Management of Nystagmus – the Ophthalmologist’s perspective

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

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

3. Historically • Family history • Poor vision • Nystagmus • Neurological disease

4. 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

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

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

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

8. What to Observe • The eye • The alignment • The nystagmus • Anomalous Head position

9. The Eye • Evaluate refractive error • Evaluate the anterior segment • Evaluate the posterior segment

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

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

12. The Eye • Microphthalmos • Obvious malformations • AFFERENT PUPILLARY DEFECT

13. The Eye • Iris • 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

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

15. 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

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

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

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

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

20. 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.

21. 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

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

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

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

25. 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

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

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

28. TREATMENT • Drug treatment • Optical treatment • Chemodenervation • Surgical treatment

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

30. 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

31. Optical treatment CORRECT REFRACTIVE ERROR

32. Refraction in nystagmus • Binocular UCVA in forced pp • Binocular UCVA in preferred AHP

33. 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

34. 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

35. 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

36. 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

37. 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

38. 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 !!

39. 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

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

41. 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

42. Chemodenervation • Complications include • Ptosis • Diplopia • Filamentary keratitis

43. Electronystagmography Nystagmovideography

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

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

46. 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

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

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

49. 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

50. 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