Why is my visibility eye greyed out?

[Bijan Burnard]

Hi there, i have recently re installed photoshop to edit a few graphics, but whenever i try to turn on or off the visibility eye, it will sometimes grey out and sometimes will allow me to click it. Does anyone know why this is happening? 

[c.pfaffenbichler]

Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Options Bar, …) visible? 

[melissapiccone]

Are you layers in a group? If you turn off the eyeball to a group, the layers in the group will be grayed out. 

[Kevin Stohlmeyer]

If its a single layer image with Background, you can't turn that on or off.

Otherwise unless you have a dialog box open, the layer visibility (eye icon) shouldn't be restricted even if in a group/folder, etc.