Dawnguard’s nocturnal female eyes.
Sunguard, vampire male eyes.
There are four different degrees of vampirism. The longer a vampire goes without feeding, the more severe the infection becomes. Humans who fall asleep during the night can be fed on to stave off the curse. After witnessing a feeding, onlookers often turn violent and notify the Hold Guards. A bounty of 40 Gold is placed in the corresponding Hold upon successful feeding. The crime has no price, not even in Gold or prison time. Once a vampire reaches stage four, detection by humans becomes easier, and they are more likely to take immediate action (either attacking or running away) when they see one.
With the Dawnguard expansion, you gain access to a Vampire Lord ability with eleven perks as you level up. By joining forces with Lord Harkon and the Volkihar Clan, the Dragonborn initiates the Elder Scrolls-predicted Tyranny of the Sun. A player can earn a trophy for unlocking all 11 bonuses. Also, when the Dragonborn reaches stage four of vampirism, characters no longer become hostile; this only occurs when the Dragonborn is in Vampire Lord form.