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Squint Club 2006. ACTIVE TREATMENT OF CONGENITAL NYSTAGMUS: RATIONALE & RESULTS LIONEL KOWAL LOTS of assistance from Drs Elaine Wong, Steven Bush, Joanne.

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Presentation on theme: "Squint Club 2006. ACTIVE TREATMENT OF CONGENITAL NYSTAGMUS: RATIONALE & RESULTS LIONEL KOWAL LOTS of assistance from Drs Elaine Wong, Steven Bush, Joanne."— Presentation transcript:

1 Squint Club 2006

2 ACTIVE TREATMENT OF CONGENITAL NYSTAGMUS: RATIONALE & RESULTS LIONEL KOWAL LOTS of assistance from Drs Elaine Wong, Steven Bush, Joanne Dondey & Larry Abel SQUINT CLUB 2006 LIONEL KOWAL LOTS of assistance from Drs Elaine Wong, Steven Bush, Joanne Dondey & Larry Abel SQUINT CLUB 2006

3 Squint Club 2006 OVERVIEW OF THIS TALK  1. Overview of cong N  2. Treatments  3. Audit of recordings  4. Audit of surgeries  1. Overview of cong N  2. Treatments  3. Audit of recordings  4. Audit of surgeries

4 Squint Club 2006 APOGOLIES FOR DIFFICLUT TERNIMOLOGY Congenital Aperiodic Periodic Alternating Nystagmus  PAN Latent Manifest Latent Nystagmus  LMLN, aka Fusion Maldevelopment Syndrome or FMS Dual Jerk nystagmus : Not a personal insult - combination pendular plus jerk nystagmus Nystagmus usu referred to as N

5 IN OFFICE ASSESSMENT OF CONGENITAL NYSTAGMUS Types of congenital nystagmus - how to differentiate them in the office

6 2 Main types of congenital N: Lower case ‘ cN ’ = congenital N = any sort of very early onset N 1.Congenital N Upper case ‘ CN ’ - a specific type of cN Synonyms : Congenital Motor N Idiopathic Infantile N IIN

7 2 Main types of congenital N: 2. LMLN Latent Manifest Latent N Synonyms: Manifest Latent N Fusion Maldevelopment N FMNS

8 Squint Club 2006 Congenital N Result of abnormal bilateral symmetric acuity development @ a CRITICAL PERIOD in very early visual devpt. Hence frequent association with : OCA [foveal ± disc dys- / hypo- plasia], high refractive errors, bilateral optic n hypoplasia, PVL, bilateral cong cataracts, …..

9 Squint Club 2006 LMLN Result of Asymmetric acuity development and/or abnormal development of binocularity @ a CRITICAL PERIOD in very early visual devpt hence associated with CET, early monocular visual loss, PVL, …

10 Squint Club 2006 CN Involuntary, bilateral, conjugate [RE = LE] oscillation beginning ≤ 6 mo Usually horizontal ± torsional Decreased at certain angle[s] = null zone NZ Blocked with convergence [also NZ]

11 Squint Club 2006 CN Commonly gaze evoked: –R beating in R gaze actually to R of NZ –L beating in L gaze actually to L of NZ Usual CN waveform [decreasing velocity slow phase] is UNIQUE

12 Squint Club 2006 Acuity in CN : FOVEATION When eye changes direction, speed of oscillation slows down in order to reverse direction = foveation period [velocity < 5 º /sec; flat part of the EMR]

13 Squint Club 2006 Acuity in CN : FOVEATION BCVA depends on: 1.Duration of foveation period 2.Persistence and effect of factors that initiated the CN [foveal hypoplasia, optic n hypoplasia, high cyls, … ]

14 Squint Club 2006 CN: 2 NZs LITTLE / NO N ECCENTRIC NZ : drives AHP Usu stable / ‘hard wired’ but can vary time / age Can be turn, tip, tilt [T 3 ] or combo. Same with either eye fixing CONVERGENCE NZ near acuity better than distance medial recti ‘brake’ the CN

