Strabismus In NM Abnormalities Flashcards
(137 cards)
1
Q
Infancy ocular instability (split)
A
Normal
Variable, transient, intermittent angle strabismus
-seen in 2-3 months
-resolves by 4 months
-suspect problem if deviation persists, is constant and/or larger
2
Q
Esodeviation
A
Could be a tropia or a phoria
3
Q
A latent esodeviation controlled by fusional vergences so eyes are aligned in binocular conditions/fusion
A
Eso phoria
4
Q
Manifest deviation not properly controlled by fusional vergences
A
Eso tropia
5
Q
Deviations can come from
A
NM abnormalities can be due to innervation, anatomical, mechanical, refractive, accommodative or genetic problems
6
Q
Fusional vergences allow
A
Fusion and alignment
7
Q
Appearance of ET when eyes are actually straight
A
Pseudoesotropia
8
Q
Pseudoesotropia
A
Hirschberg and CT will be normal
- seen in children with wide, flat nose bridge with prominent epicanthal folds and small interpupillary distance
- pinch the most bridge
- appearance approves with age
- these children may actually have a deviation
9
Q
Onset is between birth and 6 months, has a larger constant esotropia, there may be a family Hx of ET
A
Infantile (congenital) ET Usually LARGE (60 prism D)
10
Q
Many children with infantile ET have
A
Other Neuro or developmental condition, cerebral palsy, hydrocephalus, prematurity
-many have cross fixation, using the addicted eye to look into the contralateral view
11
Q
Many kids with this use cross fixation
A
Infantile congenital ET
-using the addicted eye to look into the contralateral view
12
Q
Amblyopia and infantile ET
A
Amblyopia may develop in the constantly deviated eye (even with cross fixation)
13
Q
This has a HUGE deviation
A
Infantile ET
14
Q
Why kind of refractive error is associated with infantile ET
A
Hyperopia
15
Q
What test do you do to see how the eyes are moving in infantile ET
A
Dolls head
-see the eyes to see abduction (appears difficult because of cross fixation)
16
Q
Pathogenisis of infantile ET
A
Could be sensory or motor
17
Q
Other variable findings in infantile esotropia
A
Amblyopia A or V pattern Dissociated vertical deviation (DVD) OIO (overaction of IO) Nystagmus AHP
About 30-50% of all esotropes
18
Q
This makes up about all 30-50% of all kids with esotropia
A
Infantile ET
19
Q
Management considerations in strabismus
A
- correction of refractive error
- added lenses (bifocal, plus, minus)
- prism
- occlusion
- VT
- pharmacological (Botox)
- surgery (esp for large angles)
20
Q
Infantile ET management
A
Comprehensive eval
Full cyclo refraction
Ask mother about pregnancy
Surgery allows some degree of fusion after surgery
21
Q
Purpose of full cyclo refraction in infantile eso
A
This is to rule out early onset accommodative ET. Smaller, variable intermittent ET angles are likely to respond
22
Q
Deviation in accommodative esotropia
A
Associated with the accommodative reflex
23
Q
When does accommodative eso tropia occur
A
Between 6 months and 7 years (average age of onset is 2.5 years)
24
Q
How does accommodative ET start
A
Intermittently and then may become constant, often hereditary , trauma can precipitate it
25
Amblyopia and diplopia and accommodative ET
Often present with large constant and unilateral angles, diplopia may result, but then there is active suppression
26
Refractive accommodative ET
Due to high hyperopia
27
Non refractive accommodative ET
Due to high AC/A
28
Mixed accommodative ET
Due to high hyperopia and high AC/A
29
About 50% of all ET have a _______ component
Accommodative
30
Due to uncorrected hyperopia and insufficient fusional vergence and diverge
Refractive accommodative ET
31
Uncorrected hyperopia causing refracting accommodative ET
Forces the patient to accomodate to sharpen retinal images, this leads to accommodative convergence
-ET develops if patient doesn't have enough fusional divergence to counter the increases concvergence
32
Size of ET in refractive accommodative ET
20-20PD
| Could be intermittent, alternating with asthenopia
33
Deviation at distance and near for refractive accommodative ET
Similar deviation at d and n
34
Average hyperopia that can cause refractive accommodative AT
+4D
| Can be as little as +3 and as much as +6
35
If hyperopia is >6D in refractive accommodative ET
Isometropic amblyopia develops because patient has too much blur and will be unable to try to accommodate
36
Management of refractive accommodative ET
- comprehensive eval
- cyclo refraction: get out all the plus you possibly can. Offer full hyperopia correction for full time wear ASAP, if not some of the esodeviation will not longer respond to hyperopia correction
- can reduce plus later to aid emmetropization
- start amblyopia tx if VA doesn't fully improve with Rx
37
Due to a high AC/A ratio
Non refractive accommodative ET
38
What causes a non refractive accommodative ET
An increase in accommodation at near drives convergence, but there is insufficient vergence to diverge
39
When is ET greater in non refractive accommodative ET
Greater at near because of the need for accommodation at near, always important to eval angle at distance and near, may be intermittent and alternating angle
40
What kind of refractive error is ssen with non refractive accommodative ET
Moderate hyperopia to myopia is seen, similar to general population
41
Amount of convergence induced by a change in accommodation
AC/A
42
A change in accommodation is accompanied by a change in
Vergence
43
What permits clear stable single binocular vision across range of viewing distances
Accommodation and vergences
44
What helps evaluation the strength between the accommodative and vergences systems
AC/A
45
Where are abnormal AC/A ratios seen
In binocular problems
46
Calculating AC/A ratio,
Look at the notes
47
Management of non refractive accommodative ET
- Treat underlying refractive error
- bifocals reduce accommodation and thereby accommodative convergence (Rx based on AC/A ratio)
- seg height must bisect the pupil
- repeat cyclo yearly
- surgery contraindicated
48
Why is surgery contraindicated in no refractive accommodative ET
May be weaned off add if there is improved alignment at near (start about 7 years)
49
Why do we want to bisect the pupil with the bifocal in kids with non refractive accommodative ET
To force them to look through the bifocal. Kids will try to look over the top of it
50
Combination of refractive acocmmodation and non refractive accommodative findings, high hyperopia and high AC/A
Mixed accommodative esotropia
51
Management of mixed accommodative ET
Full hyperopia correction of kid
Bifocal based on AC/A
Surgery contraindicated (unless residual larger angle bc glasses started too late)
52
Where will the ET be for a mixed accommodative ET
Distance and near!
