Vertical deviation coupled to convergence

Purpose: To report on a 7-year-old boy with a small left-over-right deviati on (-VD) which increased when the head was tilted to the left shoulder and during convergence. Methods: The squint angles were measured by the unilateral and alternate pr ism cover test at distance and near fixation when the head was in orthoposi tion and when it was tilted. Results: At distance fixation (D) there was a latent deviation of -VD 3 deg rees. With near fixation (N) at 0.3 m the vertical phoria in-creased to -VD 18 degrees. The angle of deviation was not influenced by (N) convex lenses in front of the fixating eye despite an adequate desaccommodation. The - V D was fairly comitant in right and left gaze. At 45 degrees head tilt to th e right shoulder the - VD decreased to (D) 2 degrees and (N) 12 degrees. At 45 degrees head tilt to the left shoulder the -VD increased to (D) 18 degr ees and (N) 26 degrees. A dissociated vertical deviation was excluded by th e dark red glass test and by the reversed fixation test. Conclusion: The disturbance can be explained by a, presumably congenital, s upranuclear misinnervation and has to be differentiated from other types of vertical deviation.