Adjusting the challenge level for permanent disadvantages in 5E

My players should be heading for a mount to find a blind giant, defeat him, and get a passkey to a dead wizard's blah blah blah.

My party is five players of seventh level and will most likely be eighth by the time they find him. The giant was blinded years ago. What CR or differing giant would you use to make a challenge for a party of 8th level of the baddie is blind? I don't want to give the giant blindsense. The giant is in a rage because he was smited blind years ago.

Party: Circle of Moon Druid, Bard, Sorcerer, Artificer, Warlock

Thanks for any thoughts.