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160 Cards in this Set

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What region of the world is exotropia most common?
near the equator
Age of onset for exotropia
35-70% in first 3 years of life
______% of XT are intermittent
85
How can you determine if XT is constant or intermittent?
check stereo!
if they have it, it is not constant
T/F Amblopia is very prevelant in cases of XT
FALSE
usually intermittent
T/F In XT, the likelihood of AC is low
T
_____% of XT ave a vertical compeontnt
16-52%
33% of pts with XT have _________ by age 5
overaction of inferior oblique
A pattern of vertical deviations is due to
overaction of SO

in down gaze, the 2 eyes are more exo
V pattern of vertical deiation is due to
overaction of IO
in up gaze the two eyes are move exo
T/F In children XT is usually comitant
T
T/F Infntile XT associated with increased likelihood of neurological problems
T
T/F Adult onset XT is unlikely to be neurological
FALSE
T/F Infailte Exotropia is very rare
T


unless craniofacial abnormality or neuro deficits are present (Aperts Syndrome or Krouzon's)
Age of onset for infanitle exotropia
within first year of life
How large is the deviation in Infantile XT?

Is it Constant or Intermmittent?
Is it Alternating?
Is Amblyopia likey?
LARGE deviation 30-60 pd

Constant strab, therefore -RDS

Alternation is COMMON--> thus amblyopis is NOT likely
What is the RE of infantile XT?
withing +/-3.50D

low astigmatism if present
Common ocular motor abnomralities found in infanitle XT?
Dissociated vertical deviation (During PRIMARY gaze)
Overaction of inferior oblique and SO common (ONLY in 2ndy GAZE!!)
Treatment of Infantile EXotropia?
rule out retinal or neuro
poor prognosis for functional cure
treat any sig RE
treat amblyopia if present
REFER FOR SURGERY before 18 months --> will have bilateral lateral rectus recession

Goal: get within 10 pd of ortho

80% cosmetic cure
Intermittent XT makes _______% of all strabismus
25
T/F Divergence excess XT is more common in younger children
T
T/F Convergence insufficiency XT is seen more in children than adults
FALSE

seen in adults an older children
Typically we do not get AC with intermittent strabs but _ are exceptions
intermittent XT

if developed young --? suppression
If you see a constant, unilateral XT it is due to __ until proven otherwise
disease
3 types of intermittent exotropia
Divergence excess XT
Basic XT
CI CT
Divergence excess XT have _______ AC/A
HIGH
In DE XT, the deviation is larger where?
DISTANCE t han near by 10 pd!!
Wat type of XT is present in DE?
intermittent and alternating --> amblyopia is not likely

see normal RE
CLOSURE of one eye in bright light

Have deep suppression at distance and OCCASIONAL AC
In BASIC exo what is the angle at D and near?
it is the same or similar etween 15--2opd

usually intermittent XT and alternating

NORMAL AC/A
T/F Basic XT have LOW AC/A
FALSE

NORMAL
With CI XT, where is the angle greatest?
GREATER at NEAR than DISTANCE by at least 10 pd

10 or less at distance
10-25 pf at near
What is the AC/A ratio for pts with CI XT?
LOW!
Signs of CI XT?
intermittent and alteranting
receded PC and LOW PFV at near (BO)
normal RE
What is the definition of non-comitant deviation?
strab differs by more than 5pd in different directions of gaze at ONE VIEWING DISTANCE (D OR N); can be a phoria or strab

DO NOT COMPARE D to N
___________ have muscle under-actions or and over-actions
non-comitant deviations
Etiology of non-comitancy
faulty muscle to due to injury
mechanical restrictions: Brown's Tendon Syndrome, Duane's Sheath
Innervational (pareisis/aralysis)
Muscle under-actions:
affects the muscle itself or its input: mechanical disorders due to muscle insertions, adesions, orbit shape,

innervational distrubances CN 3,4, or 6
What is Herring's Law of Equal Innervation
when an impulse for an eye movement is sent out, CORRESPONDING muscles of each eye receive equal innveratio to constract or relax --> yoked muscles
If a paretic eye fixates, what happens to the other eye?
OVER-action of its uoked muscle will occur because of the excesive innervation required of the pareit c eye= secondary angle.

