GreenLine® PrismView™ Blades - AMERICAN PROFILE The English PrismView and American PrismView blade may be used: • when the view of the vocal cords is impaired, especially the most anterior larynx • during nasal intubation • for post operative examination of the larynx Both contain an optically polished prism which provides a refraction of 30° without image inversion. To prevent condensation, warm the prism before use by immersing the entire blade in warm water.