I just want to share with you how to enhance an iris quickly using Adobe Lightroom 4. The process is quite easy. With Lightroom 4 they introduced a local adjustment preset for this. Just switch to the development module, select the local adjustment brush. After this choose the iris preset and make the adjustment for the eyes. It is a quick thing with great results. No need to switch to Photoshop. It's all done directly in Lightroom. But there is more. There are presets for smoothing skin or bleaching teeth. Try them out!
Optimize iris in Lightroom 4