EXOTROPIA

DR. LIONEL KOWAL FRANZCO, FRACS MELBOURNE, AUSTRALIA

EXOTROPIA Kowal ETIOLOGY OF EXODEVIATIONS NOT A MIRROR IMAGE OF ESOTROPIA BALANCE OF FASCIAL FORCES IN ORBIT HARD TO QUANTIFY ANESTHESIA POORLY UNDERSTOOD ANATOMICAL FACTORS ORBITAL SHAPE LR TENSION MAY BE NORMAL ET: MR ALWAYS HIGH [ROSENBAUM] LESS RELIABLE SURGICAL RESULTS

EXOTROPIA Kowal ETIOLOGY OF EXODEVIATIONS NEED TO EXPLAIN ALL OF: CAUCASIAN : ET > XT ASIA : XT > ET JAPAN : CONV INSUFF COMMONEST XT POSSIBLE REASONS / ASSOCIATIONS > 25% CAUCASIAN NEONATES > +4 > 60% ADULT ASIANS MYOPIC ORBITAL SHAPE IN ASIANS

EXOTROPIA Kowal ETIOLOGY OF EXODEVIATIONS MOTOR FUSION  ’PROTECTS’ AGAINST XT REDUCED MF → MORE PRONE TO XT S:  VA ANY REASON e.g. AMBLYOPIA M: CYCLOVERTICAL ANOMALY MF > EXO : PHORIA MF = EXO: I/MITT TROPIA MF < EXO: CONSTANT TROPIA

EXOTROPIA Kowal ‘ STANDARD’ XT : D > N – WHY? MF : N>D - PROVIDES MORE ‘PROTECTION’ AGAINST NEAR XT & OTHER PROXIMAL MECHANISMS ARE ADDITIVE (TPF)

EXOTROPIA Kowal KUSHNER ARCHIVES 2-4/98, 2/99 NEW MINIMUM STANDARDS FOR EVALUATION OF XT TARGET ANGLE & SURGICAL DOSE DEPENDENT ON SEVERAL SUBTLE ASPECTS OF EXAMINATION

EXOTROPIA Kowal KUSHNER SCHEME 1 A. 20 ft EXAM & B. OUTSIDE TARGET EXAM & C. PATCH FOR 1 HOUR B,C : ½ PTS - XT ANGLE AUGMENTS  LARGER SURGICAL DOSE

EXOTROPIA Kowal KUSHNER SCHEME 2 ? DIVERGENCE XS (DX) C : PATCH 1 HOUR 80% of DX BECOME D = N →Simulated DX DX PERSISTS: CHECK WITH +3 FOR N TRUE HIGH ACA / TRUE DX

EXOTROPIA Kowal OTHER EXOTROPIAS 1.DXD 2.CONSECUTIVE XT 3. INFANTILE XT 4. CONVERGENCE INSUFFICIENCY 5. NEUROLOGICAL XT

EXOTROPIA Kowal DXD [RAAB, WILSON] D ISSOCIATED E X O D EVIATION LOOKS LIKE ‘UNILATERAL’ XT E.G.: RIGHT FIXATION : L EXO LEFT FIXATION : NO EXO Exclude: Uncorrected + LE & RMR UA “COUSIN” OF D.V.D ?SIMILAR NYSTAG BLOCKING MECHANISMS ALL : Smooth Pursuit Asymm / CONGENITAL STRAB MANY : PREVIOUS LR RESECT

EXOTROPIA Kowal CONSECUTIVE XT CIANCIA : 390 CASES CONG ET WEEK 1 : 90% ORTHO 10-28y follow up : 20% > 10∆ XT ** THAT AMOUNT OF MR RECESS → SUCCESSFUL EARLY ALIGNMENT EVENTUALLY → CONSEC XT IN 20%

