Possibilities of prismatic correction in the treatment of congenital horizontal nystagmus

Purpose. Analysis the effectiveness of prismatic correction in the treatment of congenital horizontal nystagmus. Material and methods. The study included 20 patients with congenital horizontal nystagmus. Depending on the type of nystagmus and compensatory mechanisms to reduce its amplitude, two groups were identified: 10 patients with pendular nystagmus and nystagmus blockage syndrome (mean age, M±sd, 5.8±1.9 years) and 10 patients with jerky nystagmus and abnormal head posture and a null zone (5.7±2.1 years). Fresnel prisms were used to select and prescribe prismatic correction. Patients were under dynamic control from 6 months to 2 years with an assessment of the results every 3 months. Results. During treatment (using prism correction), uncorrected visual acuity had a statistically significant increase of 1.8 and 1.5 times both in the first (p=0.004) and the second (p=0.001) group, respectively. A similar, and even more pronounced, change in visual acuity was observed for corrected visual acuity – in the first group it increased 3 times (p=0.001) and in the second group 2.2 times (p=0.001). Conclusion. Prismatic correction in pendular nystagmus and esotropia allows to simulate (eliminate) nystagmus blockage syndrome and, thereby, to improve the quality of vision of the patient. In its turn, prismatic correction in jerky nystagmus with abnormal head posture allows to move null zone into the primary position of gaze, increase visual acuity due to the optimal optical correction and improve the patient's quality of life. Key words: nystagmus blockage syndrome, convergence fusion, abnormal head posture, null zone, Fresnel prisms

Pendular Nystagmus

Pendular nystagmus often occurs in the setting of multiple sclerosis, but it can also occur in the syndrome of oculopalatal tremor. It has a sinusoidal waveform such that there are slow phases in both directions without corrective quick phases. Because it can cause disabling oscillopsia, many affected patients request treatment. In this chapter, we begin by reviewing the clinical features and pathogenesis of pendular nystagmus occurring in the setting of multiple sclerosis. We next review the clinical features and pathogenesis of oculopalatal tremor, which is most commonly a delayed consequence of brainstem tegmentum or cerebellar stroke. Lastly, we review the medical treatment options for pendular nystagmus, which include gabapentin and memantine.

The Heimann-Bielschowsky Phenomenon: A Retrospective Case Series and Literature Review

Background The Heimann-Bielschowsky phenomenon (HBP) is an unusual form of monocular vertical pendular nystagmus and is usually asymptomatic. It always occurs in an eye with longstanding, profound visual loss. Reports of HBP are few and HBP is probably underdiagnosed. Recognition of HBP could prevent unnecessary and potentially harmful investigations. The purpose of this study was to report a series of patients with HBP and to summarise the international literature on the subject in order to better define the clinical presentation of HBP. Patients and Methods The study was approved by the local ethics committee. Medical records of patients diagnosed with HBP and examined by one of us (F. X. B.) were retrieved. Eye movements were quantified, either from video or eye tracking recordings, in all patients. The international literature on HBP was reviewed using the keywords “Heimann-Bielschowsky” or “monocular nystagmus”. Results From 2007 to 2017, we retrieved seven patients with HBP. In the literature, we found only 8 publications, accounting for 66 cases. In both our cases and those from the literature, VA was worse in the eye with HBP and was usually ≤ 20/200. Visual loss was either congenital or acquired and resulted from a variety of aetiologies. The eye movement was strictly monocular, pendular, mostly vertical, but sometimes oblique. Characteristically, its frequency was irregular but low (0.2 to 2.6 Hz in our cases, 0.05 to 5 Hz in the literature) and its amplitude very variable (1 to 9° and 1.5 to 50°, respectively). Extraocular movements were always preserved. Conclusions HBP is a benign monocular eye movement disorder that is always secondary to severe visual loss. Being asymptomatic, HBP is still under-recognised and easily overlooked. Furthermore, both amplitude and frequency of HBP may be small and irregular. Recognition of HBP is mandatory in order to prevent costly, unnecessary, and potentially hazardous investigations, and caution is advised, as cataract surgery might be responsible for postoperative oscillopsia.