Refraction and muscular imbalance, as simplified through the use of the ski-optometer

by Daniel Woolf

Movements of Divergence

In passing from a position of convergence to a position of parallelism, the lines of sight separate or diverge. This movement of divergence is a simultaneous, equal contraction of both externi; or, probably, of both actions combined. The eyes may even diverge somewhat beyond parallelism, as in overcoming prisms, base in, when looking at a distant object.