Actually it's been proven that by looking at a persons eyes you can discern a few things about if that person is telling the truth or not.
People that are lying will tend to blink more. This one has been challenged and some people just by nature blink more than others. But on average if you're lying you blink more. I've seen it...and made the offending party pay in poker too.
When someone looks up and to the right they are accessing the creative side of their brain (aka making up a lie). When they're looking up and to the left they're accessing their memory and recalling an image of the memory. Both of these patterns have been found to be true and it's how the human brain accesses and deals with information.
To give you an example a study was done. I don't know how many people they did but lets say for simplicity sake it was 100 people. They hooked up 100 people to a lie detector and took them through a test. The lie detector got it right (that they were lying) around 80% of the time. Then they put them in front of an elite poker player and went through the same test. The poker players blew away the lie detector test and got it right (that they were lying) over 90% of the time.