This is a very quick video I made to demonstrate manually removing red-eye in Photoshop. This method can be used for fixing pet eyes too, which don't reflect red and therefore are not corrected using automatic red-eye removal tools.

You can alter the size of the brush using the slider above the workspace (set to 16 in the video).

Changing the opacity is making the layer partially transparent. So our painted pupils appear less dark. If you wanted to keep the gleam in the eyes, use the eraser tool (with a small brush size) to erase this layer over where the white highlights appear.

Hope it helps!

Kathie