I wanted to know if it's possible to apply a radial filter just to faces; I started by noticing that there's a section in which lightroom organize all the faces, so maybe there's a way to apply a special filter to those: it would be really useful, also to eyes specifically.
Thank you a lot,
have the best day ever.
There's no setting to apply radial filters to just faces.
However, you could draw a radial filter to cover a face (and likely other nearby parts of the photo) and then use the erase brush to remove the effect of the radial filter over parts of the photo that you don't want the radial filter to affect.
The keyboard shortcut to create a copy of the Radial filter can be useful for group shots of people.
Create one Radial Filter circle that covers one face, then hold [Ctrl+Alt] keys as you click and drag on the black spot pin and you have another identical Radial filter for another face. Repeat as required.