Literally all other eye movements are together, or conjugate.
Accommodation and vergence are normally tightly coupled physiological processes. As an example, when focusing your eyes on something in the distance and then shifting your attention to an object closer to you, that process starts with your eyes converging on that object in the near field. This results in the image of that object appearing larger on the retina and out of focus. That blurriness in turn triggers the accommodation reflex, which results in a change in the focal power of the crystalline lens bringing the image on the retina into sharp focus.
The vergence and accommodation processes are extremely important for virtual and augmented reality enthusiasts to understand. As pointed out in Chapter 21, users of flat panel-based stereoscopic head-mounted displays often complain of headaches and eye strain. That side effect is caused by the eyes having to remain focused on a flat plane (the display surface) that is within inches of the eye. Even if you are paying attention to and accommodating for objects at what appear to be differing focal planes within the virtual space, the depth of field is just simulated. The imagery presented to each eye is portrayed on a 2D display surface, and that is where the eye remains focused. Ultimately, this constant focusing in the near field on the surface of the display elements, which is made possible by the constricting of the ciliary muscle surrounding the edge of the lens, greatly contributes to such discomfort. Further, there is a mismatch, or decoupling, in the sensory cues provided to the brain by the vergence and accommodation processes.
An additional aspect to the vergence cue just described comes in the form of tension in the six extraocular muscles shown in Figure 3.