The Heimann-Bielschowsky Phenomenon (HBP) is a slow, coarse, pendular, amplitude-varying monocular vertical nystagmus seen in eyes with severe visual impairment. It is considered a type of dissociated nystagmus.
First reported in 1902 by German ophthalmologist Ernst Heimann, it was described in patients with strabismic amblyopia, multiple sclerosis, neurosyphilis, and epilepsy. Later, in 1931, Alfred Bielschowsky distinguished this similar monocular vertical nystagmus from dissociated vertical deviation (DVD), establishing the basis of the current disease concept.
There are no detailed data on prevalence, and it is reported as a rare phenomenon. Clinically, newly onset HBP may be mistaken for efferent pathway disease (posterior fossa/brainstem lesions), requiring caution.
Nystagmus in HBP is strictly monocular and observed as coarse, slow pendular vertical oscillations.
A common condition for HBP is occurrence in eyes with severe visual impairment (often 20/200 or worse).
Congenital Causes
Anterior segment dysgenesis: Congenital abnormalities of the cornea, iris, lens, etc.
Optic nerve hypoplasia: Severe visual impairment due to underdevelopment of the optic nerve.
Infantile cataract: Causes early visual deprivation.
Microphthalmia: Underdevelopment of the entire eyeball.
Sclerocornea: Visual impairment due to scleral-like changes in the cornea.
Acquired Causes
Amblyopia: Caused by visual deprivation or strabismus during the visual development period.
Absolute glaucoma: Loss of vision due to end-stage glaucoma.
Optic neuropathy: Such as optic neuritis or ischemic optic neuropathy.
Traumatic cataract: Lens opacification due to trauma.
Coexistence with dissociated vertical deviation (DVD) due to unequal visual input has also been rarely reported.
Both congenital (e.g., anterior segment dysgenesis, optic nerve hypoplasia, infantile cataract) and acquired (e.g., amblyopia, absolute glaucoma, optic neuropathy) conditions can be causes. The common factor is severe visual impairment, and it often occurs in eyes with visual acuity of 20/200 or worse.
Diagnosis is made by observing slow pendular vertical oscillations in the low-vision eye. Observation of the affected eye for 1 minute is recommended. Since nystagmus disappears during active eye movements, observation at rest is important.
Fundus examination is performed on each eye separately, followed by examination with both eyes open. When both eyes are open, latent nystagmus may be superimposed, so caution is required.
The main differential diagnoses and their characteristics are shown below.
| Disease name | Main features | Difference from HBP |
|---|---|---|
| Spasmus nutans | Childhood onset, head nodding, torticollis, high-frequency horizontal nystagmus | Vision is usually normal |
| Acquired pendular nystagmus (APN) | Most common in MS, elliptical/circular, 1–8 Hz1) | Binocular, with brainstem/cerebellar signs |
| Ocular neuromyotonia | Intermittent tonic spasms, lasting seconds to minutes | Normal vision adults, spontaneous or after eccentric gaze |
| Oculopalatal myoclonus | After brainstem infarction, 1–3 Hz, persists during sleep | Torsional + vertical components, binocular |
| See-saw nystagmus | One eye elevates and intorts, the other depresses and extorts, 2–5 Hz | Binocular due to chiasmal tumor, etc. |
Currently, no effective pharmacotherapy has been shown to improve nystagmus in HBP.
Gabapentin and memantine are effective for acquired pendular nystagmus (APN), a differential diagnosis of HBP, but their applicability to HBP is unknown.
The results of surgical therapy are inconsistent.
No effective drug therapy has been demonstrated to date. Regarding surgical therapy (such as Faden surgery and superior rectus recession), some studies report a reduction in oscillations, but results are inconsistent and no standardized treatment protocol has been established.
The exact mechanism of onset of HBP is unknown. It is classified as a type of dissociated nystagmus.
Leigh et al. have proposed the following two mechanisms.
Pathophysiological differences from DVD: DVD is characterized by better best-corrected visual acuity and slow downward deviation without nystagmoid movements, suggesting a different mechanism from HBP.
Comparison with acquired pendular nystagmus (APN): APN is caused by visual system disorders or lesions in the Guillain-Mollaret triangle (dentato-rubro-olivary pathway). It differs from HBP in having a wider frequency range of 1–8 Hz 1) and being binocular.
No new interventional studies on HBP itself have been reported at this time. However, knowledge on pharmacotherapy for acquired pendular nystagmus (APN), a related nystagmus condition, is accumulating and may contribute to understanding the pathophysiology of HBP in the future.
Kerkeni et al. (2022) reported a case of APN in a 49-year-old woman with progressive multiple sclerosis treated with memantine 20 mg/day combined with a blinking strategy1). Memantine alone improved visual acuity from 0.063 to 0.12 (equivalent to 2 lines), and further improvement to 0.16 was achieved with the addition of blinking. It was also confirmed that nystagmus suppression lasting approximately 400 ms was obtained after blinking.
However, this is a report on APN, and its applicability to HBP is unclear. The efficacy of pharmacotherapy including memantine for HBP has not been demonstrated, and further research is awaited.
