By Jared Norman
We’ve all heard that watching too much TV or staring at a monitor for too long can cause eyestrain and headaches. However, there is a simple solution that can reduce the eyestrain and make TV watching a much more enjoyable experience. That solution is called bias lighting.
What Causes Eye Strain
Before we go into what bias lighting is and how it can help, it is important to understand what causes eyestrain in the first place. Eyes are able to automatically regulate how much light they take in by dilating or contracting the pupil. However, the degree of dilation is triggered by the average brightness of the entire scene they are looking at, not by the intensity of a single point of light. So if the entire scene is bright, eyes are pretty good at adjusting to reduce eye strain. But if most of the scene is dark with one small area of very bright light, eyes stay dilated, letting in more light than they can handle. This is what causes eye strain.
So if a person were to watch TV with the lights on, it would greatly reduce this kind of eyestrain. But when light shines onto the screen, it lowers the contrast and introduces a glare or haziness to the image. This lack of clarity not only dilutes the TV watching experience, it can also cause its own kind of eyestrain.
How Bias Lighting Helps
Bias lighting is when lighting is placed behind the screen being watched so that it raises the ambient light levels in the room without directly shining light toward the viewer or toward the screen. Because it raises the ambient light levels, it allows the pupils to contract, reducing the amount of light they take it. And since there is no light shining on the screen itself, there is no annoying glare or haze.
Not only will bias lighting reduce eye fatigue, but it can also improve the image seen on the TV screen. This is possible through what’s known as the simultaneous contrast illusion. The bar that stretches across the image below is one solid shade of gray, but it appears to be lighter against a dark background and darker against a light background. Bias lighting takes advantage of this same illusion to make the grays and blacks on the screen appear richer.
How to Get the Benefits
Luckily, gaining the benefits of biased lighting is easy. There are some pretty inexpensive bias lighting kits that have everything included. They consist of an easy-to-trim strip of LED lights that have an adhesive on the back, making it easy to attach to HDTVs and monitors of virtually any size. The entire thing is USB powered so it can be plugged right into the TV if desired.
That being said, it is possible to make a DIY solution using regular light bulbs. In such scenarios it is important to pick the right color temperature of light bulb. White lightbulbs range from warm light to cool light, measured in Kelvins. While any bias lighting is better than nothing, it is best to match the bias light to the reference point used by screen manufacturers. That perfect light temperature is 6500K. If you get a bias lighting kit, you don’t need to worry about it since they all should use 6500K LEDs.
Either way, it is so easy and inexpensive to set up a bias lighting solution there is no reason to continue dealing with the eyestrain, headaches, and all around discomfort that comes from watching a bright TV in a dark room, especially since bias lighting results in higher contrast images with no glare.