Copy from : Rafe Carson, Digital art & Photography
1. Open your eyes in photoshop (no pun intended) and duplicate their layer. Change the top layer to multiply. This will darken your composition.
2. Place a Mask Selection on your multiply layer and mask out the lighter areas. This will vary the darker areas and give your image a variety of depth in contrast.
3. Next select the Dodge tool and use it over the eyes to illuminate the outer edges. Doing so, will automatically brighten those eyes.
4. If you want to add color to those eyes. Make a new layer, select the paintbrush tool and paint the color you choose over the eyes. Once you have done so, change the layer to soft light. You may have to select a different layer opacity depending on your original image.
There you have it. A quick and easy way to make sparkling colorful eyes.