THE magnitude of SECONDARY angle is biggger if you fixate with the PARTIC eye. The secondary angle is ALWAYS larger than the primary angle.
THE magnitude of SECONDARY angle is bigger if you fixate with the ______ eye. The secondary angle is ALWAYS ______ than the primary angle.
PARETIC


larger
If you see over-action in primary gaze what muscles must be responsibel for this
IO or SO
congential onset of non-comitant strab?
before 6 months of age

view baby photos to see turning of head to avoid diplopa from infancy
Remember Muscle actions:
oBliques
aBduct
Do Superior muscles intort or extort?
INTORT

S IN.
Do Inferior muscles extort or intort?
EXTORT
fill in the blank
Adduction
fill in blank
Abduction
fill in blanks
elevation intort adduction
fill in blanks
depression

extort

adduction
fill in blanks
incyclo

depression

abduction
fill in blanks
extort

elevation

abduction
Muscle agonist definition:
the muscle responsible for moving eye into desired position of gaze. The agonist of moving te right eye to the righ ti sthe RLR
Muscle antagonist definition:
muscle that oves the eye in the othe opposite direction of the desired position of gaze. The antagonist to the RLR os the RMR.
Homolateral synergist=
muscles in the SAME eye that have the SAME action (RSR and the RIO BOTH elevate the eye, and RSR and RSO both intort the eye)
Contralateral synerists=
muscles in opposite eye that have the SAME action (RSR and LIO oth elevate eye up) Contralateral synergists form YOKED muscles. The RSR and the KIO are yoked muscles that both elevate the eyes in the same directio nof gaze.
Contralateral synergists form ______-muscles
YOKED
Whenever an impulse for an eye movement is sent, yoked muscles receive _______ to cotnract or relax
EQUAL innervation
1 degree angle of deviation is determined when _________-
the good NONparetic eye fixates
2 degree angle of deviation is determiend when the
pareit eye fixates
T/F 2 degree angle is ALWAYS greater than 1 degree angle
T
Describe contracture of homolateral antagonist (overaction)
Normally, when a muscle acts to move the eye, it contracts (shortens) and its antagonist lengthens.
If a muscle is paretic, then it no longer contracts fully. Its antagonist, therefore, does not lengthen and stays in a state of contraction (shortened muscle). This constant over-action leads to a loss of elastic tissue = contracture.
Occurs when the “sound” eye fixates.
Contracture of the Contralateral Synergist--example
RSO paresis causes contracture of the LIR if the patient is fixating with the right eye. WHY?
Because it takes excessive innervation to stimulate the right eye to look down and to the left, the LIR receives this same innervation and contracts too much. Over time, this continual contraction causes a loss of elasticity to the LIR and it is unable to lengthen.
Contracture of the Contralateral Synergist (yoked muscle) defintion
A yoked muscle receives as much innervation as the agonist. When a paresis is present and the patient fixates with the paretic eye, both the agonist and its yoked muscle receive excessive stimulation. The muscles do not lengthen. Over time, this over action causes contracture (loss of elasticity)
Occurs when the paretic eye fixates.
Inhibitional Palsy of the Contralateral Antagonist
The antagonist of a paretic muscle requires less than normal innervation to move into its field of action.
The yoked muscle of the antagonist will therefore also receive less stimulation and will therefore under-act and appear palsied.
This phenomenon occurs ONLY WHEN THE PARETIC EYE FIXATES!!!!
How soon does inhibitional palsy of contralateral antagonist come into play?
can occur almost immediately, wthin hours.

