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19 Cards in this Set
- Front
- Back
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What is Lee's screen considered most useful for?
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- Dx and prog of paralytic and restrictive strabismus
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What does the small box represent? How many degrees ?
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central fixation, 15deg outside primary position
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How many degrees is the big box?
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30 deg outside centre
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explain how lees screen works
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- 2 identical screens 90 deg to each other
- double sided mirror at 45 deg dissociates patient - superimposes the 2 screens - pt sits directly in front of one screen with one eye looking thru mirror and other viewing screen in front |
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Is lees screen performed with or without correction?
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without
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which eye views the blank screen?
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deviated eye
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advantages of lees screen?
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- very fast (~ 5 min)
- reliable - provides a picture chart |
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disadvantages of lees screen?
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- sometimes too difficult or too big for kids
- expensive - not readily available - space issues |
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What is the main diff between lees and hess?
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lees - mirror complete dissociation
hess - red/gr glasses partially dissociate |
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how does hess screen work?
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pt holds green torch while goggles are switched to allow for fixing either eye
(red goes over fixing eye) |
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?advantages of hess screen
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- less costly than lees
- more readily available - easier to detect torsion |
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disadvantages of hess screen?
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- requires dark rm
- if reduced VA, may have trouble seeing small red target - takes longer |
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what is the lancaster red-green
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similar to non-automated hess
- pt wears red/gr goggles, test at 2m - examiner: red torch pt: green - |
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In lancaster red-green or hess, how can you account for fixing either eye
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switch the goggles.. duhh
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What is the most important thing to look for if you suspect a paresis from the lees screen?
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sequelae
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describe muscle sequelae.
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- u/a of agonist
- o/a of ipsi antagonist - o/a of contra synergist (yoke muscle) - u/a of contra antagonist (inhibitional palsy) |
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In the interpretation of a lees screen, what does the smallest box tell you>
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involved eye
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What is the classic "Doggy Ear" an indication of?
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Brown's Syndrome
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What is the classic "apple core" an indication of?
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Duane's Syndrome
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