Ok... where it has the "Alpha_blend" for the eye glow, is that supposed to glow bright? If so you might try changing it to "Scene_blend add"
Or if the images are .png (guessing they are?) i noticed if they're compressed at all the transparency takes on the taint of the color, but you'd think that both eyelids would do it..
i had a similar visibility problem with eyes once. In daylight they'd change which side was visible depending on where the light was hitting it. Underground they'd remain the same side visible, other not. Try testing it in different environments and see that happens?
