Management of Nystagmus – the Ophthalmologist’s perspective Dr. R.R.Battu Consultant Pediatric Ophthalmologist Narayana Nethralaya Bangalore

Historically What is the presenting feature? Informant::: Nystagmus - “Wobbly eyes” Anomalous Head Posture Poor vision Photophobia Night blindness Oscillopsia Vertigo Diplopia Head nodding Many times a combination of the above !!

Historically Family history Poor vision Nystagmus Neurological disease

Historically When did this start? At birth or shortly thereafter [ “Congenital” or infantile nystagmus ] Congenital sensory or motor nystagmus Congenital neurological nystagmus Rare variants PAN Spasmus nutans

Historically Medication Occupation [ - and hobbies? ] Epilepsy Anticonvulsants Sedatives “Psychiatric medications” Occupation [ - and hobbies? ] Epilepsy Head Trauma Neurological abnormalities…….. Craniofacial anomalies

Is there a visual defect? Is this likely to be an “ Ocular nystagmus” If so, qualify and quantify Is this likely to be an “ Ocular nystagmus” Sensory defect nystagmus [ SDN ] Latent nystagmus [ LN/ MLN ]

Observe One time observation Multiple session observation Usually required in children Tired adults

What to Observe The eye The alignment The nystagmus Anomalous Head position

The Eye Evaluate refractive error Evaluate the anterior segment Evaluate the posterior segment

Visual Acuity Behaviour Eye poking Pre verbal child or infant Fix and follow Other techniques

Special problems with Latent nystagmus - Infantile Esotropia Fogging Polarised glasses – Vectograph Neutral density filter Remote occlusion The Spielman Occluder

The Eye Microphthalmos Obvious malformations AFFERENT PUPILLARY DEFECT

The Eye Iris The lens Obvious or subtle transillumination defects Ocular or oculocutaneous albinism is usually a straightforward diagnosis. The anterior segment clues you onto the typical posterior segment abnormalities The lens Cataract

The Eye Optic nerve abnormalities Retinal abnormalities Hypoplasia Atrophy Coloboma Retinal abnormalities Albinism Macular hypoplasia Cicatricial ROP Dysplasia Pigmentary retinopathy

Nystagmus Compensation Syndrome The Alignment Ortho, Eso or Exo? In an infant: Eso - Infantile esotropia with LN/MLN Nystagmus Compensation Syndrome Exo – Infantile exo, many times with neuro-developmental issues

The Nystagmus Pendular or Jerk Direction Frequency and Amplitude Variation with gaze Variation with convergence Variation with monocular occlusion Binocular symmetric Binocular asymmetric Monocular

“How long” to “observe” ? Single concentrated ‘effort’ of observation of at least 3 minutes !!! Periodic Alternating Nystagmus

Serious neurological disease? Asymmetric nystagmus Monocular nystagmus Visual pathway disorders ! Vertical nystagmus Purely torsional nystagmus

Evaluation Asymmetric nystagmus INO Spasmus nutans Rarely Congenital nystagmus Parasellar tumours Restrictive or paralytic ocular muscular disorders

Congenital Idiopathic Nystagmus Observation Most commonly horizontal Pendular or jerk Horizontal nystagmus in vertical gaze positions [ Uniplanar ] Null position – Eccentric or on near gaze Usually symmetric Fulcrum of rotation in “apparently” asymmetric nystagmus.

Congenital Idiopathic Nystagmus Typically 3 phases of development [ Dr. Robert Reinecke] Phase 1- Broad triangular wave form [ 3-6 mths] Phase 2- low amp pendular waveform [6-24 months] Phase 3-Typical jerk nystagmus [24-36 months] Historically: No oscillopsia Invariably improves with age

Spasmus nutans Head nodding Anomalous head position Monocular/asymmetric nystagmus – “ Shimmering” RULE OUT CNS TUMOUR [ glioma ]

Latent nystagmus/ Manifest Latent Nystagmus Probably the only cause of Infantile nystagmus which does not need Electrophysiologic study or Neuro imaging

Latent nystagmus Beats away from the covered eye [ towards the fixing eye ]

Anomalous Head Position Null point Beware PAN Wandering Null point Usually in an eccentric gaze position Head is positioned AWAY from the null point i.e. Null point to left, face turn to right Mostly lateral turn, occasionally vertical and cyclovertical head turns

Electrophysiology ERG, EOG and VER Would probably be indicated in most situations as an initial ‘workup’ May allow to avoid neuroimaging

Neuro imaging Again, would probably be required as an initial workup, unless there is unequivocally ophthalmic cause of nystagmus evident on examination and Electrophysiology

TREATMENT Drug treatment Optical treatment Chemodenervation Surgical treatment

Drug Therapy - Specific Pendular Nystagmus – Gabapentin and Memantine PAN – Baclofen Superior Oblique Myokymia – Carbemazipine, Gabapentin

Drug Therapy – Less specific Pendular – Valproate, Trihexyphenidyl, Isoniazid, Cannabis Downbeat nystagmus – 3,4 diaminopyridine, 4 aminopyridine, gabapentin, clonazepam, baclofen Any form of Nystagmus – Clonazepam, baclofen

CORRECT REFRACTIVE ERROR Optical treatment CORRECT REFRACTIVE ERROR

Refraction in nystagmus Binocular UCVA in forced pp Binocular UCVA in preferred AHP