The anatagonist of the paretic muscle requires less than normal inervation to movei nto its filed of action. The yoked muscle of the antagonist will therfore also receive less stiulation and will therefore underact and appear palsied. ONLY currs when paretic eye fixates
Example of inhibitional palsy of contralateral antagonist:
RSO paresis
Patient fixates with right eye and looks up and to the left (the DAF of the RIO).
Because the RSO is paretic, (its antagonist) the RIO needs less innervation to move up and left.
The yoked muscle of the RIO, the LSR, therefore also receives less innervation.
This results in the appearance of a LSR palsy when looking up and left.
A normal eye appears paretic!!!
if pt is an exo and tilts head to the left its a _____ palsy until proven otherwise
RSO
if pt is an exo and tilts head to the right, its a ____ palsy until proven otherwise
LSO
What is the doll head phenomena?
the FACE is always placed in the diagnoistc action field of the affected muscle in an attempt to avoid diploia and maintain binocular ision field. The EYE moves away from the muscle field.
If pt has a RSO paresis, what will pt do to compensate?
tilt chin DOWN and turn face LEFT


RSO is responsible for moving eyes DOWN and INTORT. If RSO doesn't work, your face will move down instead (chin down) and move your face to the left and tild so that your eye looks in without having to intort it.
If pt has RIO paresis, what will pt do to compensate?
Face turn left, chin up, head tilt right

RIO makes pt look up and out. If pt cannot do that, they will move face up and to the left, and tilt to the RIGHT!
Treatment for intermittent XT
correct RE
add minus lenses for pts too young to do VT
NEVER occlude constantly because it can cause an intermittent strab to be constant
Use BI prism (partially correct pt, 10 pd BI for a 20 pd XT intermittent--> Give for basic XT, since same for D and N)
VT for PFV

surgery if larger than 20pd
% of functional cure for intermittent XT?
85%
Decompensated Exotropia definition
an intermittent or cosntant XT which used to be an XP, PFV and accomdoative convergence ranges are no longer able to compensate.
Decompensated XT cinical eval
recent onset of diplopia
may be worse at Near
comitant-> most test in 9 position of gaze
can be intermittent or constant
Treatment of Decompensated XT
correct RE
consider prism, usually a fresnel, give the lowest amount to see 4 dots on Worth4dot.

VT to increase PFV

if angle is still greater than 20 after VT, consider surgery

Deviation SAME at D and N!
T/F you CANNOT perform surgery on a CI XT
T!
surgery will make this pt eso at distance!
2 Types of secondary exotropia
sensory XT

Consecutive XT
Clinical findings of sensory XT
XT is LARGE 30-60 pd

Constant and unilateral

Amblyopia is possible!!

Associated with hyperdeviation OIO or OSO

want to treat cosmesis
Surgery should be performed withing TWO years of injusry to avoid possibility of intractable diplopia.
What is Spontaneous XT?
may occur in pts who have more than 4.50D of hyperopia with ESOtropia!

XT occurs with full RE IN PLACE
__________ is the best test used for non-comitant deviations with recent onset
hess lancaster
What must be ruled out before doing the Hess Lancaster test?
AC


most non-comitant deviatiosn do not have AC
T/F Hess Lancaster is an OBJECTIVE test
FALSE

SUBJECTIVE
Which light determiens the fixating eye during the Hess Lancaster test?
examiner's light

Pt light determines the muscle field

EACH block represents 7 pd at 1 meter
Explain Hess Lancaster test
when examiner uses green light and makes pts OS fixate, the OS is forced to reach each of the 9 positions on the screen, THUS OD muscle action is meaasred and plotted via Herrings law.

