EXOTROPIA

EXOTROPIA

DR. LIONEL KOWAL FRANZCO, FRACS

MELBOURNE, AUSTRALIA

EXOTROPIA

Kowal

ETIOLOGY OF EXODEVIATIONS

NOT A MIRROR IMAGE OF ESOTROPIA

BALANCE OF FASCIAL FORCES IN ORBITHARD TO QUANTIFY ANESTHESIA

POORLY UNDERSTOOD ANATOMICAL FACTORSORBITAL SHAPE

LR TENSION MAY BE NORMALET: MR ALWAYS HIGH [ROSENBAUM]

LESS RELIABLE SURGICAL RESULTS

EXOTROPIA

Kowal

ETIOLOGY OF EXODEVIATIONS

NEED TO EXPLAIN ALL OF:CAUCASIAN : ET > XTASIA : XT > ETJAPAN : CONV INSUFF COMMONEST XT

POSSIBLE REASONS / ASSOCIATIONS> 25% CAUCASIAN NEONATES > +4> 60% ADULT ASIANS MYOPICORBITAL SHAPE IN ASIANS

EXOTROPIA

Kowal

ETIOLOGY OF EXODEVIATIONS

MOTOR FUSION ’PROTECTS’ AGAINST XT

REDUCED MF → MORE PRONE TO XTS: VA ANY REASON e.g. AMBLYOPIAM: CYCLOVERTICAL ANOMALY

MF > EXO : PHORIAMF = EXO: I/MITT TROPIAMF < 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 DOSEDEPENDENT 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 HOUR80% of DX BECOME D = N →Simulated DX

DX PERSISTS:CHECK WITH +3 FOR N TRUE HIGH ACA / TRUE DX

EXOTROPIA

Kowal

OTHER EXOTROPIAS

1. DXD2. CONSECUTIVE XT3. INFANTILE XT4. CONVERGENCE INSUFFICIENCY5. NEUROLOGICAL XT

EXOTROPIA

Kowal

DXD [RAAB, WILSON]

DISSOCIATED EXO DEVIATIONLOOKS LIKE ‘UNILATERAL’ XT

E.G.: RIGHT FIXATION : L EXOLEFT FIXATION : NO EXOExclude: 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 ETWEEK 1 : 90% ORTHO10-28y follow up : 20% > 10∆ XT

** THAT AMOUNT OF MR RECESS → SUCCESSFUL EARLY ALIGNMENT

EVENTUALLY → CONSEC XT IN 20%

EXOTROPIA

Kowal

CONSECUTIVE XT1.MOTOR FACTORS

SCAR REMODELLING / MIGRATION [LUDWIG]

ALPHABET PATTERNS esp. ASUBSEQUENT 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 CRITERIAREMOTE NPC X’XT N > D REDUCED NEAR BOFR

MULTIPLE CLINICAL TYPESCHILDHOOD ADOLESCENTSENILE 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 RX

•MORBIDITY OF RX

EXOTROPIA

Kowal

SYMPTOMS SCORE

UCLA : HOME

1. XT, EX’=OMANIFEST TIRED , INATTENTIVE2. XT < 5/d3. XT > 5/d EX’=O4. 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% = /102. M.E.C. /33. DIPLOPIA /24. OTHERS NOTICE IT /25. 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 BLUR2y ago : I/MITT M.E.C. & DIPLOPIA5y ago : I/MITT MISALIGNMENT BEO : 20/25 EITHER EYE : 20/20

NOW SYMPTOMS OF Xs ACCOMMODATION2y ago : SYMPTOMS OF EXO

EXOTROPIA

Kowal

CONCLUSION•XT COMPLEX

•MORE TRAPS

•MORE DIFFICULT TO EVALUATE

•THRESHOLD FOR RX : 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 RX

SIGNS DEFINE HOW TO RX