XT Flashcards

1
Q

posterior embryotoxin

A

anteriorly displaced schwalbes line

-increased risk for glaucoma

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2
Q

how much does having a posterior embryotoxon increase someones risk for glaucoma

A

50%

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3
Q

axenfeld syndrome

A

posterior embryotoxin + glaucoma

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4
Q

Reiger’s anomaly

A

embryotoxin + glaucoma + iris atrophy

Axenfeld syndrome + iris atrophy

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5
Q

Rieger’s Syndrome

A

embryotoxin + glaucoma + iris atrophy + systemic problems

embryotoxin + glaucoma + iris atrophy + systemic

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6
Q

types of XT

A

infant
acquired
secondary
micro

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7
Q

acquired XT

A

acute

mechanical

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8
Q

secondary XT

A

sensory

mechanical

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9
Q

intermittent acquired XT

A

after age 6m
deviation present more when tired
50% have basic XT and the other 50% will have either convergence insufficiency or divergence excess

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10
Q

types of acquired XT

A

basic XT (equal D and N)
divergence excess
convergence insufficiency

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11
Q

infantile/congenital XT

A

large deviation of 30-80 that occurs prior to 6m of age. Because it is usually alternating, infantile usually does NOT lead to amblyopia, but it can result in a reduction iin stereopsis. Patient’s may have associated neurological problems, esp in cases of a constant infantile XT

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12
Q

acute acquired XT

A

occurs after 6m of age.

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13
Q

acute acquired XT

A

characterized by sudden onset, constant exodus deviation. potential etiologies include neurological issues, trauma, or a decompensated phoria

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14
Q

mechanical acquired XT

A

due to physical restriction of an EOM (type 2 Duanes, graves, etc). Patients will NOT have full versions due to the EOM restrictions

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15
Q

sensory XT

A

after age of 5; it is more common in adults with acquired vision loss in one eye, resulting in a loss of a stimulus to fuse. Treatment involves correcting the vision loss, if possible

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16
Q

consecutive XT

A

iatrogenic, secondary to over correction of an ET during strabismus surgery

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17
Q

micro XT

A

exo deviation of less than 10 PD that is usually undetectable with CT. Similar to micro ET, it is associated with small suppression scotoma that may be confirmed with a 4BO test. Very uncommon

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18
Q

treatment for intermittent, acquired XT

A

VT, BI, over-minusing the distance RX

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19
Q

prism for XT

A

BI

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20
Q

lenses for XT

A

more minus, increased accommodation, eyes turn in. Over minus best for XT
-be sure to look at AC/A

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21
Q

fusion and BV

A

3 bad in strabismus

  1. 2 clear images
  2. same size
  3. fall on corresponding retinal points
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22
Q

counteracting diplopia and confusion

A

the brain may suppress an image in the strabismic eye, or may develop ARC

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23
Q

ARC

A

a sensory adaptation that must develop before age 5. Only occurs under binocular viewing conditions. Under monocular viewing conditions, the deviated eye will use the fovea to fixate the target

the non foveal point in the deviated eye that is viewing the object becomes “linked” to the fovea of the fellow (non deviated) eye. The new ARC ensures that the object will be perceived in the same visual direction in each eye, thus eliminating diplopia and confusion

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24
Q

NRC

A

present when the fovea of each eye corresponds to the same visual direction in space. if a patient develops strabismus, the fovea of one eye will be deviated compared to the fellow eye, resulting in diplopia and condition

