As her eyes neutralized Koshirou's technique, Oboro unintentionally granted Gennosuke the oppurtunity to use his genjutsu to make Koshirou create a vortex in front of his face that obliterated his eyes and rendered him permanately blind.
Oboro unintentionally granted Gennosuke the oppurtunity to use his genjutsu to make Koshirou create a vortex in front of his face. This vortex in front of his face obliterated his eyes. Oboro unintentionally rendered him permanately blind. Her eyes neutralized Koshirou's technique.