This is a direct projection

then the pt and dr switch flashlights to repeat procedure and plot OS muscle field
How do you analyze the results of the Hess Lancaster test?
Analysis
Find plot with smaller field
Find greatest deviation from normal
Identify muscle(s) at fault
For each under-action there should be an overaction in the same DAF of the opposite eye (in non-comitant paretic deviations)
What does this Hess Lancaster result mean?
INFERIOR OBLIQUE PARESIS

first find the field with the SMALLER plot (right field)
then find the BIGGEST difference between two points (IO)

Thus its a RIGHT inferior Oblique paresis

(Notice the OVERACTION due to herring's law on the left side)
wHAT DOES this Hess Lancaster result mean?
A pattern ESOTROPIA
____________ test works est for recent onset, noncomitant strabs within 6 motnhs of onset
Red lens or Red glass test
What 2 questions do you ask pt during red lens test?
where is diplopia greatest?

Which light is MOST farthrest away from center to the pt?

The position of GREATEST diplopa identfies 3 possible muscles.

the most DISTAL light identifies the problem eye.

example: diplopia is worse in RIGHT gaze (RLR or LMR).
Red lens is FURTHEST away (means the RIGHT eye is the problem eye)
RLR problem
What does this result from Red lens test mean?
Diplopia is greatest on RIGHT gaze ( RLR or LMR)

RED light is farthest away! (RIGHT EYE PROBLEM)

Thus its RLR
What does this Red Lens test result mean?
RSR problem!!

Diplopia was worse up and to the right (either RSR or LIO)
R lens is furthest away, so its right eye is deviationg
THEREFORE" RSR problem --> muscle is underacting so the eye is hypo and right light seen aboe green
The Hess Lancaster test is recored according to the ______ view and the red glass test to the _______ view
patient's

examiner's
What is Park's Three Step good for testing
ONly VERTICAL deviations:phorias and tropias
What is the most common cause of vertical deviations? (90%)
Superior Oblique Paresis

assume vertical deviation is due to SO problem until proven otherwise

congenital 30-65% of the time

more acquired cases are due to head trauma
The vertical deviation seen in a superior oblique paresis is in _______ gaze
primary

devation is WORSE in adduction of paretic eye, worse at near, worse in down gaze and worse wen tiling to the SAME side as paretic eye
In SO paresis:
devation is WORSE in adduction of paretic eye, worse at near, worse in down gaze and worse wen tiling to the _____ side as paretic eye
SAME
Treatment of SO paresis
referral for medical workup to rule out pathology

prevention of secondary contractures by ALTERNATING occlusion full time
if given prism, must doe EXCURSION eye movements twice a day (prism for deviations under 10 pd in primary gaze, give fresnel and slpt if more than 5pd)
Vision therapy
compesnatory head posture teaing
T/F congential SO paresis will NOT have diplopia
T

will have compesnatory head posture
can do surgery if pd larger than 15
A _______ paresis ends up as a non-comitant ESOTROPIA
lateral rectus paresis

face turned towarded affected side

Diplopia WORSE at distance, ET worse at distance

usually a systemic issue
Lateral rectus paresis has diplopia worse?
at DISTANCE

ET is worse at distance
Treatment of Lateral Rectus paresis?
referral to neuro-opthalmoloist
prevention of secondary contracture with alternate occlusion and ecsursion eye movements
Fresnel prism if strab persists for >6months, consider surgery for >15pd.
NO driving allowed
A complete Third nerve paresis cuases the eye to appear how?
DOWN and OUT with fixed dilated pupil, droopy lid, and decreased accomodation.

If pupil is involved, refer to ER
superior division of third nerve is responsible for?
superior recti and levator. If effected, eye is down, pupil is spared, droopy lid
inferior division of third nerve is responible for?
inferior recti, inferior oblique, medial recti, and ciliary body

eye is exo, blow pupil and intorted
CN 3 mimickers=
thyroid eye disease
MG
Duane's
Brown's
mechanical restrction
congenital absense of muscle
T/F A congential third nerve paresis generally has NO compensatory head position
T