Refraction in nystagmus Binocular retinoscopy with patient fixing either in AHP or forced PP Put the lenses in front of both eyes, fog one eye by 1-3 lines Subjectively refract other eye Repeat on the other side If there is no strabismus ( orthophoric), then add upto 7pd BO prism and -1.0DS to the prescription, observe nystagmus and check binocular acuity Repeat all steps with cycloplegia

Factors which can be improved Visual acuity VA, contrast sensitivity, colour, motion sensitivity, gaze angle Anomalous Head Position Congenital nystagmus, acquired nystagmus, convergence damping, adduction null in LN/MLN Oscillopsia Acquired nystagmus, decompensated congenital nystagmus Hypo accommodation Photophobia

Refractive Correction In children upto 10 years, full cycloplegic refraction In adults, subjective, try to push over time if there is a difference in sub and obj refraction

Amblyopia therapy May significantly decrease or eliminate MLN …… LN Periods of occlusion have to be very prolonged in patients with LN Alternatively fogging or penalisation may have to be used

Optical treatment To direct the null point centrally Prisms placed with apex directed towards the null point. Large power prisms may have to be used. Fresnels May degrade vision

Optical treatment To stabilize visual image on the retina High plus spectacle with high minus contact lens[ -58 & +32 ] Entire 30 deg field focussed to centre of eye, and CL refocuses to the retina. Image remains stable irrespective of eye movement !!

Optical treatment To induce convergence Base out prisms bilaterally Induce a convergence Useful only if there is a convergence null May have to compensate with a -1.0 sph for induced accommodation

Chemodenervation Botox 2.5 – 5 units into all horizontal recti Retrobulbar injection of 25 – 30 units

Chemodenervation Useful to reduce amplitude of nystagmus Has been shown to improve foveation time and improve visual acuity slightly. More useful in neurological acquired nystagmus, particularly in oculopalatal myoclonus RB injection effect lasts for several weeks

Chemodenervation Complications include Ptosis Diplopia Filamentary keratitis

Electronystagmography Nystagmovideography

Surgical principles Decrease the amplitude of nystagmus Maximal recession of horizontal muscles Tenotomy Increase foveation time Broaden the null zone

Induce an attempt to converge Rotate the null zone Anderson Goto Kestenbaum Parks’ modification of Kestenbaum Augmented Kestenbaum 40% 60% Induce an attempt to converge Artificial divergence surgery

Face turns - horizontal Surgery to correct AHP Face turns - horizontal Anderson advocated bilateral recession Eg. Null zone to left, weaken levo- ‘verters’ Kestenbaum advocated recess-recess [ pull and push] Park’s modification of Kestenbaum’s 5-6-7-8 rule [both eyes get 13 mm ] Very rarely corrects more than 10 -15 degrees

Surgery to correct AHP Augmented K-A procedure Problems Classic + 40% - For > 30 deg of face turn Classic +60% - for > 45 deg of face turn Problems Intractable diplopia

Surgery to correct AHP Vertical AHP Chin up Chin down IR recess – SR resect Chin down IR resect– SR recess Anteriorisation of IO

Patient with right horizontal gaze palsy and head turn of approximately 20° to the right (a); the same patient 1 year after recession of right medial rectus and left lateral rectus muscles (b). Note: the patient can use his glasses more effectively. Patient with acquired nystagmus equilibrium in upward gaze; CHP with chin-down is present (c); the same patient 1 year after surgical weakening of both superior rectus muscles (d). E C Campos1, C Schiavi1 and C Bellusci1. Surgical management of anomalous head posture because of horizontal gaze palsy or acquired vertical nystagmus Eye (2003) 17, 587–592. doi:10.1038/sj.eye.6700431

Surgery to correct AHP Cyclovertical AHP As an adaptation to torsional nystagmus Surgery to recreate the torsional direction ‘created’ by the patient’s head tilt Several methods Strengthen or weaken obliques Slanting recti insertions Vertical recti slanting

Surgery Other problems Management of co existent strabismus with nystagmus Acquiring of a new head position - PAN Creating a new strabismus

Surgery primarily designed to improve vision Artificial divergence Bimedial recession Unilateral recess-resect to XT 4 – muscle retro equatorial recession 10 mm MR and 12 mm LR Ideal for PAN May induce an exotropia

Dell’Osso & Hertle Based on the principle of enthesial proprioceptive input to nystagmus at the insertion of the horizontal recti Dell'Osso LF. Extraocular muscle tenotomy, dissection, and suture: A hypothetical therapy for congenital nystagmus. J Pediatr Ophthalmol Strab 1998; 35:232-3. Hertle RW, Dell'Osso LF, FitzGibbon EJ, Thompson D, Yang D, Mellow SD. Horizontal rectus tenotomy in patients with congenital nystagmus. Results in 10 adults. Ophthalmology 2003; 110:2097-105. Hertle RW, Dell'Osso LF, FitzGibbon EJ, Thompson D, Yang D, Mellow SD. Horizontal rectus muscle tenotomy in patients with infantile nystagmus syndrome: a pilot study. JAAPOS 2004; 8:539-48.

Summary Evaluation of nystagmus is multidisciplinary However, it is possible to improve the quality of life with drugs/optical devices/surgical procedures No single procedure has shown to be consistently predictive of success This does not mean we cannot try.

Thank you