1. EXOTROPIA

2. DR. LIONEL KOWAL FRANZCO, FRACS MELBOURNE, AUSTRALIA

3. 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

4. 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

5. 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

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

7. 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

8. 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

9. 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

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

11. 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

12. 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%

13. 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

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

15. 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

16. 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

17. 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

18. 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

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

20. 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

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

22. 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

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

24. 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

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