see deep amblyopis from constant strab and ptosis

No double vision so therfore pt is suppressing and no need for change in head posture
Treatment of congeital CN III paresis
treat anisometropia, correct RE and protect g ood eye
Treat amblyopia
check for suppression or diplopia
refer for surgery for ptosis or for strab
Treatment of aquired CN III paresis
refer for complet medical work-uo
most go away in 3-6 months
Do alternate occlusion if deviation is >20pd to prevent contractures
As it improves, use Fresnel prism
Always do daily large ecsursion eye movements to prvent contracture
NO driving
______ syndrome: limitation of adduction, abduction, or both. Glove reatraction and narrowing of palpebral fissure on adduction The eye pulsl back into its socket as you attempt to adduct
Duane's

Vertical deviations and up/down shooting on adduction

typically unilateral
Which EYE is more affected in Duane's?

T/F Duane's effects males more than females
LEFT eye more affected

FALSE
FEMALES more affected
Most common type of Duane's?
Tye 1

abduction deficit
ESO in primary gaze is SMALLER than when you try to abduct! (eso worse when abducting)
Describe Duane's Type II
Adduction deficit
EXO in primary gae INCREASES with adduction!!
Describe Duane's Type III
EXO deviatio during Adduction
ESO deviation during ABduction
How do you treat Duane's?
surgery is needed for large eso >15 pd in primary gaze

prism can be used to minimise when <15 pd
What eye and who is usually affected in Brown's?
RIGHT eye

Female
Findings of pt with Brown's?
HYPOtropia on ADDuction
Eyes move DOWN as pt adducts

limited elevation od adduction

Get a POSITIVE forced duction test, both versions and ductions are restricted

SO muscle is trapped
How to differentiate between Brown's and IO paresis?
in Browns:
NO hypoin PRIMARY gaze
NO overaction of homolateral SO
NO head tilt
Ductions and versions are the same
____________:a spontaneous upward deviatio nof one or both eyes when pt is fatigued, daydriming, inattentive, or when fusion is disrupted
dissociated vertical devation

onset usually less than age 3
often associated with infantile ET

CAN improve with time
T/F Patients with DVD may improve with time
T

is treatable. Only treat if not latent.

If latent, then no treatment.
An overaction of the ________causes an elevation of the eye in aDDUCTION
Inferior Oblique


(see it in SECONDARY gaze OJNLY)
In OVERaction of the Inferior Oblique muscle, what do you see in PRIMARY gaze?
NO to MINIMAL vertical deviation. ONLY occurs in secondary gaze.


REMEMBER: DVD occurs in BOTH primary and secondary gaze
While Overaction of inferior oblique only occurs in secondary gaze, ________ occurs in BOTH primary and secondary
DVD
A ____ pattern deviation is often associated with inferior oblique overaction
V pattern

EXO is WORSE in upgaze


(so when you look IN, eyes are UP. When you look UP, eyes are OUT)
An overaction of the __________ occurs with a DEPRESSION of the eyes on ADDuction
superior oblique

REMEMBER, overaction is ONLY seen in SECONDARY gaze

onset is usually below 4 yrs of age
Often associated with a LARGe magnitude of exotropia
Overaction of Superior Oblique is assoicated with a ___ pattern exotropia, with exo being worse in ___ gaze
A pattern

DOWN gaze
T/F Overaction of the Superior Oblique is associated with neurologic disorders
T
hydrocephaly
cerebral palsy
mengiomeolocele

BE concerned with these pts
When testing A and V Pattern Strabismus are testing at ___ derees of upgaze and _____ degrees of downgaze
25

