The screencap you provided is similar to the cornea in VSS.  All you will need to do is create a new rule under Shader Rules, and name it lenscovering.  Connect it to the Copy Template Cornea, then resave your VSS prop.  If you are applying this particular VSS shader to multiple characters, I would not worry about changing any name convention you have already established.  VSS will skip and ignore shader Lenscovering in any character that does not have that particular material zone.