I've tried to research this, but none of the solutions I found worked for me. I'm really just experimenting with modeling and materials, so this isn't really suppose to be anything.
Here's the link to the .blend file:
I'm trying to create an eye using the cycles nodes. From following tutorials, my understanding is that I should have an inner sphere with the color materials, and an outer sphere with a glass shader on it to give the eye some shininess and reflectivity. Unforturnately, the glass material looks very dark. If I pull the cornea sphere out of the socket, it looks like a perfectly decent glass ball, but when it's in the socked, it's incredibly dark. I'll attach images of the rendered version and of my nodes setup.