Glass is used to provide light and allow vision through otherwise opaque surfaces.

It is the part of the brain that allows vision.

This allows vision to develop normally in that eye.

There were no windows, but enough light managed to enter through the thin walls to allow adequate vision.

As a conscious sense organ, the mammalian eye allows vision.

This will keep deer from feeding near roads and allow better vision for drivers.

The eyes are not focused, but simply allow vision to come in from the entire field, so that you look at nothing but see everything.

The eyes are effectively working together to allow good vision at near, intermediate and far, without needing glasses.

This will stop your eyes wandering about the page but still allows peripheral vision so that you are able to anticipate what is coming next.

Part or all of the face, with spaces to allow vision, could also be covered.