Clinical: Smooth Vergences Flashcards
1
Q
Bifoveal fixation is
A
retinal images aligned and on the fovea of both eyes
2
Q
when a patient does not have corresponding retinal points they may experience
A
double vision
3
Q
What stimulates motor fusion for vergences
A
retinal disparity
4
Q
Motor fusion allows binocular vision and sensory fusion which creates
A
stereopsis
5
Q
Abnormal retinal disparity can occur due to:
A
- New onset eye turn
- prism induced in front of one eye
6
Q
Diplopia stimulates
A
vergence eye movements
7
Q
Vergence eye movements help re-establish _____, _____, and _____
A
fusion, binocularity, and stereopsis
8
Q
Versions are
A
conjugate eye movements
9
Q
examples of versions
A
saccades and pursuits
10
Q
Versions use ____ muscles
A
yoked
11
Q
vergences are
A
disconjugate eye movements
12
Q
What are three types of disconjugate eye movements
A
convergence, divergence, and vertical
13
Q
Four types of vergences:
A
Tonic convergence
fusional vergence
accommodative vergence
proximal convergence
14
Q
tonic convergence is
A
the difference between anatomic and physiologic positions of rest
15
Q
The anatomical position of rest for the eyes is described as
A
where the eyes would sit if there were no innervation for the EOMs and is based on anatomy of EOMs origins and shapes of orbit
16
Q
In anatomical position, the eyes would sit
A
in divergent position
17
Q
The physiological position of rest for the eyes is described as
A
constant, baseline innervational tine to the EOMs when awake/alert
18
Q
In physiological position, the eyes would sit
A
more convergent than anatomical position
19
Q
Tonic convergence determines the amount of _____ ____
A
distance phoria
20
Q
excess tonic convergence =
A
esophoria
21
Q
deficiency in tonic convergence =
A
exophoria
22
Q
Fusion vergence maintains
A
single, binocular vision
23
Q
fusion vergence compensates for
A
excess or deficient tonic convergence (a phoria)
24
Q
Fusion vergence prevents a phoria from becoming a
A
tropia
25
fusion vergence is autonomic but can be
voluntary
example: you can cross your eye
26
Positive fusional vergence(PFV) is
Eyes converge
27
Which patients use PFVs to maintain single vision? (eso or exo)
exophoria patients
28
Negative fusional vergence (NFV) is
eyes diverge
29
Which patients use NFVs to maintain single vision?
esophoria patients
30
Vertical Fusional vergence (VFV) is
eyes moving up or down
31
What do hypophoria pts use to maintain single vision?
supra vergence
32
what do hyperphoria pts use to maintain single vision?
infra vergence
33
Supravergnce moves eyes
UP
34
Infravergence moves eyes
DOWN
35
Accommodative vergence is
a change in convergence that occurs with a change in accommodation
36
excess plus lenses relax accommodation and cause the eyes to
diverge
37
excess minus lenses stimulate accommodation causing the eyes to
converge
38
Increasing the testing distance relaxes accommodation causing the eyes to
diverge
39
Decreasing testing distance stimulates accommodation causing the eyes to
converge
40
Negative Relative Accommodation(NRA) tests
relaxation of accommodation
41
NRA indirectly tests
PFVs
42
During the NRA test, you increase plus lenses so the the pt has to use
PFVs to keep the target single and clear
43
Positive Relative Accommodation(PRA) tests
relaxation of accommodation
44
PRA indirectly tests the
NFVs
45
During PRA, you increase minus lenses causing the pt to use
NFVs to keep the target clear and single
46
What vergence is used to calculate AC/A ratios
accommodative convergence
47
What is proximal convergence?
convergence due to awareness of a near target
48
What are the two methods of testing vergences:
1.smooth vergences
2.step vergences
49
During smooth vergences the pt will look at a single letter as the examiner increases the amount of prism forcing the eyes to
move the target to maintain single vision
50
During smooth vergences the target will move toward the
apex of the prism
51
During smooth vergences, as the target moves toward the apex of the prism it stimulates
retinal disparity so the eye must make vergence movment to keep binocularity
52
An object on the left visual field stimulates the temporal or nasal retina for OD and OS
OD: temporal retina
OS: nasal retina
53
During vergence testing, the prisms moves the image towards
its apex in the pts visual field
54
The image from the prism will project
to the retina of opposite visual field
55
The eye will turn in the direction fo the image in the visual field to
align fovea with retinal image and maintain binocular fusion
56
A BI prism over the left eye moves the image
out of the left visual field
57
A BI prism over the left eye will move the target to project
to the left nasal retina
58
A BI prism over the left eye causes the eye to move ____ to maintain foveal fixation
out
59
Two types of lateral smooth vergence testing:
distance lateral vergences
near lateral vergences
60
What do you instruct the pt for distance or near lateral vergences?