15 Squint Club 2006 CN Natural history: 3 phases over the first 12mo Phase I : first 2-3 mo of life –Purposeless eye mvmts - as if blind –No jerk N –large amp, low frequency ‘triangular’ –No voluntary horizontal pursuit / saccades –Normal vertical OKN, pursuit and saccades - excludes apparent blindness & avoids MRI

16 Squint Club 2006 Natural history : Phase II pendular Age 6-12 mo Symmetrical, low-amplitude, pendular N May remain phase II without proceeding to phase III

17 Squint Club 2006 Natural history: Phase III adult waveform – Age 12+ mo –‘Adult’ jerk waveform –development of eccentric null zone with AHP –± compensatory head nodding –Phases are per Reinecke –Hertle does not show same evolution –Difference: ?sampling ?selection bias

18 Squint Club 2006 CN variant : P A N Relatively common VERY under diagnosed Melbourne: ?30% of albinos FAT SCAN IMPORTANT - are there ANY photos that shows a face turn the other way?

19 Squint Club 2006 CN variant : P A N Oscillates between 2 NZs approx 90° apart O/wise identical to CN NZ changes : cycle of 1 to 10 min Acquired PAN : cycle usu 2 min Usu Aperiodic e.g. 8 min to L & 1 min to R

20 Squint Club 2006 Latent Manifest Latent NystagmusLMLN Main EMR feature: Decreasing velocity slow phase [not unique - also gaze paretic N]

21 Squint Club 2006 Latent Manifest Latent N LMLN Main clinical feature: Fast phase to fixing eye - UNIQUE LMLN : is a conjugate bilateral monocularly ‘ driven ’ N - waveform depends on which eye is fixing, and whether that eye is in the AD- or AB- ducted position Slit lamp: T component common

22 Squint Club 2006 LMLN can resemble CN Null in adduction for each eye [less N, vision better] - can look like CN conv null Nystagmus on lateral gaze: LE in LG: BE have N  L RE in RG: BE have N  R SUPERFICIALLY SIMILAR TO GAZE EVOKED N OF CN

23 Squint Club 2006 LMLN Face turn to fixing eye 2 NZs improve VA:H & T hence 2 types of AHP NZs in LMLN are monocular NZ for blocking the H component of LMLN: fixation in adduction Medial rectus acts as a ‘ brake ’ –Face turn to fixing eye - can superficially resemble PAN

24 Squint Club 2006 LMLN Head tilt to fixing eye NZ for blocking T component of LMLN : in intorsion sup oblique acts as a ‘ brake ’ Head tilt to fixing eye Same mechanism causes DVD of other eye

25 Squint Club 2006 CN / PAN & LMLN RECAP ….

26 Squint Club 2006 Congenital N Result of abnormal bilateral symmetric acuity development

27 Squint Club 2006 WHY LMLN? Result of Asymmetric acuity development &/or abnormal development of binocularity BOTH LMLN & CN seen together in very early onset Cong ET

28 Squint Club 2006 Both CN & LMLN may have: N greater in lateral gaze Latent component N worse with monocular cf binocular fixation different mechanisms in CN / LMLN Strabismus CN: some. LN: nearly all

29 Squint Club 2006 Both CN/PAN & LMLN may have: Conv null different mechanisms Alternating face turns different mechanisms

30 Squint Club 2006 CN vs. LMLN IN OFFICE GUIDELINES T: prob LMLN OCA :  bilateral VA  CN N  fixing eye: LMLN

31 Squint Club 2006 CN vs. LMLN IN OFFICE GUIDELINES 2 Pref for fixation in ABduction : CN Smooth pursuit asymmetry: LMLN

32 Squint Club 2006 P A N Prolonged in- office exam - check AHP while talking to parents for PAN [show age appropriate DVD] FAT scan to determine consistency

33 Squint Club 2006 SLIT LAMP EXAM Look for TIDs of iris with decentred beam in a darkened room Makes OCA likely Hermansky Pudlak looks just like OCA : ask re: any possible bleeding diathesis

34 Squint Club 2006 SLIT LAMP EXAM The ‘Designs for Vision’ examination paddle with reduced Snellen chart is a good way to –determine conv null –any T component [usu LMLN] –fast phase to fixing eye –Smooth pursuit asymmetry [usu accompanies LMLN]

35 When to record and why record eye movements for nystagmus diagnosis?

36 Squint Club 2006 Does everyone with wiggly eyes need to be recorded? Usually - not if you’re absolutely certain about the diagnosis and have all the information you need for management EMR is to cN today what ECG was to arrhythmia 50 y ago - would you dream of managing an arrhythmia without ECG?

