes in animals’ eyes. However, because the time and intensity of exposure to blue light was more than that of natural daylight and that of screens, it does not prove blue light is harmful to human eyes.
Short-sightedness (myopia) is increasing globally. Family history, ethnic background, environment and carrying out near tasks, such as screen use, have all been linked to the development of short-sightedness. There is no clear evidence to suggest that screen time alone is the direct cause. However, there is good evidence to suggest that children who spend more time outdoors are at lower risk of developing short-sightedness.