Create selection of the eyeball using elliptical marquee tool. Press Ctrl+J to copy paste the selection in a new layer. Hide the layer.
Create selection of the eye area using polygon lasso tool. Press Ctrl+J to copy paste the selection in a new layer. Select stamp tool and clone the area.
Unhide the eyeball layer. Move this layer right above the "stamped eye area" layer in layer order in layer palette. Press Ctrl+Alt+G to create a clipping mask.