37 Squint Club 2006 What if you’re not sure? CN waveforms are unique - can confirm diagnosis Can save patient expensive imaging studies (esp. small children)

38 Squint Club 2006 What if you’re not sure? What distinctions can you make? –Acquired vs. cong types N –CN vs. cong PAN –CN vs. LMLN –N vs. saccadic oscillations

39 Squint Club 2006 CN waveforms Pathognomonic for CN Approx 15 waveforms described ‘Jerk’ or ‘pendular’ on basis of slow component Jerk waveforms may appear pendular clinically Analysis of waveform may  prognostic information about potential VA

40 Squint Club 2006 Latent nystagmus EMR often required to determine whether LN is due to CN or LMLN “The eye is quicker than the eye”

41 Squint Club 2006 Assessing effects of treating CN CN’s variability makes clinical assessment of change difficult Recording can objectively document –Changes in foveation Can facilitate better VA –Shift in null position Will reduce or eliminate AHP –Broadening of null having best possible vision over a wider range of gaze angles improves patients’ functional field of vision …all best demonstrated with EMR

42 Squint Club 2006 Summary EMR can provide clinicians with two major forms of assistance: 1) establishing / confirming a diagnosis when the clinical presentation is atypical or ambiguous 2) Document outcome of treatment

43 Modern Treatment Options In congenital Nystagmus

44 Squint Club 2006 Treatment goals in CN 1 Directly Improve VA Treat refractive error Treat amblyopia Stabilize/ reduce intensity N (increase “foveation”) to improve VA Prisms CLs Surgery

45 Squint Club 2006 Treatment goals in CN 2 Normalize head posture Prisms Surgery Broaden NZ to expand effective visual field Prisms CLs Surgery

46 Squint Club 2006 Medical treatments Drugs - barely explored New epilepsy drugs Lyrica, Memantine, Neurontin

47 Squint Club 2006 Prisms - for convergence null –Induce fusional convergence –7 ∆ base out prisms with -1 DS OU to compensate for convergence induced accommodation [CA/C ratio ] –Can be used long term –Useful preop test for suitability for artificial divergence surgery

48 Squint Club 2006 Contact lenses –  VA ≥ optical effect alone –CL sometimes expands NZ & improves foveation time –? Stimulates conjunctival proprioceptors Dell’Osso 1988. Contact lenses and congenital nystagmus. Clin. Vision. Sci. 3:229-232


50 Squint Club 2006 #1: ARTIFICIAL DIVERGENCE SURGERY Cuppers,1970’s. Popularised by Spielman 1990’s. >100 cases to AAPOS 10y ago If there is a conv null for distance with ∆, BMR creates an exophoria that ‘drives’ a conv null INDICATIONS –CN / PAN –Convergence null for distance –Some sensory and motor fusion or BMR  constant XT


52 Squint Club 2006 #2: HORIZONTAL NULL POSITION SURGERY KESTENBAUM / ANDERSON 50y history! Rc/Rs OU for face turn  13mm OU for 15º - 25º face turn Anderson* : only the Rc component 1. INDICATIONS CN with consistent Eccentric NZ R/O APAN INADEQUATE CONVERGENCE DAMPING >12 mo old (Child is walking) * Hugh Taylor’s grandfather

53 Squint Club 2006 COMPLICATIONS AND EXPECTATIONS OF KESTENBAUM / ANDERSON SURGERY Improves AHP Improves VA in many Expands NZ & effective field of vision Small Under- > Over-Corrections frequent Consecutive Strabismus infrequent but difficult Limitation of Gaze - pseudo Gaze Palsy - may never fully recover

