What is vergence (convergence & divergence)?
Vergence is the process of muscular coordination which points each eye at the same point in space to produce binocular vision. To see at the near point, the eyes must cross or “converge”, while to see at the far point, the eyes must pull out or “diverge”. Vergence works strongly in coordination with accommodation and pupil dilation. Vergence is principally governed by the medial recti and the pupilary contractions by the sphincter pupillae. The strong synkenetic association between these three is seen by the supply of all these muscles by one nerve called the third cranial. It is common to find in most vision problems that the three systems are not acting in coherence.
