Project information
Heterophoria influence on distance and near fusion vergences (HIFUV)

Project Identification
Project Period
1/2023 - 12/2023
Investor / Pogramme / Project type
Masaryk University
MU Faculty or unit
Faculty of Medicine
Heterophoria, fusion vergence, AC/A, Von Graefe method, Howell card, prism.

Assessment of the extent of fusion vergence is one of the most important diagnostic tools for providing information on the ability to preserve binocular vision. The tendency of the eyes to deviate from bifoveal fixation is controlled by fusional vergence. Motor fusion is the basis for orthophoric eye positioning in combination with sensory fusion and stereopsis. When heterophoria is present, the misalignment of the eyes exceeds the possibilities of fusional vergence. By testing the amplitude of fusional vergence, we can establish the threshold at which problems with binocular vision appear.


In the case of both groups with exophoria (far, near)we found a statistically significant result only for negative fusion vergence (NFV). There was a statistically significant increase in NFV in sample with far and near exophoria (D EX, p = 0.01 and B EX, p = 0.02, respectively). In our study, we also demonstrated a statistically significant difference (p <0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method.

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Sustainable Development Goal No.  3 – Good health and well-being Sustainable Development Goal No.  4 – Quality education Sustainable Development Goal No.  8 – Decent work and economic growth


Total number of publications: 10

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