infravergence
Also called negative vertical vergence, deorsumvergence, vertical fusional vergence (base-up), infra-vergence
Infravergence is the vertical fusional vergence in which one eye rotates downward relative to the other to keep an image single.1,4 Supravergence is the upward counterpart, and together the two form the vertical fusional reserve.1,4
Vertical vergences exist only as small compensating adjustments of muscle tone: a slight vertical misalignment, from a hyperphoria or a prism, drives one eye to shift until the two images fuse.4 Infravergence should not be confused with infraversion, in which both eyes move down together.
Infravergence is measured by adding base-up prism before one eye until double vision appears (the break) and reducing the prism until the image is single again (the recovery).1,2,5 The normal range is small, about 2 to 3 prism diopters.1,2,5
More detail
Infravergence of the right eye is the movement that compensates a right hyperdeviation.1 Older texts call the pair deorsumvergence and sursumvergence.4 The test has no blur finding, because accommodation does not change during a vertical vergence.2 A large vertical reserve points to a long-standing deviation such as a congenital fourth nerve palsy, and a small reserve points to a recent deviation.3
Sources (5)
- Scheiman and Wick, Clinical Management of Binocular Vision, ch. 2
- Carlson and Kurtz, Clinical Procedures for Ocular Examination, ch. 4
- Eperjesi and Rundström, Practical Binocular Vision Assessment, ch. 6
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 4
- Kanski, Clinical Ophthalmology (2024), ch. 18
Reviewed October 2026