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160 Cards in this Set
- Front
- Back
What region of the world is exotropia most common?
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near the equator
|
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Age of onset for exotropia
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35-70% in first 3 years of life
|
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______% of XT are intermittent
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85
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How can you determine if XT is constant or intermittent?
|
check stereo!
if they have it, it is not constant |
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T/F Amblopia is very prevelant in cases of XT
|
FALSE
usually intermittent |
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T/F In XT, the likelihood of AC is low
|
T
|
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_____% of XT ave a vertical compeontnt
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16-52%
|
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33% of pts with XT have _________ by age 5
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overaction of inferior oblique
|
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A pattern of vertical deviations is due to
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overaction of SO
in down gaze, the 2 eyes are more exo |
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V pattern of vertical deiation is due to
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overaction of IO
in up gaze the two eyes are move exo |
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T/F In children XT is usually comitant
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T
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T/F Infntile XT associated with increased likelihood of neurological problems
|
T
|
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T/F Adult onset XT is unlikely to be neurological
|
FALSE
|
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T/F Infailte Exotropia is very rare
|
T
unless craniofacial abnormality or neuro deficits are present (Aperts Syndrome or Krouzon's) |
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Age of onset for infanitle exotropia
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within first year of life
|
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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?
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withing +/-3.50D
low astigmatism if present |
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Common ocular motor abnomralities found in infanitle XT?
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Dissociated vertical deviation (During PRIMARY gaze)
Overaction of inferior oblique and SO common (ONLY in 2ndy GAZE!!) |
|
Treatment of Infantile EXotropia?
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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 |
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Intermittent XT makes _______% of all strabismus
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25
|
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T/F Divergence excess XT is more common in younger children
|
T
|
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T/F Convergence insufficiency XT is seen more in children than adults
|
FALSE
seen in adults an older children |
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Typically we do not get AC with intermittent strabs but _ are exceptions
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intermittent XT
if developed young --? suppression |
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If you see a constant, unilateral XT it is due to __ until proven otherwise
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disease
|
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3 types of intermittent exotropia
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Divergence excess XT
Basic XT CI CT |
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Divergence excess XT have _______ AC/A
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HIGH
|
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In DE XT, the deviation is larger where?
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DISTANCE t han near by 10 pd!!
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Wat type of XT is present in DE?
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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 |
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In BASIC exo what is the angle at D and near?
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it is the same or similar etween 15--2opd
usually intermittent XT and alternating NORMAL AC/A |
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T/F Basic XT have LOW AC/A
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FALSE
NORMAL |
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With CI XT, where is the angle greatest?
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GREATER at NEAR than DISTANCE by at least 10 pd
10 or less at distance 10-25 pf at near |
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What is the AC/A ratio for pts with CI XT?
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LOW!
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Signs of CI XT?
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intermittent and alteranting
receded PC and LOW PFV at near (BO) normal RE |
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What is the definition of non-comitant deviation?
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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 |
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___________ have muscle under-actions or and over-actions
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non-comitant deviations
|
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Etiology of non-comitancy
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faulty muscle to due to injury
mechanical restrictions: Brown's Tendon Syndrome, Duane's Sheath Innervational (pareisis/aralysis) |
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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 |
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What is Herring's Law of Equal Innervation
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when an impulse for an eye movement is sent out, CORRESPONDING muscles of each eye receive equal innveratio to constract or relax --> yoked muscles
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If a paretic eye fixates, what happens to the other eye?
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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. |
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THE magnitude of SECONDARY angle is bigger if you fixate with the ______ eye. The secondary angle is ALWAYS ______ than the primary angle.
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PARETIC
larger |
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If you see over-action in primary gaze what muscles must be responsibel for this
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IO or SO
|
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congential onset of non-comitant strab?
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before 6 months of age
view baby photos to see turning of head to avoid diplopa from infancy |
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Remember Muscle actions:
oBliques |
aBduct
|
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Do Superior muscles intort or extort?
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INTORT
S IN. |
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Do Inferior muscles extort or intort?
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EXTORT
|
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fill in the blank
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Adduction
|
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fill in blank
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Abduction
|
|
fill in blanks
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elevation intort adduction
|
|
fill in blanks
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depression
extort adduction |
|
fill in blanks
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incyclo
depression abduction |
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fill in blanks
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extort
elevation abduction |
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Muscle agonist definition:
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the muscle responsible for moving eye into desired position of gaze. The agonist of moving te right eye to the righ ti sthe RLR
|
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Muscle antagonist definition:
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muscle that oves the eye in the othe opposite direction of the desired position of gaze. The antagonist to the RLR os the RMR.
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Homolateral synergist=
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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)
|
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Contralateral synerists=
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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.
|
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Contralateral synergists form ______-muscles
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YOKED
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Whenever an impulse for an eye movement is sent, yoked muscles receive _______ to cotnract or relax
|
EQUAL innervation
|
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1 degree angle of deviation is determined when _________-
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the good NONparetic eye fixates
|
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2 degree angle of deviation is determiend when the
|
pareit eye fixates
|
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T/F 2 degree angle is ALWAYS greater than 1 degree angle
|
T
|
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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
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RSO
|
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if pt is an exo and tilts head to the right, its a ____ palsy until proven otherwise
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LSO
|
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What is the doll head phenomena?
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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.
|
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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. |
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If pt has RIO paresis, what will pt do to compensate?
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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 |
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% of functional cure for intermittent XT?
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85%
|
|
Decompensated Exotropia definition
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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 |
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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
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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
|