I have the following screen shot. My problem, is there is a grey area inside the lense. I know it should have some grey for the alpha blending, but not this.
Should I just use alpha clipping, and make the lense alpha zero?
And your grey spot has (really) a different material with transparency?
I unplugged the alpha from the diffuse map.
I checked the eye, and I could not find any duplicate vertices, or any faces for the grey area.
I’ll try and recreate the material.
The material shares one texture. So there is one material for the whole eye.
I askes because you aren’t showing your setup, it was some kind of rhetorical question and i assumed that there is some texture sharing between the material. So you checked double (trouble 
) vertices in geo an UV… okay. But then:
How should the lense be transparent when… uh ohh controlling transparency of the eye lense with alpha in image is avery bad idea… too different materials.
