Was reading your posts here and sup with Itachi casting Genjutsu with his finger?
I believe it was with his ring and before Sasuke attacked Itachi on the throne the Itachi that was stabbed before on the ground he showed him the ring really nicely while pointing on the throne.
Nope. Itachi is capable of casting genjutsu with his fingers. He points that out to Naruto (No pun intended). His ring is just a ring.