For those who want to try to understand the eye in scientific terms, here is a link:http://clarkvision.com/imagedetail/eye-resolution.html

What it basically says to me is the eye and brain need to do a lot of work to process a large complex image, especially one that occupies a large percentage of the field of view. Field of view is the amount of image defined as a vertical angle and a horizontal angle. 90 degrees is a rough number excluding peripheral vision areas. Think of it as looking through a cone that has a 90 degree angle between the opposite sides.

It would be like looking at a wall hat is 10 feet by 10 feet from 5 feet away. If the whole wall is active visual stimuli, that is a 100 percent being visually processed. If there is a 5 x 5 foot screen, then 25% needs to be processed if the brain can disregard the the images on the wall. But, if our visual filtering is not functioning well, the brain will still try to process the images on the wall.

This is why it is sometimes easier to watch a screen in a darkened room.

This same problem is a big part of ADD/ADHD struggles in the classroom. Teachers often have too much visual stimuli on the walls, especially at the front of the room. This over-stimulates the ADD/ADHD student. If the disruptive student has been seated at the rear of the classroom, his struggles become much worse.

I know, too much information. I'll turn off the fire hose.