35
both A and V pattern deviations are due to
overaction of muscles
T/F With overactive muscles, Symptoms occur MORe frequently if the deviation is LARGER in DOWNgaze
T

since we READ in downgaze, pts are more likely to recognize a problem than in upgaze
With A pattern eSotropia, esotropia is greater in UPgaze by _____ or more compared to downgaze
10 pd
With A pattern eXotropia, the exotropia is greaterr in DOWNgaze by ___ pd or more compared to upgaze
10 pd
With V pattern deviations, esotropia is worse in ____ by 15 pd or more
downgaze
With V pattern deviations, eXotropia is worse in ____ by 15 pd or more
upgaze
What is myasthenia Gravis?
a neuromuscular disorder of voluntary STRIATEd muscles caused by the fai;lure to produce or rlease acetlycholine at nmj --> causes weakness and fatigue of mucles
_______% of all MG patienst presnt with ocualr symptoms
50
What is the most common ocular restriction in pts with MG?
upgaze restriction is the most common diplopia when looking up

mimmics CN3 superior dvision paresis, however this is intermittent diplopia while CNIII would be constant
What must you rule out in all recent onset strabismuses?
MG
Normal BI and BO vergences for distance?
BI=x/7/4
BO= 9/19/10
How do you prevent secondary contractures
alternating occlsuion, ocular calisthenics
____ is a condition in which PERIPHERAL fusion and vergence amplitudes are capable of maintaining ocular aligment within approximately 10 pd of ortho DESPITE stereo deficiency and central macular suppression scotoma in one eye during binocular viewing
Monofixation syndrome
What will a pt see on W4D test if they have monofixation?
4dots at near, and at distance it falls into suppression scotoma
Diagnosis of monfixation syndrome
-lack of symptoms deviation
under 10 pd
-alternate CT may be larger than unilateral CT (less than 10 pd)
-NO suppression scotoma seen under MONOCular conditions, but seen during inocular onditions
-Contour stereo is PRESENT but reduced

-will NOT have RDS
What 3 ways can you diagnose of suppression scotoma
1. Worth 4 Dot (suppression at distance only)
2. Bagolini Striate Lenses- a gap in the streak of light is seen by the deviaed eye under binocular viewing
3. 4BO Test performed at distance: ONLY objective TEST. pt is not suppressing if you see a version movement followed by a vergence movement,. If scotoma is present, NO recovery vergence movement occurs
How can you differentiate between a macular lesion from monofixation syndrome?
monofixation syndrome scotoma is ONLY present at distance and ONLY under binocular conditions.

Macular lesion suppression scotom is present during monocular AND binocular conditions
Treatment of monofixation syndrome includes antisuppression therapy=
monocular in binocular field
__________:a small angle strab which develops EF equals to the amount of the strabismus. The amount of EF is equal to the true objective angle.
Microtropia.

Do not see movmeent on unilateral cover test
Age of onset for microtopria?
RDS present?
How embedded is their HAC?
less than 3

NO RDS since pt is not bifoveal, can get reduced contour stereo

DEEPLY embedded HAC
T/F
ALL microtropes are monofixators
T!!

BUT not all MONOFixators are microtropes
Qualifications for surgery:
____ pd or larger esotropia
____ pd or larger exotropia
____ pd or larger hypertropia
15
20
10
What is the MOST common surigcal procedure for strabismus?
Loosening=recession
muscle is cut from the globe and re=attached morer posteriorly to increas slack in muscle and decrease effective pulling power.

ONLY reversible method
Transposition surgery is for what kind of strabs?
cyclovertical
DVD's and OIOs
For pts with esotropia, what kind of surgery is performed?
medial rectus recession
For pts with exotropia what kind of surgery is performed?
lateral rectus recession
Benefits of surgery=
___% cosmetic
___% need ADDITIONAL surgery
80%
20%
Atropine is used to treat _______
Echothiophate iodine is used to treat ___-
amblyopia

accomodative ET
Nono-comittant deviations usually go away in _______ days and are only worse in one position
60-90
T/F The Larger the magnitude angle, the more difficult is to treat patient
FALSE

smaller the angle (microtropia is harder to treat than LARGE exos, for example_
For an intermittent pt, the success rate for a cure is
functunal or almsot cure is 96%

if CONSTANT it drops to 64%
Most common cause of vertical deviations (90%)
Superior Oblique Palsies