[Analysis of vergence movements using differential photo-oculography]

Analysis of vergence troubles is weight by an heavy handicap. In clinical conditions it is easy to value the static vergence balance with a great lot of tests. On the contrary examination of kinetic vergence pattern is generally neglected. Usually a refixation vergence is a combination of an horizontal convergence-divergence of 5 to 10 degrees with a vertical component of 15 to 20 degrees. It is impossible to do their reliable analysis by kinetic EOG because the unequal transmission of potential towards the orbital rim. The authors give the results obtained by photo-oculographic method perfected by Charlier and Buquet. On all recordings it can be noticed that, in vergence refixation, vertical movements of both eyes are always true congruent saccadic versions, while the horizontal movements are disjunctive, dissociated and unequal. On the vertical axis it seems to be no real kinetic vergence at all, but in some cases only a mere tonic alignment. Such a device is a very good mean to study the vergence troubles in daily practice.