Help please:) Changing Eye Colour

I would like to know if there is a way to change a persons eye colour without just using a paint brush, because it obviously doesnt look right or natural, if anyone can help me or even knows what im talking about it would be appreciated

First you should manage to select the eye (just the part you want to give another color, not the white). If your lucky, you can just do it with the "Eliptical Marquee tool" (top left). You better select both eyes imidiatly; use shift when you select the second eye so the first eye doesn't get deselected. If you managed to select both eyes properly, you can use the hue/saturation tool (image-->adjustments or CTRL+U). Just play with the 3 sliders till you get a satisfying result. Hue defines what color it is; the higher the saturation the better you see the colour; lightness is obvious I think. If the colour-change isn't big enough, you should tick "colorize". Another function, which is rather similar, but I think not so usefull in this case is "color balance" (CTRL+B); you can pick you color better, but the effect is different... You can try out both functions, to see which go best and to train photoshop :D .

Quick summary:
-) Select eyes
-) CTRL-U or CTRL-B

thanks a bunch, that helped alot