.In Tools, select Magnetic Lasso Tool
With Magnetic Lasso Tool selected Click on the edge of your eye ball to select, if the picture is small then enlarge it so that you can have a clear view of the eye
Below is my final result after selection
Now go to Images - Adjustments - Hue/ Saturation
Hue/Saturation Window will pop up, then play with HUE, SATURATION nad LIGHTNESS until you get desired colour
When you are done, save your picture in PNG fomart, below is my final result
