When you take pictures using a flash, your subjects can sometimes be afflicted with red eye, an annoying condition in which the iris (the colored part of the eye) glows an eerie red. You can use the Redeye tool to change the eyes to a more natural color, salvaging an otherwise unusable shot.
Open the picture for editing, click the Basic Fixes tab, and click the Redeye button. The Redeye Repair panel appears.
When you're satisfied with the results, click Apply.
Note: When viewing the edited photo, increase the magnification so you can closely examine the eyes. If they still contain red, repeat the Redeye Repair.