This is a frequently asked question, especially by those who feel that their eyes get strained if they watch television in a dark room. They are concerned if the eye strain contributes to damage to the eyes or they will need glasses if they continue this habit or even they will develop some serious eye diseases. Here are three informative articles regarding this issue.
The notion that watching TV in a dark room is bad for your eyes or, at least, causes eyestrain has been around for a long time. The problem is said to result from the contrast in light between the brightly lit TV screen and its darkened surroundings. The “harm” in this case was thought to be eyestrain, not any long-lasting damage to the eyes.
The huge difference between the brightness of TV screen and its surrounding is the key factor causing eye strain.
“Eyestrain can occur when the eyes are fixed on an object for a long period of time, there is poor lighting, or there is glare,” explains John Bullough, Ph.D., lighting scientist at the LRC and lead researcher on the television study. “One scenario believed to cause eyestrain is watching television in a dark room. In this case, visual discomfort is caused by the large difference in luminance between the television screen and the room’s dark background.”
The repeated dilatation and constriction of pupils is also responsible for eye strain.
Finally you need to understand ‘contrast ratio’. This happens when you look at white lighting or bright colors on a black or dark backdrop. When you do this your eyes won’t know quite what to focus on – the dark or the bright and this can mean that they will again be forced to keep switching between the two and repeatedly dilate. This again causes fatigue and eyestrain and can tire you out – but again remember it won’t cause any permanent damage.
Image by David Boyle