Term
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Definition
+/- 2.00 D
monoc = >11cpm
binoc = > 8 cpm |
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Term
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Definition
12PD BO and 3PD BI:
> 15cpm
Best target = single vertical line of letters |
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Term
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Definition
2x flipper value
monoc > 22cpm
binoc > 16 cpm |
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Term
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Definition
| 1 prism diopter is = displacement of 1 cm at a viewing distance of 1 meter |
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Term
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Definition
Maddox classification:
The sum of Tonic, Proximal, Accommodative, and Disparity Vergence |
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Term
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Definition
w.d. = 40 cm
look for symmetrical reflex
each 1 mm of reflex displacement = 22 PD or 11 degrees of deviation |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
Break: 3-4
Recovery: 1.5-2 |
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Term
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Definition
marked limitation of abduction (mimiking CN VI paresis)
notable difference: retraction of globe and narrowing of palpebral fissure |
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Term
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Definition
usually congenital, anomaly w/ superior oblique tendon/trochlear complex
absence of elevation in adduction of affected eye --> stimulates paresis of inf oblique |
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Term
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Definition
1. primary muscle restriction
2. overaction of the contralateral synergist
3. contracture of the direct antagonist
4. secondary inhibitional palsy of the contralateral antagonist |
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Term
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Definition
| contraction of a muscle is accompanied by the simultaneous and proportional relaxation of its antagonist |
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Term
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Definition
| contralateral synergists are equally innervated when a movement is executed by both eyes |
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Term
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Definition
| Binocular perception of depth based upon retinal disparity |
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Term
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Definition
images on non corresponding retinal points but still seen as single
typically around 6-10 mins of arc at the fovea
30-40 mins @ 12 degrees away |
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Term
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Definition
| smallest distance between two objects where the observer can judge that one is behind the other |
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Term
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Definition
threshold detection of binocular disparity
smallest difference in retinal disparity that is perceived in depth (beta - alpha) |
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Term
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Definition
Pro = 2 seconds of arc
Average = 20 seconds of arc (stdev = +/- 10 sec)
96% at least 40 seconds of arc |
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Term
| Ranges for polarized tests for stereo |
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Definition
Wirt circles = 400 -20 sec of arc
RDS = 400 - 250 sec of arc
both @ 40 cm |
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Term
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Definition
ACr/A is greater than ACs/A:
ACr/A = 1.08*ACs/A |
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Term
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Definition
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Term
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Definition
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Term
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Definition
image of a binoc fixated object does not fall on corresponding retinal points but are w/in Panums Fusional area --> seen as single
(microtropia) |
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Term
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Definition
| Prism necessary to eliminate the fixation disparity |
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Term
| Fixation disparity curves I, II, III, IV |
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Definition
I: normal
II: esophoric
III: exophoric
IV: most symptomatic pts
general rule: flat = good (except for IV) |
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Term
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Definition
Distance: 1XP, range 0-2 XP
Near: 3XP, range 0-6 XP
Dist BO range (positive): 9/19/10
Dist BI range (negative): X/7/4
Near BO (positive): 17/21/11
Near BI (negative): 13/21/13
Dynamic ret: +1.37
monoc x-cyl: +1.00
binoc x-cyl: +0.50
PRA/NRA: -2.37/+2.00
Gradient AC/A: 4/1 |
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Term
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Definition
best for XP
compensating range should be at least 2x phoria |
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Term
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Definition
zero demand point should lie in the middle third of the vergance range
best w/ EP |
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Term
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Definition
| for EP, add prism until phoria is equal to the BI recovery |
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Term
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Definition
if high AC/C, useful
must check the amplitude and the affects of the lenses on phoria and fixation disparity |
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Term
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Definition
fast fusional vergence stimulates slow fusional vergence which contributes to the total vergence response
output of slow fusional vergence --> increase accuracy of aggregate vergence response --> decline in fixation disparity |
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Term
| according to rosenfield, how much change in heterophoria is considered significant for extended dissociation? |
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Definition
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Term
| Which factor (blur, break, recovery) is most affected by prism adaptation? |
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Definition
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Term
| clinically, which method of FD quantification is commonly used? |
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Definition
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Term
| patients who show an absence of slow fusional vergence tend to have what presenting symptom? |
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Definition
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Term
| coefficient of prism adaptation (probably not important to memorize) |
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Definition
(B-A) - (C-A)
(B-A)
A = heterophoria immediately before prism
B = heterophoria immediately after intro of prism
C = heterophoria measured after 10 mins
No adaptation --> C = B so coefficent = 0
complete adaptation --> coefficient = 1 and C =A |
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Term
| Parameters of the blind spot (of Mariotte) |
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Definition
15 degrees from the optic nerve
7.5 degrees vertical and 5.5 degrees horizontal |
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Term
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Definition
| pts sees one object fine, but when a second is presented, one of the two disappears, maybe due to unilateral brain damage |
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Term
Visual field defect descriptions:
congruous, incongruous, altitudinal, homonymous, heteronymous, hemianopsia |
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Definition
congruous: defects are the same shape and size
incongruous: defects are different in shape and size
altitudinal: defects are either superior or inferior
homonymous: same half of both eyes
heteronymous: different half of both eyes
hemianopsia: affects one half of the visual field |
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Term
What are the defects:
prechiasmal, chiasmal, post chiasmal |
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Definition
prechiasmal: only in one eye
chiasmal: bitemporal
post chiasmal: homonymous (maybe congruous, incongruous, altitudinal) |
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Term
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Definition
each square measures 5 mm when held at 30 cm --> each square subtends 1 degree on retina
generally 10 degrees in all directions from center/fovea, if observed from corners --> 40 degrees around fovea? |
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