inform me when the target becomes blurred and/or when the target becomes double
61
For distance and near lateral vergences you always test BI or BO first. Which one and why?
BI because BO affects accommodation and convergence that it may alter the BI results
62
Purpose of distance lateral vergence test
test the patient's ability to use horizontal vergence to maintain binocular vision
63
target for distance lateral vergence test
single letter, 2 lines larger than BCVA in the worse seeing eye
64
"0" for DLV is placed at
12 o'clock for both eyes
65
should you stop and write down each number the patient says blur or double at as you go through the test?
no just remember it and say it out loud idiot
66
To record DLV, you add
the prism from both eyes together as their total prism
for blur, break, recovery
67
The recovery prism should always be ___ than break
less
68
For base out vergences, when the image blurs, you've reached the pts ____ ___.
PFV limit OR accommodative limit?
69
For base out vergences, as you reach blur and keep going the pt is now using their
accommodative convergence- sacrificing clarity to avoid double vision
70
For base out vergences, when the image breaks the pt has reached their limit for ____ ___ AND ___ ____
fusional vergence and accommodative convergence
71
For base out vergences, when the image recovers it is back within the limit of the pts ___.
PFV
72
For base out vergences, If there is no blur reported then
the break is the limit of the pt's PFV
73
For base in vergences, when the image blurs, you've reached the pts ____ ___.
NFV limit OR accommodative limit?
74
For base in vergences, as you reach blur and keep going the pt is now
relaxing their accommodative convergence to diverge their eyes
75
For base in vergences, when the image breaks the pt has reached their limit for ____ ___ AND ___ ____
fusional vergence and accommodative convergence
76
For base in vergences, when the image recovers it is back within the limit of the pts...
NFV to allow fusion
77
For base in vergences, If there is no blur reported then
the break is the limit of the pt's NFV
78
When testing BI vergences at a distance there should be no ____ ___. Why?
blur point because your pt shouldn't be using accommodation at distance so there is nothing to relax
79
Near lateral vergences illumination
full overhead with stand lamp
80
Near lateral vergences has the near card at
40cm
81
target for near lateral vergences
a vertical line of letters
82
Two types of smooth vertical vergences testing
distance vertical vergences and near vertical vergences
83
You use vertical vergences when the pt has
hyperopia
84
should you have a blur point for vertical vergences
No, because accommodation is not used in vertical alignment
85
BU measures
infravergence
86
BD measures
supravergence
87
Purpose of distance vertical vergence test
test the patient's ability to use vertical vergence to maintain binocular vision
88
Target for distance vertical vergence test
single letter, 2 lines larger than BVCA in the worse-seeing eye
89
For DVV test, you place the "0" at
horizontal for both eyes
90
For vertical vergence test, you only move
the prism over ONE eyes, not both
91
For recording vertical vergences make sure to include
distance or near
which eye was tested
92
If you go past zero for recovery, you record it as
a negative number
93
vertical phorias are defined by the
hyper eye
94
For DVV, when the image breaks, you have reached the pt's limit for
supra/infra vergence
95
For DVV, when the image recovers you are back within the
patients' vertical vergence and they are able to regain fusion
96
illumination for near vertical vergence
full overhead with stand lamp
97
target for NVV
horizontal line of letters, near card at 40cm
98
Vergence testing with BI/BO measures
reserves or magnitude of fusional vergences
99
pts with large, long-standing phorias may have
large compensating vergences
100
Pts with large compensating vergences have binocular systems that have
adapted which keeps them asymptomatic
101
if a patient with a longstanding 15 exophoria has a large amount of PFV, their
BO blur value will be high
102
If there is not enough compensating vergence, it will not be sufficient to compensate for a phoria and it will lead to
a patient being symptomatic
