Step 1: Creating a Back up Layer
Open the file and create a duplicate layer : Layer-> New-> Layer Via Copy. Having a second duplicate will be helpful as your back up in case you overdo the process.
Step 2: Enhancing the iris:
Choose the Dodge tool , and from the options bar at the top of your screen, lower the Exposure to about 30%. Size the brush cursor so that it fits only the iris area (be careful not to brush over the dark outer edge of the iris).
Step 4: Enhancing the Iris border
Here, pick your Burn tool and increase your exposure to 50%. SIze your brush so it covers only the iris border. Start applying the brush little by little. Make sure not to darken a lot as it will start looking more like an horror movie pic!
and that's it!! this should really take no more than 5 minutes and you will have gorgeous light eyes!
Sorry I couldn't post more pics for this tutorial. I am in the process of learning how to blog.
Enjoy.
Milenka.