7 Neuro-Ophthalmology
7.1 Cranial Nerve III (Oculomotor) Palsy
7.2 Cranial Nerve IV (Trochlear) Palsy
7.3 Cranial Nerve VI (Abducens) Palsy
7.4 Cranial Nerve VII (Facial) Palsy
7.5 Optic Nerve Function
7.6 Visual Fields to Confrontation
7.7 Pupils
7.8 Horner’s Syndrome
7.9 Nystagmus
7.10 Neuro-Ophthalmic Differential Diagnoses and Aetiologies
7.9 Nystagmus
This is often a poorly taught topic and is very difficult to approach. We find that the best approach to deciphering a nystagmus is through a structured clinical examination while applying pattern recognition and going through the most likely causes of Nystagmus in Adults vs Children.
1. Observation
- Look for evidence of Albinism
- Abnormal head posture (which may be at the patient’s null point seen in congenital motor nystagmus)
- Monocular or Binocular
- Look for an Esotropia (seen in Latent Nystagmus, Nystagmus blockage syndrome, cianca syndrome)
2. Visual Acuity
- For distance and near (the nystagmus may dampen on accommodation)
- Poor visual acuity may suggest a sensory pathology in the anterior / posterior segment
3. Spectacles
- Note whether the patient’s nystagmus is more pronounced with and without spectacles
4. Ocular Motility
- Assess the motility which may be limited as seen in ciancia syndrome
- Assess the characteristic of the Nystagmus (Mnemonic: DWARF)
Direction
Name in the direction of the fast phase
Plane: horizontal, vertical, torsional; uniplanar vs. multiplanar
Waveform
Jerk vs. pendular
Fine vs. coarse
Amplitude
Small, moderate, large
Rest
Dampens at null point, with convergence?
Or conversely does it increase with fixation?
Frequency
Small, moderate, large
5. Cover test
- Cover test for distance to elicit a latent nystagmus
6. Accommodation
- The nystagmus may dampen with accommodation (primary congenital nystagmus, nystagmus blockage syndrome)
7. Anterior and Posterior Segment Examination
- Anterior and Posterior segment examination looking for evidence of ocular pathology (e.g. Optic nerve hypoplasia, congenital cataract, anterior segment dysgenesis)
8. Cycloplegic Refraction
- Perform a cycloplegic refraction
- Nystagmus secondary to bilateral ocular pathology (eg Lebers Congenital Amarousis; CSNB; Aniridia, Congenital cataracts)
- Nystagmus secondary to cortical pathology (eg non-accidental injury, cortical visual impairment, brain tumours)
- Latent nystagmus (LN): Nystagmus of the non-occluded eye
- Manifest LN: Latent nystagmus with a background of suppression in one eye
- Nystagmus blockage: Variable angle esotropia and accommodation reduces the nystagmus
- Cianca syndrome: Large angle Esotropia, bilateral limited ABDuction from a tight medial rectus
- Congenital nystagmus: Improves with accommodation, presence of a null point, bilateral conjugate jerk nystagmus
- Consider all the clinical examination observations and possible differential diagnoses as seen in a child with the addition of other differentials
1. Observation
- Look for evidence of Albinism, Parkinsonism, a recent CVA (other neurological deficits)
- Look for evidence that the patient has poor vision (white cane, magnifying glass, wheelchair, guide dog)
- Abnormal head posture (which may be at the patient’s null point)
- Look for a strabismus / ptosis / anisocoria (associated cranial nerve palsies from a brainstem pathology)
2. Visual Acuity
- For distance and near (the nystagmus may dampen on accommodation)
3. Spectacles
- Note whether the patient’s nystagmus is more pronounced with and without spectacles
4. Ocular Motility
- Assess the motility which may be limited in an internuclear ophthalmoplegia (INO)
- Assess the Nystagmus (Mnemonic: DWARF)
Direction
Name in the direction of the fast phase
Plane: horizontal, vertical, torsional; uniplanar vs. multiplanar
Waveform
Jerk vs. pendular
Fine vs. coarse
In which position? i.e. primary or gaze related (INO)
Amplitude
Small, moderate, large
Rest
Dampens at null point, with convergence?
Or conversely does it increase with fixation?
Frequency
Observe for specific patterns of nystagmus
- Brun (Cerebello-pontine angle tumours)
- Towards lesion = low frequency / large amplitude
- Away from the lesion = high frequency / small amplitude
- INO: Abducting nystagmus on abduction of the eye contralateral to the lesion
- Oculopalatal tremor: Pendular nystagmus which is vertical and torsional with palatal tremor
- Peripheral vestibular nystagmus: Mixed horizontal-torsional component
- Central vestibular nystagmus: jerk nystagmus confined to one plane (purely vertical / horizontal / torsional)
- Downbeat nystagmus: Pathologies below the cranio-cervical junction (Chiari malformation, cerebellar disease, drugs such as anti convulsants, lithium toxicity
- Upbeat nystagmus: Pathologies above the cranio-cervical junction (Demyelination / Tumours / CVA affecting the brainstem, cerebellum, superior cerebellar peduncle)
- Seesaw nystagmus: Parasellar tumour (e.g. pituitary adenoma, craniopharyngioma)
- Hemi-seesaw nystagmus: Unilateral midbrain haemorrhage, medullary infarcts, syringobulbia, and Chiari malformation
- Periodic alternating nystagmus: Alternating horizontal Jerk which originates in the nodulus & uvula in the cerebellum
- Square wave jerks: Cerebellar pathology and Parkinson’s disease
- Opsoclonus: Chaotic, multidirectional saccades, without intersaccadic intervals seen with Parainfectious encephalitis, Paraneoplastic syndromes, pontine & thalamic haemorrhage
- Convergence-retraction nystagmus: seen in Parinaud’s syndrome with dorsal midbrain pathologies
- Superior oblique myokymia: Torsional oscillopsia (must rule out vascular compression of 4th nerve)
All rights reserved. No part of this publication which includes all images and diagrams may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the authors, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law.
Vitreoretinal Surgery Online
This open-source textbook provides step-by-step instructions for the full spectrum of vitreoretinal surgical procedures. An international collaboration from over 90 authors worldwide, this text is rich in high quality videos and illustrations.