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25
ARC and ET
nasal non foveal point
26
ARC and XT
temporal non foveal point
27
angle of anomaly
distance between the "new fovea" and the actual fovea difference between the objective angle of deviation (the deviation measured by CT) and the subjective angle of deviation (the patient's perception of the magnitude of the deviation)
28
harmonious ARC
present when the angle of anomaly equals the objective angle of deviation. In other words, the new foveal point of the deviated eye corresponds with the fovea of the fellow eye so that the subjective angle of deviation is zero. The patient WILL NOT have symptoms of diplopia or confusion. This is the most common type of ARC -the Fn of the deviated eye is constantly changing, depending on where the patient is looking., At any point in time, the point on the retina that is hit by the object in the deviated eye will become the Fn and will be linked to the f of the fellow eye under binocular conditions
29
UHARC
present when the angle of anomaly is less than the objective angle of deviation. in other words, a point in between f and fn (where the object hits the retina) in the deviated eye becomes linked to f in the fellow eye. the subjective angle DOES NOT equal zero, and the patient WILL have diplopia and confusion (although less than with NRC) because there is not perfect correspondence between the two eyes CT=10BI Maddox=5BI
30
type 1 paradoxical ARC
occurs when the point used to fixate the object in the deviated eye is further away from the fovea than fn (whereto object hits the retina). In other words, the subjective angle of deviation is greater than the objective angle of deviation. Both the subjective and objective angles of deviation are in the same direction (both esophaguses or both exo) CT=10BO Maddox=5BO
31
type 2 paradoxical ARC
occurs when fn moves in the direction OPPOSITE to the deviation, causing the subjective and objective angles of deviation to be in opposite directions. Patients will have worse diplopia and confusion than if they had NRC
32
paradoxical ARC in ET
when fn is TEMPORAL to f in the deviated eye
33
paradoxical ARC in XT
when fn is NASAL to f in the deviated eye
34
harmonious ARC
angle of anomaly=objective angle and deviation-no diplopia
35
unharmonious ARC
angle of anomaly < objective angle of deviation-diplopia is present but less than with NRC
36
type 1 paradoxical ARC
angle of anomaly objective angle-greater diplopia than with NRC
37
type 2 paradoxical ARC
angle of anomaly>objective angle of deviation-greater diplopia than with NRC
38
after image test
detects ARC. A line light image is flashed before each eye separately, with one eye receiving a horizontal image and the fellow eye receiving a vertical image. If the patient has NRC, the patient will see a plus sign (regardless of whether there is a deviation present). If the two lines are shifted horizontally, the patient has ARC
39
horror fusionis
patients who have a tropia and cannot obtain fusion with prism correction. The patient will report the images become closer together with the addition of prism, but the images will eventually jump over each other without fusion
40
what tests can detect suppression
W4D, 4BO, and Bagolini lenses
41
bagolini lenses
good for ARC and suppression. they are Plano, clear, striated lenses that produce a line image 90 degrees from the orientation of the striations when the patient views a light source (similar to Maddox rod). The lenses are oriented so the right eye sees a line oriented as / (striations at 45 degrees) and the left eye sees a \ (striations at 135 degrees)
42
most sensitive test for retinal correspondence
bagolini lenses
43
bagolini: /
OS suppression
44
bagolini: \
OD suppression
45
Bagolini: X
NRC if cover test shows no tropia | HARC if cover test shows tropia
46
bagolini: V
ET with NRC or UHARC
47
bagolini: ^
XT with NRC or UHARC
48
4BO test
detects a small suppression scotoma in a patient with a microstrabismus (less than 10) that cannot be detected on CT (the patient will likely have a mildly reduced VA without an apparent ocular etiology). As the patient views a distant target, a loose 4BO prism is introduced in front of one eye and the clinician observes the movement of both eyes.
49
normal 4BO test
OS makes an outward moment and then re-fixates on the target
50
4BO OS suppression
OD moves in and OS moves out due to Herings law. However, OS will not move back in
51
4BO OD suppression
left eye never moves
52
zero degree fusion
no fusion, monocular/supression
53
first degree fusion
superimposition targets. testing uses two very different targets, patients will have diplopia as the targets are difficult to suppress used in anti-suppression therapy
54
second degree fusion
flat fusion testing uses identical targets with suppression checks. patients do NOT have diplopia. The image is single but is NOT in stereo. Requires motor fusion
55
Third Degree fusion
ultimate sensory fusion characterized by stereopsis. Requires motor and sensory fusion
56
visuoscopy
detects EF, which occurs when a patient uses a non-foveal point to fixate on object in the deviated eye under monocular conditions. The patient is asked to look in the center of a grid target in the direct ophthalmoscope under monocular conditions. The examiner views the location if the foveal light reflex in relation to the center of the grid
57
visuoscopy: FLR centered
no EF
58
visuoscopy: grid superior to FLR
superior EF
59
visuoscopy: grid inferior to FLR
inferior EF
60
visuoscopy: grid temporal to FLR
T EF
61
visuoscopy: grid nasal to FLR
F EF
62
tests for EF
VHS - visuoscopy - haidengers brushes - MAxwells spot - Monocular Hirschberg
63
Bruckner
used to detect strabismus, anisometropia, and/ormedia opacities in infants. The examiner uses a direct Oscope 80-100cm away from the patient on the midline to view the red reflexes of the two eyes as the patient views the lights, the Brightness of the red reflexes are compared to each other
64
deviated eye on bruckner
brighter
65
darker eye on Bruckner
SOS - smaller refractive error eye - opacity - straight eye
66
when should infantile ET be treated
should be corrected with surgery prior to 2 years of age in order to increase the likelihood of BV and stereopsis following correction of the deviation
67
treatment guidelines for strabismus
``` optical correction plus or minus lenses VT prism patching or atropine EOM surgery ```