Active Treatment of Congenital Nystagmus: Rationale & Results
Squint Club 2006 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 OVERVIEW OF THIS TALK 1. Overview of cong N
2. Treatments 3. Audit of recordings 4. Audit of surgeries 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 Squint Club 2006 IN OFFICE ASSESSMENT OF CONGENITAL
NYSTAGMUS Types of congenital nystagmus - how to differentiate them in the office 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 2 Main types of congenital N: 2. LMLN Latent Manifest Latent N Synonyms: Manifest Latent N Fusion Maldevelopment N FMNS Congenital N
of abnormal bilateral symmetric acuity development @ a CRITICAL PERIOD in very early visual devpt. Hence frequent association with : OCA [foveal disc dys- / hypoplasia], high refractive errors, bilateral optic n hypoplasia, PVL, bilateral cong cataracts, .. Result Squint Club 2006 LMLN 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, Result 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] 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 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 /sec; flat part of the EMR] 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, ]
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 [T3] or combo.
Same with either eye fixing CONVERGENCE NZ near acuity better than distance medial recti brake the CN 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 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 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 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? 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 Squint Club 2006
Latent Manifest Latent Nystagmus LMLN Main EMR feature: Decreasing velocity slow phase [not unique - also gaze paretic N] 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 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 Squint Club 2006 LMLN Face turn to fixing eye 2
NZs improve VA:H & Thence 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 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 Squint Club 2006 CN / PAN & LMLN RECAP Squint Club 2006 .
Congenital N of abnormal bilateral symmetric acuity development Result Squint Club 2006 WHY LMLN? of Asymmetric acuity development &/or abnormal
development of binocularity Result BOTH LMLN & CN seen together in very early onset Cong ET 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 Squint Club 2006 Both CN/PAN & LMLN may have: Conv null
different mechanisms Alternating face turns different mechanisms Squint Club 2006 CN vs. LMLN IN OFFICE GUIDELINES T:
prob LMLN OCA : bilateral VA CN N fixing eye: LMLN Squint Club 2006 CN vs. LMLN IN OFFICE GUIDELINES 2 Pref for fixation in ABduction : CN
Smooth pursuit asymmetry: LMLN Squint Club 2006 PAN Prolonged in- office exam - check AHP while talking to parents for PAN [show age appropriate DVD]
FAT scan to determine consistency 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 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] Squint Club 2006 When to record and why record eye movements for nystagmus diagnosis? Does everyone with wiggly eyes need to be recorded? Usually - not if youre 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? Squint Club 2006 What if youre not sure? CN waveforms are unique can confirm diagnosis
Can save patient expensive imaging studies (esp. small children) Squint Club 2006 What if youre not sure? What distinctions can you make? Acquired vs. cong types N CN vs. cong PAN CN vs. LMLN
N vs. saccadic oscillations 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 Squint Club 2006 Latent nystagmus EMR often required to determine whether LN is due to
CN or LMLN The eye eye is quicker than the Squint Club 2006 Assessing effects of treating CN CNs 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 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 Squint Club 2006 Modern Treatment Options In congenital Nystagmus
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 Squint Club 2006 Treatment goals in CN 2
Normalize head posture Prisms Surgery Broaden NZ to expand effective visual field Prisms CLs Surgery Squint Club 2006 Medical treatments
Drugs - barely explored New epilepsy drugs Lyrica, Memantine, Neurontin 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 Squint Club 2006
Contact lenses VA optical effect alone CL sometimes expands NZ & improves foveation time ? Stimulates conjunctival proprioceptors DellOsso 1988. Contact lenses and congenital nystagmus. Clin. Vision. Sci. 3:229-232 Squint Club 2006 Surgical treatments #1: ARTIFICIAL DIVERGENCE #2: KESTENBAUM / ANDERSON #3: HERTLE TENOTOMY
#3A: 4 MUSCLE RECESSION #4: LMLN SURGERY Squint Club 2006 #1: ARTIFICIAL DIVERGENCE SURGERY Cuppers,1970s. Popularised by Spielman 1990s. >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 Squint Club 2006 ARTIFICIAL DIVERGENCE SURGERY
COMPLICATIONS AND EXPECTATIONS 10% consec XT Improved VA & field Decreased AHP & nystagmus BEST OPERATION FOR NYSTAGMUS Squint Club 2006 #2: HORIZONTAL NULL POSITION SURGERY KESTENBAUM / ANDERSON
50y history! Rc/Rs OU for face turn 13mm OU for 15 - 25 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 Taylors grandfather 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 Squint Club 2006 Non- specific +ve effect of CN surgery Kbaum operation usu: Expanded null zone * Improved acuity ** IRRESPECTIVE of whether the
KBaum 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 Squint Club 2006 Intriguing Question Does Kbaum surgery have a
non-specific +ve effect that we can exploit ? 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] Squint Club 2006 Lakota Copper Squint Club 2006 #3: HERTLE TENOTOMY OPERATION
If Kbaum 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 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 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 80s Reinecke improves VA only in PAN Squint Club 2006
4. Surgery for LMLN Reinecke Corrrect ET or XT perfectly and convert LMLN to LN Improved face turns Improved VA Squint Club 2006 Audit of EMR: How EMR can help diagnosis and treatment of patients
with nystagmus Audit methods Files of 79 LK private patients with presumed cN reviewed 55 patients had EMR Recordings and clinical diagnosis were compared Squint Club 2006 The population studied
15% 6% 59% 20% CN LMLN CN and LMLN Other (including APAN)
EMR indeterminate 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 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
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
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
Squint Club 2006 Limitations of EMR THANK YOU LARRY! 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 Squint Club 2006 Accuracy of clinical signs 100
90 80 70 60 50 40 30 20 10 0 1. Conv. Null in2. Jerk to gaze1. & 2. combinedEcc. Null in CN Jerk to fixn CN dir.
Sensitivity Specificity 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 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
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
Squint Club 2006 SURGERY IN CONGENITAL NYSTAGMUS 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] 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 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 Squint Club 2006 Strabismus + Hertle n=6 1/6: fixation switch : problems 1/6 PAN. E + conv null for D
confirmed with glasses. Sx: NO effect on FT. 2nd surgery to augment BMR - some improvement 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* : 2nd op to advance one MR Alt FTs much improved * +ve Kappa of OCA makes this look worse 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 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 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 Squint Club 2006 Summary : Effect on AHP
Any sensible surgery usu effective for AHP in CN and PAN 9/12 : improved AHP 5 require 2nd op 3 were for residual / induced strabismus 2 required 2nd op to improve residual AHP
Squint Club 2006 Summary Effect on oscillopsia Excellent 2/2 with resolution of symptoms Squint Club 2006 Becoming an expert Read
the following authors: 1. Hertle 2. Reinecke 3. Spielman 4. Abadi 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 isnt impressed. The snail thinks its fantastic!* * Tychsen Squint Club 2006 LAST SLIDE!! THANK YOU FOR YOUR TIME AND PERSEVERANCE Squint Club 2006
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) & noncoital 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.
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