Opsoclonus

• Introduction

Opsoclonus, often associated with myoclonus and ataxia in the opsoclonus-myoclonus syndrome (OMS), presents a unique challenge in neuro-ophthalmology. Its sudden onset and dramatic presentation make it a critical sign for orthoptists to recognize and assess accurately [1].

• Clinical Characteristics

Opsoclonus is characterized by:

Involuntary, multidirectional eye movements

High frequency (10-15 Hz) and large amplitude (up to 45°)

Persistence during sleep and with eyes closed

Often accompanied by myoclonus and ataxia in OMS

• Etiology

Common causes include:

Paraneoplastic syndromes (e.g., neuroblastoma in children, small cell lung cancer in adults)

Viral infections (e.g., West Nile virus, Epstein-Barr virus)

Autoimmune disorders

Toxic-metabolic conditions

Idiopathic cases (50% in adults)

• Orthoptic Assessment

Visual Acuity and Refraction

Challenging due to constant eye movements

Use of dynamic retinoscopy techniques

Eye Movement Recording

Video-oculography for quantitative analysis

Distinction from other saccadic intrusions (e.g., square wave jerks)

Functional Vision Assessment

Evaluation of reading ability and daily visual tasks

Assessment of oscillopsia severity

Associated Ocular Motor Deficits

Screening for concurrent strabismus or nystagmus

• Differential Diagnosis

Orthoptists play a crucial role in differentiating opsoclonus from:

Ocular flutter (horizontal-only saccades)

Nystagmus (rhythmic, with slow and fast phases)

Saccadic dysmetria

• Management and Prognosis

While treatment is primarily directed at the underlying cause, orthoptists contribute to management through:

Regular monitoring of oculomotor function

Collaboration in rehabilitation strategies

Patient education on adaptive techniques

Prognosis varies depending on etiology, with paraneoplastic cases often improving with tumor treatment, while idiopathic cases may have a more prolonged course [2].

• Conclusion

Orthoptists play a vital role in the accurate assessment and ongoing management of opsoclonus. Their expertise in eye movement disorders is crucial for early detection, differential diagnosis, and monitoring treatment efficacy. As research advances, orthoptists must stay informed about new assessment techniques and potential therapeutic approaches for this challenging condition.

Note : This document serves educational purposes exclusively and does not constitute medical advice or treatment guidelines