Learn Italian: Il nonno è più cieco che miope, non ci vede affatto. - Grandpa is more blind than nearsighted, he cannot see at all.

The verb vederci is a pronominal verb that expresses the physical ability or capacity to see. If you said non vede, it would imply he isn't seeing a specific object. Saying non ci vede means his actual sense of sight is failing.

Why do we use che for "than" here (più cieco che miope) instead of di?

In Italian, when you compare two qualities (like adjectives, verbs, or adverbs) belonging to the same subject, you must use che. Because we are comparing two adjectives (cieco and miope) describing the same person (il nonno), we use che. You use di when comparing two different subjects (like "Grandpa is older than Dad").

Does affatto just mean "at all"?

Yes, but only because it is paired with non. The phrase non ... affatto means "not at all". On its own, affatto actually means "completely" or "entirely". So, non ci vede affatto literally means "he doesn't see completely," which translates smoothly to "he cannot see at all."

Why is there an "i" in cieco? Doesn't "ce" already make the "cheh" sound?