Sunbeam's text reads:
A beam of brilliant light flashes out from your hand in a 5-foot-wide, 60-foot-long line. Each creature in the line must make a Constitution saving throw. On a failed save, a creature takes 6d8 radiant damage and is blinded until your next turn. On a successful save, it takes half as much damage and isn't blinded by this spell. [...]
You can create a new line of radiance as your action on any turn until the spell ends.
Is my understanding of how this spell works correct?
My interpretation: A creature may be affected by beams over and over. If a creature makes its saving throw, it can no longer be blinded by additional beams. However, on subsequent turns, it still needs to make a Con save against the damage. Is that correct?