Button with an eye icon in the Material Preview panel

Hi to all,

I use Blender v 2.32, and in the “Preview” panel of the Shading function
(F5 in the buttons window) is present a button with an icon representing an eye (the last below). I dont’ know what is the function of this button. I click on it, but I obtain no effect.

many thank’s for your help
best regards

It refreshes the preview. In case it’s lagging.


Thank you for your help Martin.