Orthophoria is a condition of
binocular fixation in which the lines of vision meet at the object toward which they are directed, and considered as a normal condition of balance of
the ocular muscles of the two eyes.
The condition opposite of Orthophoria, is called
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 ...
.
References
Ophthalmology
Vision
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