Step 1

The image below is a random eye image found doing search, I recommend you try using one your own photos. Open the eye image in Photoshop CS/CS2 or version 7. The technique can be used on all version of Photoshop.




Step 2

Create a new layer by clicking Layer -> New -> Layer
Or
Shift+Ctrl+N
Give the layer a name, preferably something meaningful e.g. Eye Color. This is the workspace that we will be working in to change the color of the eye.


Step 3

Select the Magnetic Lasso Tool. Now with a bit of care trace around the eye edges until the desired effect.



Step 4

Now change the colour to what ever you like, I have chosen Green
Select the Paint Bucket Tool
Click inside your Lasso to fill in the Colour.
You should have something that resemble the picture below.




Step 5

Double Click the Eye Colour Layer to display the Layer Style Properties
This can also be achieved be Clicking Layer -> Layer Style -> Blending Options
Change the Blend mode to Hue
Change the Opacity to 55%




Step 6

You can now go back and follow the same steps to apply similar effects to other parts of the eye. Below is and example of the eyelid being changed colour.