Related Experiment Video
Updated: Aug 18, 2026

Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients
Published on: March 29, 2022
[Effects of presbyopia on clinical phoria]
1Institut für Hygiene und Arbeitsphysiologie, Eidgenössische Technische Hochschule, Zürich.
Background:
Due to accommodation-vergence cross-link we can expect that presbyopia will affect vergence as well. From investigations of cross-link as function of age one may assess strain of visual system due to presbyopia. Furthermore, this observation will give hints on innervation of ciliary muscle.
Material And Method:
Vergence is assessed as function of stimulus of accommodation in 27 subjects (24-65 years).
Results:
Presbyops tend to be exophoric for near vision. Vergence is linked to accommodation by means of a quadratic polynome rather than by a linear function.
Conclusions:
We may expect, that missing vergence strains visual system of presbyops. Results support Hess-Gullstrand theory of presbyopia and indicate a loss of innervation of ciliary muscle with increasing age.
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