During this period of time, macular degeneration in both eyes caused the otherwise robust Knotts to become virtually blind. His live appearances on television were few. In 2005, Knotts parodied his Ralph Furley character while playing a Paul Young variation in a "Desperate Housewives" sketch on "The 3rd Annual TV Land Awards". He parodied that part one final time in "Stone Cold Crazy", an episode of the sitcom "That '70s Show". In the show, Knotts played Fez and Jackie's new landlord. This was his last live-action television appearance. His final role was in "Air Buddies" (2006) (a direct-to-video sequel to "Air Bud"), voicing the sheriff's deputy dog, Sniffer.