Belay glasses
Belay glasses are eyeglasses with prismatic lenses that are used by belayers in rock climbing to avoid the neck strain associated with belaying.
Description
Belaying involves a person standing on a stable platform below a rock climber controlling the tension and friction of the climber's rope. Since this activity requires craning one's neck to look up at the climber, a common malady named "belayer's neck" can occur. The prismatic lenses of the belay glasses are arranged so as to bend light from above through total [internal reflection] into the observer's eye, allowing the belayer to observe the climber while maintaining a comfortable head/neck position.The design based on the eyeglasses frame provides for a split field of vision:
- the central field through the lenses, providing a vertical view to the climber;
- the peripheral field around the sides of the lenses, allowing the belayer to remain aware of their surroundings.
Development