EXOTROPIA Kowal CONSECUTIVE XT 1.MOTOR FACTORS SCAR REMODELLING / MIGRATION [LUDWIG] ALPHABET PATTERNS esp. A SUBSEQUENT GLOBE / ORBITAL GROWTH 2. SENSORY FACTORS MORE COMMON WITH HIGH + POOR PERIPHERAL FUSION

EXOTROPIA Kowal INFANTILE XT MIRROR IMAGE CONG ET EARLY ONSET “REGULAR” XT SYSTEMIC DISEASE esp. CNS

EXOTROPIA Kowal CONVERGENCE INSUFFICENCY MULTIPLE DIAGNOSTIC CRITERIA REMOTE NPC X’ XT N > D REDUCED NEAR BOFR MULTIPLE CLINICAL TYPES CHILDHOOD ADOLESCENT SENILE NEUROLOGICAL AWAITS RECLASSIFICATION AND IMPROVED UNDERSTANDING

EXOTROPIA Kowal NEUROLOGICAL XT ‘BREAKDOWN OF PRE-EXISTING PHORIA’ DANGEROUS DIAGNOSIS I.N.O. FIELD DEFECT all types POOR MOTOR FUSION TBI, PARKINSON’S +VE NEURONAL ANTIBODY C.P.E.O. MYESTHENIA

EXOTROPIA Kowal CORE SLIDE: DECIDING ON THRESHOLD FOR TREATMENT DELICATE / CAREFUL BALANCE BETWEEN : NATURAL HISTORY ADVANTAGES OF XT DISABILITY OF XT [DISABILITY ‘SCORE’] & ADVANTAGES OF R X MORBIDITY OF R X

EXOTROPIA Kowal SYMPTOMS SCORE UCLA : HOME 1.XT, EX’=O MANIFEST TIRED, INATTENTIVE 2.XT < 5/d 3.XT > 5/d EX’=O 4. ONLY OCCASIONALLY STRAIGHT

EXOTROPIA Kowal SYMPTOMS SCORE UCLA : OFFICE 1.COVER TEST TO BREAK→RAPID RECOVERY 2.RECOVERY AFTER BLINKING 3.BREAKS SPONTANEOUSLY

EXOTROPIA Kowal MELBOURNE XT SYMPTOM SCORE 1.POTS % OF TIME STRABISMIC ______x 10% = /10 2. M.E.C. /3 3.DIPLOPIA /2 4.OTHERS NOTICE IT /2 5.OTHER _____________ /2 _____ /17+ USUAL THRESHOLD 7-8

EXOTROPIA Kowal OTHER FACTORS TO REACH THRESHOLD GLARE SENSITIVITY ↓ DISTANCE STEREO BOTHERSOME AWARENESS OF XT [ADULTS] BINOCULAR BLUR

EXOTROPIA Kowal OTHER FACTORS TO REACH THRESHOLD BINOCULAR BLUR [La Roche] 12y old : I/MITT BLUR 2y ago : I/MITT M.E.C. & DIPLOPIA 5y ago : I/MITT MISALIGNMENT BEO : 20/25 EITHER EYE : 20/20 NOW SYMPTOMS OF Xs ACCOMMODATION 2y ago : SYMPTOMS OF EXO

EXOTROPIA Kowal CONCLUSION XT COMPLEX MORE TRAPS MORE DIFFICULT TO EVALUATE THRESHOLD FOR R X : DEPENDENT ON SYMPTOMS

EXOTROPIA Kowal VERTICALS IN XT E.G. XT 30, LH 6 EX’=0 8 CYCLOVERTICAL MUSCLES Vertical Fusion Range ± <3∆ → FRAGILE BALANCE c.f. HORIZ FR WITH LITTLE / NO ROOM FOR ERROR 15° HORIZONTAL MISALIGNMENT : VERTICAL IMBALANCE NO SURPRISE

EXOTROPIA Kowal THRESHOLD FOR TREATMENT SYMPTOMS DEFINE THE NEED TO R X SIGNS DEFINE HOW TO R X