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86 Cards in this Set

  • Front
  • Back
Clinical Model of Visual Processing: 3 Major areas of Visual System?
What kind of deviation is a strabismus?
manifest deviation
Prism dioptor amount of deviation that qualifies as a strab?
deviation of the primary lines of sight of 1 prism D or more
Are Strabs constant or intermittent?
Either one. The lines of sight of the 2 eyes are not directed toward same fixation point
Amblyopia...unilateral or bilateral?
Usually unilateral...infrequently bilateral
Is amblyopia correctable by refractive means?
Amblyopia is associated with what things?
form deprivation, strabismus, anisometropia, other ambliogenic refractive errors
Definition of amblyopia?
Unilateral, sometimes corrected VA poorer than 20/20 in absence of obvious structural anomalies or ocular dz
Prevalence of Strabs?
or 5-15 million in US
Higher incidence of Strabs found?
in affected families (23-70%)
% strab in preschool population?
Most common visual abnormality in children 6-17?
Amblyopia prevalence?
In the under-20 age group, what causes more vision loss than all trauma and ocular dzs?
The VAIS (Visual Acuity Impairment Study) found what to be the leading cause of mono vision loss in 20-70+ age group?
functional amblyopia
What is the age limit that amblyopia can be treated?
there is NO age limit
According to Birnbaum, is age a significant factor in amblyopia treatment success?
Strab/Amblyopia treatment can benfit patients in what ways?
allow single vision, better cosmesis, stereopsis, increase binoc field, give them a spare eye, increase VA when binoc. (binoc. summation), improved kinesthetic cues, reduce psycho. impact
4 components of normal binoc. vision?
anatomical, motor, sensory, integration
Components of Normal Binoc. Vision: Anatomical examples?
healthy sensory organs and visual pathways
Components of Normal Binoc. Vision: Anatomical anomalies?
Ocular Disease
Components of Normal Binoc. Vision: Motor examples?
Accurate mono. fixation of either eye and accurate bifoveal fixation
Components of Normal Binoc. Vision: Motor anomalies?
strabismus, nystagmus, vergence dysfunction
Components of Normal Binoc. Vision: Sensory examples?
sensory correspondence system organized about the fovea (fovea as the center), similarity of the final perceived ocular images
Components of Normal Binoc. Vision: Sensory anomalies?
refractive error, amblyopia, eccentric fixation, accomodative dysfunction
Components of Normal Binoc. Vision: Integration examples?
integrated neuromuscular coordination of both intra and extraocular neuromusc. systems and sensory unification of 2 ocular images
Components of Normal Binoc. Vision: Integration anomalies?
Aniseikonia, suppression, anomalous correspondence, horror fusionis, central fusion disruption syndrome
What is eccentric fixation?
talking about 1 eye by itself...eye points or focuses with new spot other than the fovea. You will measure reduced acuity
What is anomalous correspondence?
2 eye situation... fovea of one eye does not correspond with fovea of the other eye (mismatch)
What is horror fusionis?
Can't put images together (can't fuse images)
What is central fusion disruption syndrome?
brain doesn't want to see images together, images float on top of each other. Seen in head trauma pts.
What are the components of a Strab/Amblyopia Case History?
1. CC
2. S/S
3. onset
4. PEH
5. PMH
7. Goals
Strab common signs and symptoms?
covers one eye in bright sun,
head turns/tilts/tips,
blinking or rubbing eyes
Intermittent Strabs and large heterophorias often complain of?
Severity of asthenopia may depend on?
Ability of fusional vergence system
IF FVS is poor in an intermittent strab, what could happen?
they may progress to a constant strab (decompensated phoria)
The greater the frequency of a strab, the higher probabilty of?
sensory anomalies
The more sensory anomalies...the fewer the ___?
Characteristics of a strab without symptoms?
likely long-standing, has sensory adaptations--suppression, anomalous correspondence, may not recognize symptoms
In functional amblyopis, it's important to rule out what?
congenital or pathological causes
functional amblyopia is usually unilateral or bilateral?
Mostly UNILATERAL...but can be bilateral rarely-assoc. with high isoametropia or bilateral eccentric fixation
Congenital period range?
birth to 6mo-1yr
Acquired period range?
greater than 1 yr
According to Sondi, any XT or ET after what time periods is considered abnormal?
XT after 6 mo = abnormal
ET after 2 mo = abnormal
Which deviation is more predominant during development?
Exo deviation
Strab/Amblyopia: Acquired stage's 2 categories?
1. Early acquired (<5yo)
2. Late acquired (>5yo)
Sudden onset could be due to?
trauma or signal a life-threatening situation
Which has a better prognosis...intermittent or constant deviations?
intermittent onset
Early Onsets-you should think of what kind of adaptations/prognosis?
sensory adaptations and poor prognosis
For acute onset, think of what etiology first?
Parents have better sensitivity or specificity for identifying strabismus?
specificity...better at determining those who do not have an eye turn (99%)

