you wanna reduce cornea surface reflection of large diffuse sources?  will cause classic poser 4 "dead doll eyes" look (mostly specular), unless segregate light panels from other posersurfaces by clamp or limit diffuse.  will consider it over weekend (quitting time ~3 min. frm now), but I daresay BB already solved this.  would start with typical refl/spec math as shown below, then moderate with diffuse node. e.g. would only accept diffuse below certain limit, in case light panels had ambient > 1.0.