Transmutation [Light]
Level: Sorcerer 4, Wizard 4
Components: S
Casting Time: 1 swift action
Range: Personal
Target: Your breath weapon
Duration: 1 round
You expel your breath weapon, which crackles with eye-splitting intensity.
For this spell to function, you must have a breath weapon that uses fire or electricity, either as a supernatural ability or as the result of casting a spell such as dragon breath. When you successfully cast this spell, your breath weapon is suffused with bright light. In addition to taking the normal fire or electricity damage, creatures that fail their saving throws against the breath weapon are permanently blinded. Sightless creatures are not affected by blinding breath.
Source: Spell Compendium, page 31. Previously published in Draconomicon, page 77.