I have heard a lot of people saying the quote; "You eyes can deceive you, don't trust them." (Myself included) However I feel that there is a need to explain this a little bit better.
One day I walked into a music store looking for some classical music. And when I say "classical" I don't mean out of the 60's, I'm talking about Beethoven, Mozart, Bach and all the other great composers of that era. Shortly after I entered a young salesman tried to sell me a new stereo system. At this point I must add that I was wearing a tie dye shirt and a pair of fairly old jeans and had my haircut at about shoulder length. I was personally interested in buying a new stereo so I listened to his little speech. He rattled off about how this was the best stereo system to listen to heavy metal rock so you could really feel the base drumming though you bones like it would really feel like you where at a live concert. After he stopped talking I asked, "How does it work with Beethoven?" He looked puzzled at me like he had no clue who Beethoven was, which I am pretty sure he didn't. I explained to him politely who Beethoven was and he still had no clue what I was talking about so I simply did a general tour around the store, found the classical section (which I might add was extremely lacking in both quality and quantity), found the CD I was looking for and paid for it. On my way out I passed the young salesman and showed him the CD and explained who Beethoven was again and suggested that he at least check out something from Beethoven's wide works from the local library and listen too it. (Which I would encourage anyone who has never really heard Beethoven before to do.)
This is a prime example of how your eyes can deceive you at first. The second I walked in the door he stereotyped me as your typical teenager that listens to hard rock (which personally hurts my ears.) because of the way that I dress. And while I may look like your average teenager (what can I say, I wear what is comfortable, not exactly what fashion dictates and if that happens to be tie dye shirts and jeans then so be it) there is a lot more to me than meets the eye. In fact I wouldn't have to hazard too much of a guess to say that there is more than meets the eye with most if not all of the people who are reading this right now.
Another way to look at it is to see how easily the eyes can be fooled into thinking that something that is not really there is there. Look at any optical illusion for example. Also look at how much one misses during a day, when you sneeze, bend over to pick up a shiny coin or miss that special someone as they slip behind a pillar or into a store at the mall as you round the corner. Which is something that leads to the nature of invisibility but that is another thing all together.
The other thing that is mentioned is that we as human are overly dependent on our sense of site over the other four and in the case of smell it has almost diminished down to nothing. One can gather a fair amount of information from the other senses: the footsteps silently shuffling down the hallway, the slight breeze when you know someone has past, or the faint scent of perfume that you know only one person wears. Lastly when one is in tune with the Force you can sense things not through any of the five senses, like that strange tingly feeling when you know something is about to happen but you just don't know what. The information gathered from the Force is usually a lot more accurate than any of the five senses, aJedi must learn to trust the Force and the information and insights that the Force gives you.