The People Who Own the Dark (1976)

An elite group gathers in an ancient castle to enjoy a few days of partying and lust while a nuclear war is being waged outside. Protected in their privileged refuge, they have become immune to the effects of radiation. However, when they go out in search of supplies, they discover that the people outside the castle have been blinded. Now, they face the fury of those affected, who are willing to do anything to bring justice and wipe them out.