This painful infection causes bleeding from the eyes and eventually blinds the victim.

A Beast or Humanoid that drinks water tainted by sight rot must succeed on a DC 15 Fortitude or become infected. One day after infection, the creature's vision st Arts to become blurry. The creature takes a -1 penalty to Attack Rolls and Skill Rolls that rely on sight. At the end of each Long Rest after the symptoms appear, the penalty worsens by 1. When it reaches -5, the victim is Blinded until its sight is restored by Magic such as lesser restoration or heal.

Sight rot can be cured using a rare flower called Eyebright, which grows in some swamps. Given an hour, a character who has proficiency with an Herbalism kit can Turn the flower into one dose of ointment. Applied to the eyes before a Long Rest, one dose of it prevents the disease from worsening after that Rest. After three doses, the ointment cures the disease entirely.