Restoration of binocular single vision following multiple treatments for longstanding bilateral internuclear ophthalmoplegia and unilateral third nerve paresis in Chiari II malformation

Gemma E Arblaster,John P Burke

doi:10.22599/bioj.60

Abstract

Aim: To present a patient with longstanding bilateral internuclear ophthalmoplegia and unilateral third nerve paresis in Chiari II malformation who achieved binocular single vision with the help of prisms following two surgical and two botulinum toxin procedures. Method: The case is discussed of a 34-year-old man who presented with a longstanding exotropia and a gradually increasing abnormal head posture to achieve fixation. Investigation, treatment and follow-up to discharge are described. Results: The patient initially underwent surgery with the aim of improving cosmesis of the exotropia and the abnormal head posture, but functionally beneficial stereopsis and field of binocular single vision were achieved with multiple treatments including Fresnel prisms. Conclusion: Functional results are achievable, even in cases of longstanding strabismus associated with complex ocular motility and neurological defects.

Highlights

Internuclear ophthalmoplegia (INO) is characterised by a decreased ability to adduct one or both eyes that is caused by a lesion in the medial longitudinal fasciculus (MLF)
Bilateral cases that exhibit a large exotropia in primary position are sometimes referred to as ‘walleyed bilateral INO’ (WEBINO)
2 patients achieved stereopsis post-operatively and again the testing method used is unclear. This case highlights the fact that cosmetic as well as substantial subjective and objective functional improvements can be achieved in longstanding strabismus, even in cases of Chiari II malformation causing bilateral INO and unilateral third nerve palsy

Summary

Introduction

Internuclear ophthalmoplegia (INO) is characterised by a decreased ability to adduct one or both eyes that is caused by a lesion in the medial longitudinal fasciculus (MLF). Patients with a unilateral or bilateral INO may demonstrate binocular single vision (BSV) in primary position, often in the presence of an exophoria. Correspondence and offprint requests to: Gemma Arblaster, Orthoptic Department, A Floor Outpatients, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 5SL. Infection, hydrocephalus, brainstem and fourth ventricle tumours, and Chiari malformation. In Chiari II malformation part of the cerebellum, the lower part of the brainstem and part of the fourth ventricle herniate down through the foramen magnum into the neck area; and it is associated with spina bifida.[1] Patients with spina bifida are known to suffer from a range of ophthalmic problems, mostly related to hydrocephalus, which is caused by the coexisting Chiari malformation

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