supravergence
Also called positive vertical vergence, sursumvergence, vertical fusional vergence (base-down), supra-vergence
The vertical fusional vergence in which one eye rotates upward relative to the other to keep an image single; infravergence is the downward counterpart, and together they form the vertical fusional reserve1,2. 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 fuse3.
Supravergence should not be confused with supraversion, in which both eyes move upward together. It is measured by adding base-down prism before one eye, which makes that eye rotate upward, until the patient reports double vision, and the normal range is small, about 2 to 3 prism diopters2,4.
More detail
After the break the prism is reduced until the image is single again, the recovery. There is no blur finding, because accommodation does not change2. The horizontal reserves are far larger, about 15 to 20 prism diopters for convergence and 6 to 10 for divergence at distance4. Supravergence of the right eye compensates a right hypodeviation1, and the control of vertical vergences in the brain is not well understood3.
Sources (4)
- Scheiman and Wick, Clinical Management of Binocular Vision, ch. 2
- Carlson and Kurtz, Clinical Procedures for Ocular Examination, ch. 4
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 4 and ch. 12
- Kanski, Clinical Ophthalmology (2024), ch. 18
Reviewed October 2026