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Emergence of Diplopia and Oscillopsia due to Heimann-Bielschowsky Phenomenon after Cataract Surgery

¹Department of Neurology, College of Medicine, Seoul National University, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea
²Department of Ophthalmology, College of Medicine, Seoul National University, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea

Correspondence: Dr Ji Soo Kim
Email: jisookim{at}snu.ac.kr Department of Neurology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea. Tel: 82-31-787-7463 Fax: 82-31-719-6828.

Date of acceptance:18 Apr 2008

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Introduction

The Heimann-Bielschowsky phenomenon (HBP) refers to coarse vertical oscillation of the eye with impaired vision.1 The ocular movements are strictly monocular occurring only in the eye with amblyopia. The vertical oscillation is of equal velocity in both vertical directions or may be greater in the downward than upward direction. HBP develops several years after loss of vision. HBP can be differentiated from dissociated nystagmus in spasmus nutans, congenital nystagmus, and internuclear ophthalmoplegia based on the strict unilaterality, vertical direction, and low frequency.1 Previously, only a few reports described a development of oscillopsia due to HBP after cataract surgery, which resolved spontaneously or responded to gabapentin.2 However, visual impairments due to diplopia or oscillopsia from HBP after cataract surgery have received little attention. We report a man who developed persistent vertical diplopia and oscillopsia due to HBP after a cataract operation, which markedly impaired his vision.

Case Report

A 45-year-old man was referred for evaluation of vertical diplopia and oscillopsia which developed after a cataract surgery of his right eye. He had sustained a needle injury limited to the right globe 20 years before, which resulted in impaired vision of the right eye (perception of hand motion only). Two months before the referral, the patient underwent an anterior vitrectomy and intraocular lens insertion with a diagnosis of traumatic cataract. After the surgery, the visual acuity in the right eye improved from hand movement perception to 20/70. However, on removing the eye gauze after the surgery, the patient began to notice binocular diplopia, and visual distortion and vertical oscillopsia of the right eye. The image from the right eye appeared to be displaced forward and leftward. He reported no diurnal variation. He had a history of hypertension and diabetes. Family history was unremarkable.

Examination showed rightward head tilt which aggravated more on attempted fixation. Visual acuities were 20/70 in the right eye and 20/30 in the left eye. The visual acuity did not improve during pinhole viewing and intraocular pressure measured normal in both eyes. Extraocular movements were full in both eyes. He appeared to have small right exotropia and hypotropia, however, his inability to fixate on a target due to continuous wandering of his right eye did not permit exact documentation. The right eye showed irregular and slow pendular movements mainly in the vertical direction. The ocular oscillation aggravated when fixating on a distant object, especially in up gaze. The left eye did not show any involuntary movements (Video). The patient did not show any evidence of fusion on Worth 4 dot test at both distance and near, and he did not recognize any of the forms, animals or dots in the Randot stereo test®. Video-oculographic recording (SMI, Teltow, Germany) of the vertical oscillation revealed smaller waves with higher frequencies (0.3-4°, 0.3-1.5 cycles/second), which were superimposed on the lager amplitude and low frequency pendular oscillations (3.7-13°, 0.05-0.2 cycles/second, Fig). Without fixation, he showed subtle left beating nystagmus and minimal oscillation of the right eye. He showed an impaired convergence on attempted viewing a near target, probably due to the inability to fuse. Video-oculographic recording of the horizontal smooth pursuit also documented bilateral impairments. However, horizontal and vertical saccades were normal. Other findings of neurological examination were normal. He showed abnormal extorsion of the right eye (15.6- 24.8°, normal range: 0-12.6°), which worsened in downward gaze. Thyroid function tests, serum anti-acetylcholine antibody titer, and brain MRI were normal.

Comment

Our patient developed vertical diplopia and oscillopsia after cataract surgery along with vertical pendular oscillation of the eye with long standing visual loss due to traumatic cataract. The visual symptoms reported by the patient coincided with the ocular oscillation of the right eye, which was consistent with HBP. The mechanism of HBP remains unknown. The oscillation even in the primary position and absence of gaze-evoked nystagmus preclude dysfunction of the gaze-holding network or the common neural integrator. Monkeys with monocular visual deprivation using a patch show vertical drifts of the unseeing eye only. In view of the strict monocular nature of the oscillation in the eye with visual loss, dysfunction of the fusional vergence mechanism or monocular stabilization system seems most plausible in HBP.

Previously, oculography of HBP documented monocular vertical oscillation with the amplitude ranging from 3 to 50° and the frequency from 0.12 to 5 cycles/second. The frequencies of HBP appeared to be inversely correlated with amplitudes. The oscillation usually decreases during convergence and gaze direction exerts various effects on the intensity of oscillation. Patients may show two or more wave forms superimposed on one another. A low frequency wave with large amplitude may be superposed on smaller amplitude and higher frequency waves, as was in our patient. More careful examination may reveal even smaller amplitude of upward deflection. In a previous report on HBP, saccades, smooth pursuit, and the vestibulo-ocular reflexes were measured normal.1

Neuro-ophthalmologic complications of cataract surgery include central nervous system toxicity, binocular diplopia, traumatic optic neuropathy, and ischemic optic neuropathy. Post-operative, binocular diplopia may develop secondary to anisometropia or previously unrecognized misalignment. Periocular injection may cause paresis or fibrosis of the extraocular muscles.

HBP disappeared when the visual acuity was restored in a patient with presenile cataract and HBP.1 However, patients may develop diplopia and oscillopsia due to HBP after cataract surgery.3 Even though the pre-operative medical records did not document HBP in our patient, the typical patterns of ocular oscillation consistent with HBP, and the diplopia and oscillopsia developed after cataract surgery support an emergence of the visual symptoms due to restoration of the vision after the cataract surgery.

In HBP, the ocular oscillation may be easily missed or disregarded due to its irregularity, low frequency, and low amplitude, especially in the eye with poor vision.1 In view of the visual impairments due to diplopia and oscillopsia from HBP after cataract surgery in our patient, presence of involuntary ocular oscillation should be sought carefully in the eye with cataract before deciding surgical restoration of the vision.

References