Fusional vergence is the movement of both

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

s that enables the fusion of

monocular A monocular is a compact refracting telescope used to magnify images of distant objects, typically using an optical prism to ensure an erect image, instead of using relay lenses like most telescopic sights. The volume and weight of a monocul ...

images producing

binocular vision In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an ...

. It is especially important when a person has

heterophoria Heterophoria is an eye condition in which the directions that the eyes are pointing at rest position, when ''not'' performing binocular fusion, are not the same as each other, or, "not straight". This condition can be esophoria, where the eyes ten ...

. Premotor cells for fusional vergence are located in the mesencephalon near the oculomotor nucleus.

References

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