it is necessarty to fill this gap ? on eyeball? I am making a lowpoly character , and like to animate in couples of days, but I would like to know if I need to fill this limit ? this rings of the edge loops around the eye? consider this is the first loops of the eye or the final, depends how you can see it, I ve started to model over this area with few verts on it, however I am on the eye right now, see the picture, must leave it away? or fill the interior ? 



see the whole picture.
If you're working low poly it would better to close it and colour it black. It would be different if you were going for max realism but at the moment I don't think it's necersarry. You may also find it easier yo UV unrap.