54 Squint Club 2006 Non- specific +ve effect of CN surgery K’baum operation usu: –Expanded null zone * –Improved acuity ** IRRESPECTIVE of whether the K’Baum achieved the desired goal *Dell'Osso,L,Flynn, J.T.: Congenital Nystagmus Surgery: A Quantitative Evaluation of the Effects.Arch. Ophthalmol.97:462- 469, 1979 ** John Norton Taylor, RVEEH in Aust NZ J Ophthal, and many others

55 Squint Club 2006 Intriguing Question Does K ’ baum surgery have a non-specific +ve effect that we can exploit ?

56 Squint Club 2006 HERTLE RESEARCH 1. In beagles with cong SSN tenotomy & resuture improves the features of the EMR that correlate with improved VA 2.Proprioceptors in ‘Enthesis’ [where tendon inserts into sclera] are abnormal in human CN pts [?cause ?effect]


58 Squint Club 2006 #3: HERTLE TENOTOMY OPERATION If K’baum and artificial divergence surgery not appropriate “Tenotomy & resuture back to insertion” improves foveation on EMR in nearly all CN pts and improves VA in about 50% Hertle RW. Horizontal Rectus Tenotomy in Patients with Congenital Nystagmus. Ophthalmology. 2003;110:2097-2105

59 Squint Club 2006 #3: TENOTOMY ONLY INDICATIONS CN No alternative surgery appropriate No Convergence or Eccentric Null ≥12 mo old ≤10% of CN Patients appropriate

60 Squint Club 2006 #3A: Large Rc all horizontal recti Bietti / Bagolini 50y history Recess all muscles +++ : to suppress the CN  improve vision, cosmesis, face turns Largely abandoned in Europe - resurrected in USA / Mexico in 80’s Reinecke improves VA only in PAN

61 Squint Club 2006 4. Surgery for LMLN Reinecke Corrrect ET or XT perfectly and convert LMLN to LN Improved face turns Improved VA

62 Audit of EMR: How EMR can help diagnosis and treatment of patients with nystagmus

63 Squint Club 2006 Audit methods Files of 79 LK private patients with presumed cN reviewed 55 patients had EMR Recordings and clinical diagnosis were compared

64 Squint Club 2006 The population studied

65 Squint Club 2006 EMR versus clinical assessment n=55

66 Squint Club 2006 EMR diagnosis, Indeterminate clinical diagnosis – 33% PG, 18 presented requesting treatment of N. Vision was R 6/24 L6/30, bin 6/10. ET, Direction of fast phase unclear, convergence null Oscillopsia Uncertain office diagnosis EMR : CN

67 Squint Club 2006 Office diagnosis incorrect -16% CS, age 5, presents with a L FT and tilt. Had undergone surgery previous year for XT. R6/18 L 6/15. Fast beat in direction of fixation, no convergence null, no eccentric null. Office diagnosis LMLN EMR demonstrates CN

68 Squint Club 2006 EMR indeterminate – 11% 4 patients with APAN, all correctly diagnosed as having a CN waveform. Unable to demonstrate EMR features of APAN 1 patient with very asymmetric pendular nystagmus – CN confidently excluded but no definite diagnosis made

69 Squint Club 2006 Limitations of EMR Not readily available Equipment limitations limit assessment of vertical nystagmus and positions of extreme gaze Cooperation of patients - v. difficult under 12 mo, difficult under 2y Melbourne: LUCKY to have Larry Abel

70 Squint Club 2006 Limitations of EMR THANK YOU LARRY!

71 Squint Club 2006 Accuracy of clinical signs Clinical signs evaluated: –Direction of N ? in direction of gaze or ? to fixing eye –Convergence null –Eccentric null Final diagnosis after serial clinical assessment, FAT, EMR, and clinical conferences

72 Squint Club 2006 Accuracy of clinical signs

73 Squint Club 2006 Conclusions 1 3 tests with >95% specificity –Eccentric null in CN –Conv. null and jerk to gaze direction in CN –Jerk to fixing eye in LMLN Diagnosis made with these signs is likely to be accurate

