A new surgery for congenital nystagmus: Effects of tenotomy on an achiasmatic canine and the role of extraocular proprioception

The role of vision in postural control is crucial and is strictly related to the characteristics of the visual stimulus and to the performance of the visual system. The purpose of this investigation was to evaluate the effects of chronically reduced visual cues upon postural control in patients affected by Congenital Nystagmus (CN). These patients have developed since birth a postural strategy mainly based on vestibular and somatosensorial cues. Fifteen patients affected by CN and 15 normal controls (NC) were enrolled in the study and evaluated by means of dynamic posturography. The overall postural control in CN patients was impaired as demonstrated by the equilibrium score and by the changes of the postural strategy. This impairment was even more enhanced in CN than in NC group when somatosensorial cues were experimentally reduced. An aspecific pattern of visual impairment and a pathological composite score were also present. Our data outline that in patients affected by CN an impairment of the postural balance is present especially when the postural control relies mainly on visual cues. Moreover, a decrease in accuracy of the somatosensory cues has a proportionally greater effect on balance than it has on normal subjects.

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Hereditary congenital nystagmus and gaze-holding failure: The role of the neural integrator

Neurology ◽

10.1212/wnl.43.9.1741 ◽

1993 ◽

Vol 43 (9) ◽

pp. 1741-1741 ◽

Cited By ~ 21

Author(s):

L. F. Dell'Osso ◽

B. M. Weissman ◽

R. J. Leigh ◽

L. A. Abel ◽

N. V. Sheth

Keyword(s):

Congenital Nystagmus ◽

Neural Integrator ◽

Gaze Holding

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The role of ocular oscillations upon visually dependent postural stabilization in patients affected by congenital nystagmus

Journal of Vestibular Research ◽

10.3233/ves-2000-104-504 ◽

2000 ◽

Vol 10 (4-5) ◽

pp. 201-206

Author(s):

Gustavo Savino ◽

Anna Dickmann ◽

Fabrizio Ottaviani ◽

Walter Di Nardo ◽

Luigi Scullica ◽

...

Keyword(s):

Visual Acuity ◽

Postural Control ◽

Visual Cues ◽

Normal Subjects ◽

Congenital Nystagmus ◽

The Gaze ◽

Postural Stabilization ◽

Normal Controls ◽

Better Than

Visually dependent postural stabilization decreases as a consequence of a long-standing reduction of visual cues in patients affected by congenital nystagmus. The aim of the present study was to verify whether the changes in postural control in this group of patients are due to ocular oscillations or to reduced visual acuity. Therefore, postural control was evaluated when the nystagmus was blocked by the blocking position or by prisms and compared with the postural score observed in a group of normal controls whose visual acuity had been artificially reduced to the same level as that of the patients using Bangerter's filters. The results show a statistically significant improvement of visually dependent postural stabilization when ocular oscillations are inhibited either by the gaze blocking position or by prisms. They also show that postural control in normal subjects with Bangerter's filters is reduced, but is still significantly better than that observed when ocular oscillations are inhibited in patients affected by congenital nystagmus. Our data strongly support the role of ocular oscillations in visually dependent postural control, since postural impairment recovered under any condition in which ocular oscillations were abolished, despite differences in visual acuity. Our data also show that reduced visual acuity decreases visually dependent postural control to a lesser degree than ocular oscillations. This could be due to the fact that ocular oscillations are a disturbing input, usually inhibited centrally, in order to avoid oscillopsia. This mechanism is probably responsible for the reduced role of visual cues in the postural control in this group of patients. The reduction of visual acuity, by comparison, merely causes a decrease in visual cues, depending on the degree of visual loss. It can be concluded that the impaired postural control in patients affected by congenital nystagmus is mainly due to ocular oscillations, with reduced visual acuity creating a secondary effect.

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Role of contact lenses in the management of congenital nystagmus.

British Journal of Ophthalmology ◽

10.1136/bjo.67.12.834 ◽

1983 ◽

Vol 67 (12) ◽

pp. 834-836 ◽

Cited By ~ 33

Author(s):

E. D. Allen ◽

P. D. Davies

Keyword(s):

Contact Lenses ◽

Congenital Nystagmus

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A small gene sequencing panel realises a high diagnostic rate in patients with congenital nystagmus following basic phenotyping

Scientific Reports ◽

10.1038/s41598-019-49368-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Luke O’Gorman ◽

Chelsea S. Norman ◽

Luke Michaels ◽

Tutte Newall ◽

Andrew H. Crosby ◽

...

Keyword(s):

Diagnostic Yield ◽

Congenital Nystagmus ◽

High Diagnostic Yield ◽

Infantile Nystagmus ◽

Targeted Ngs ◽

Causal Variants ◽

Next Generation Sequencing Ngs ◽

Changing Role ◽

Generation Sequencing

Abstract Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of ‘real-world’ diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.

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