According to "Shoyuki" (Diary of FUJIWARA no Sanesuke), the reason for the eye disease of Emperor Sanjo was the wraith of Gasho who could not become the head of the Tendai Sect after serving under FUJIWARA no Motokata as the naigubu (a special monk who held a position in the imperial court).
藤原実資の『小右記』によれば、三条天皇の眼病の原因は藤原元方と内供奉を務め後に天台座主になれずに憤死した賀静の怨霊であることが記載されている。