The Heimann-Bielscholwsky phenomenon: Dissociated vertical nystagmus

Background: The Heimann-Bielschowsky phenomenon (HBP) is a unilateral verti cal nystagmus with coarse, slow pendular movements that typically occurs in an eye with profound visual loss. There are no sinister neurological impli cations. Methods: Symptoms and signs on presentation and the subsequent course are d escribed in detail in 10 patients. Eye movements were recorded for one pati ent. Results: Three patients had corrected vision of 6/24 or between. Strabismus was seen in eight patients. Symptoms of diplopia and oscillopsia were infr equent. Conclusions: We believe that the HBP may be a reasonably common condition. although very under diagnosed. This condition may be similar to Central Fus ion Disruption. Patients with HBP appear to have lost the potential for fus ion.