74 Squint Club 2006 Conclusions 2 Although a good “stand alone” test, jerk to fixing eye will still miss ~25% of LMLN Convergence null and jerk to gaze direction will miss most CN

75 Squint Club 2006 Conclusions 3 EMR valuable in evaluation of cN, and will become more important if / as surgery becomes more popular Serial clinical assessment helpful esp. F.A.T in APAN – EMR may miss this diagnosis Be aware of limitations of office exam


77 Squint Club 2006 AUDIT OF LK SURGERIES seen during 2003-5 n=20 16 : EMR confirmation 10 ‘pure’ CN 3 PAN 5 LMLN [EMR 4] 2 CN + LMLN [EMR 1]

78 Squint Club 2006 KESTENBAUM n=6 2 with ≥ 1 line improvement –#1: 6/12 OU to 6/6, 6/9 –#2: 6/18 OU to 6/12 OU 5/6: AHP fixed 3/6 need 2nd surgery: 1. AHP over corrected 2. Consec XT 3. Pre-existing strab not fixed

79 Squint Club 2006 Strabismus + Hertle n=6 5 for ET & 1 for XT + Hertle on other horizontal recti 1/6 improved VA –From 6/15 OU to 6/9 OU 1/6 VA worse –From 6/30, 6/60 to 6/45, HM Comorbidities: midline brain anomalies

80 Squint Club 2006 Strabismus + Hertle n=6 1/6: fixation switch : problems 1/6 PAN. E + conv null for D confirmed with ∆ glasses. S x : NO effect on FT. 2 nd surgery to augment BMR - some improvement

81 Squint Club 2006 Artificial divergence + Hertle n=2 #1: PAN with alternating FT –Corrected #2: PAN and albinism –VA 6/36 OU to 6/22 OU –Consec XT* : 2 nd op to advance one MR –Alt FTs much improved * +ve Kappa of OCA makes this look worse

82 Squint Club 2006 Large 4 muscle Rc n=1 PAN with no face turns - null zone in primary position –Surgery MRRc 9 OU, LRRc 10 OU –VA improved 6/30 to 6/19 OU

83 Squint Club 2006 Surgery for LMLN n=2 #1: 35∆ XT with oscillopsia –MRsOU previous LR Rc OU –No oscillopsia –  VA: from R6/22, L6/25, BE 6/9 to R6/12, L 6/9, BE 6/9 #2: 45 ∆ ET –BMMRc –Residual 35 ∆ ET –No VA improvement

84 Squint Club 2006 Summary : Effect on VA –5/20 improved VA ≥ 1 line 2/5:.. to 6/12 2/5: 2 line improvement 6/30 to 6/19 6/12 to 6/6 –1/20 : VA worse no explanation

85 Squint Club 2006 Summary : Effect on AHP Any sensible surgery usu effective for AHP in CN and PAN 9/12 : improved AHP 5 require 2 nd op 3 were for residual / induced strabismus 2 required 2 nd op to improve residual AHP

86 Squint Club 2006 Summary Effect on oscillopsia Excellent 2/2 with resolution of symptoms

87 Squint Club 2006 Becoming an expert Read the following authors: 1. Hertle 2. Reinecke 3. Spielman 4. Abadi

88 Squint Club 2006 A LOT OF WORK!! FOR LITTLE BENEFIT? Ask the patients! When a snail gets a ride on the back of a tortoise, the observer isn’t impressed. The snail thinks it’s fantastic!* * Tychsen


90 FOR MORE EFFECTIVE CONFERENCE LECTURES From New Scientist, 26 January 2006, page 17 Stuart Brody [Paisley, UK] compared effects of different sexual activities on BP when a person is later stressed. 24 F & 22 M kept diaries of when they had penile- vaginal intercourse (PVI) & non- coital sex. They then underwent a stress test involving public speaking and mental arithmetic out loud. The PVI group were least stressed; their BP normalised faster than the non-coital group. Abstainers had the highest BP response to stress. The effects are not attributable to short-term relief from orgasm, but endure for at least a week. Release of oxytocin might account for the effect.

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