*only 65% for sensitivity-those who DO have the eye turn

*only 50% ability to determine eye turn in kids less than 1 yo
incidence of pseudo-esotropia can be as high as?
attributes that can confuse paretns and make them suspect esotropia are?
flat, wide bridges and epicanthal folds. Also developmental period of poor binocular coordination.
Time between the onset and the treatment becomes more critical when?
when the onset is earlier
What is the transmission of strabismus most probably?
Some factors that may be responsible for strabismus are? (4)
1. high AC/A ratio
2. >1.50 D hyperopia
3. eso/exophoric tendency
4. poor vergence ability
situations that prompt early examination of offspring or younger sibling for strabismus?
1. Either parent has strabismus
2. older sibling has strab
3. FEH of strab, even if parent and sibling normal
4. Normal parents but between them = low vergence ability, and >1.50 D hyperopia
Risk factors for exotropia/esotropia? (4)
1. low birth weight
2. maternal cigarette smoking
3. increased risk for ESOtropia with increased maternal age
4. assoc. with neurogenic abnormalities, seizure states, CNS and skeletal system conditions
What is an important etiological factor in strabismus and amblyopia?
refractive status
50% of all amblyopia is caused by?
According to Chimonidou, 72% of children w/strabismus had?
Abnormal refractions
2 significant attributes related to developing ESOtropia and amblyopia?
1. >2.00 D hyperopia (increases strain on accom system)
2. >1.00 D anisometropia, any meridian
As you scope off axis, what happens to astigmatism vs. spherical power?
astigmatism increases...spherical power decreases
How does increased accomodation by the pt. affect (-) vs. (+)?
Increased accom. = artificially increases (-) and decreases (+)
When doing ret, if you see a sudden shift from "with" to "against" motion, what is happening?
the patient is accomodating
when should you consider out of phoropter refraction?
children and all deviations >15 pd
Noncycloplegic Static Ret is what kind of procedure?
ON-AXIS initial screening procedure
For Noncycloplegic Static Ret, what do you do with the prism? (mainly ET and vertical problems)
hold the correcting prism in front of the FIXATING eye. (eye looking at the E)--use neutralizing prism
Another name for Near Ret Method is?
mohindra working distance is?
50 cm
What is the method for Mohindra?
1. patient in chair or lap
2. 50cm WD
3. Room lights OUT
4. Pt fixates on Ret and monitor corneal reflex to make sure "on-axis"
5. Occlude one eye
6. Neutralize primary meridians
7. Subtract 1.25 from sph value
To agree with cyclop. ret, Saunders suggests what changes for children and infants?
Children = subtract 1.00 D
Infants = subtract 0.75 D
How does Noncycloplegic Static Ret affect Hyperopia?
it slightly underestimates Hyperopia
If you have poor confidence in Noncycloplegic Static Ret what should be done instead?
cycloplegic refraction
What drug is better suited for a cycloplegic refraction?

*NOT tropicamide = short duration, poor at eliminating high accom tonus of childhood
Cyclopentolate dosage?
<1 yo = 0.5% soln 2 gtts (1 gtt wait 5 min, add 1gtt)

>1 yo = same gtts but use 1% soln
Cyclopentolate response for nydriasis and cycloplege?
Mydriasis = within 30 min
Cycloplegia max = 30-45 min
Cyclopentolate duration for mydriasis and cycloplege?
Mydriasis = 24 hrs
cycloplege = 8-24 hrs
Cyclopentolate toxicity symptoms?
restlessness, aimless wandering, irrelevent talking, hallucinations, memory loss, faulty orientation to time/place
Atropine Dosage?
<1yr = 0.5% soln/ung BID x 3 days prior to exam

>1 yr = same except use 1%
Atropine Response for mydriasis and cycloplege?
Mydriasis = within 30-40min
Cycloplege = within 1 hr, max 3-6 hrs
Atropine duration for mydriasis and cycloplege?
Mydriasis = as long as 12 days
Cycloplege = 10-18 days
Atropine toxicity symptoms?
dryness of mouth ans skin, flushing of face, fever, tachycardia, irritability or delirium

*TX = physostigmine 0.25mg SubCut inj repeated q 15min until symptoms decrease
How do you determine adequacy of cycloplegia?
NPA = < 2D accomodative amplitude

Dynamic ret = +2.00 D lag or greater

Use single line of threshold Snellen @ distance. Add
-0.75, if this reduces VA, then cycloplegia is adequate
Is pupil size an indicator of adequate cycloplegia?
In cycloplegic refraction, how do you scope? How do you do it with an eye turn?
Still need to scope "on-axis"

Use prism or pt looks at ret light monocularly (Subtract WD!)