laser eye surgery questions to ask

i am having a science test in a few days about eyes, how we see light and how we see colour?

it is about eyes, how we see light, how we see colour, parts of the eye that sees the light and gives the message to the brain, (so far i know the lense and the retina but dont know what they do, and something to do with reflection refraction, about concave and convex, and i know a question will ask ” what can laser surgery do to the eye to make you see better. i need to know of anyone has done anything like this or if there is anything i should know, we are aloud to bring in a sheat of paper and i need allo of these thing on, and key words. PLEASE HELP. it is a very important test and i am in year 8 (but to you americans i do not know grades so i will say i am 12-13 years old

OHH! I love this subject!
Okay, to start you off, white light is made up of all the colors, right? So, white light is absorbed by EVERYTHING that it hits. If the object reflects all of the colors back to you, then you will see white. If the object absorbs all the colors in the white light but only reflects blue, then you will see those objects as blue. If the object absorbs all the white light and only reflects green, you will see the objects as green. For example, trees absorb all the colors except for green, so your eyes pick up the green light.
Now, your eye is made up like this:

http://www.macula.org/anatomy/

(click on the blue circle “the eye”)
first, the light passes through the front of the eye, a clear bubble (like a contact lens) called the cornea. Then, the light passes through the lens, which is right behind the cornea. The cornea and the lens bend the light so it will hit the back of your eye (the retina) at an exact point:
This is a great video:

(skip to 45 seconds into the video)

At this point, the object is “seen” by your retina as upside down. Then, the retina sends the light signal to your brain. The brain flips the image and your brain “sees” the image as right side up. So, in the end of the day, your eyes don’t see, but your brain does.
Laser surgery just shaves your cornea to shape it correctly so that light can be bent so it will be focused directly on the retina.
Good luck!