53
Accommodation contributes to, but does not account for the entire deviation
Partial accommodative ET
54
There is a reduction in the angle, but there is residual ET after treatment. This may result after delayed treatment of truly accommodative ET
Partial accommodative ET
55
What is the ET in partially accommodative ET
Constant, unilateral, suppression, ARC common
56
Early onset non accommodative esotropia and acute acquired ET
Non accommodative ET (basic ET), acocmmodation not driving here
57
Early onset nonaccommodative ET onset
After 6 months of age to before age 2
| -clinically similar to infantile ET, but the onset is later.
58
ET in early onset non accommodative ET
ET same at distance and near, commitment
59
Accommodative and refractive component to early onset non accommodative ET
No acommodation invovled
| Insignificant amount of hyperopia
60
Management of early onset of non accommodative ET
- correct refractive error, consider prisms or bifocal
- amblyopia tx
- VT to improve ranges
- consider surgery
- consider Neuro cases (even if child appears healthy)
61
What kind of ET in acute acquired ET
Comitancy, unilateral and constant moderate angle (20-30pd)
62
Onset of acute acquired ET
Sudden onset from 3-5 yo (or older)
63
Refractive error in acute acquired ET
Refractive error similar to general population
64
What could be the result of acute acquired ET
Illness, stress, aging
65
Management of acute acquires ET
- neuro eval asap
- correction
- prism or surgery since pt probably had BV before the ET
- amblyopia tx, if needed
66
Other esodeviations
```
Sensory ET
Divergence insufficiency ET
Micro tropia (ultra small ET)
Consecutive ET
Decompensating ET (fusional vergences no longer able to maintain EP)
```
67
An esotropia that develops due to vision loss in one eye
Sensory ET
68
Pathology of sensory ET
Pathology prevents clear, focused, retinal images. Prevents symmetrical visual stimulation OU
69
VA in sensory ET
Poor VA in affected eye
70
ET in sensory ET
Constant unilateral deviation and can be very large (10-45)
| -poor cosmetic
71
Decreased of vision loss in one eye can be die to any of the following
```
Congenital cataract
Corneal scarring
Optic atrophy
Prolonged blue
Retinal/macular disease
Anismetropia amblyopia
Ptrosis
PHPV
```
72
Management of sensory ET
- eliminate pathology as early as possible
- polycarbonate lens for full time wear (monocular precautions)
- treat secondary amblyopia
- surgery can be for any residual deviation (or basically for cosmesis)
73
A non accommodative esodeviation greater at distance then near
Divergence insufficiency ET
74
ET in divergence insufficiency ET
```
Comitancy
Onset in adults
Decreases fusional divergence at distance
Diplopia complains at distance
HA
```
75
Refractive error in divergence insufficiency ET
Refractive similar or normal population, no sensory adaptatios since late onset
76
Sensory adaptations in divergence insufficiency ET
None since late onset
77
Management of divergence insufficiency ET
- NEURO REFERRAL
- thorough eval (neuro concerns from head trauma, increased ICP)
- correct refractive error
- VT
- Botox
- sx not indicates since deviation only at distance
78
Esodeviation after exo strabismus surgery
Consecutive ET
79
Symptoms of consecutive ET
Patient could be symptomatic
Amblyopia could develop
Mag varies
Unilateral or alternating
80
Management of consecutive ET
- spontaneous improvement could occur
- treat refractive error
- try BO prism or plus lenses
- repeat surgery for large or symptomatic consecutive deviations
81
6h nerve palsy
Non comitant esodeviation, Duane's syndrome
82
A latent exodeviation controlled by fusional vergences
XP
83
Manifest deviation exodeviation
XT
84
Exodeviations are signs of
NM abnormalities that can result from innervation, anatomical, mechanical, refractive, accommodative or genetic problems
85
Prevalence of Xdeviation
Varies by ethnic groups
86
There is proper alignment, but positive angle kappa, wide pupil;Larry distance give appearance of Xdeviation
Pseudoesotropia
87
Latent deviation, controlled with fusional vergences
XP
88
If fusional vergevens are not adequate in XP
XT could result or XP becalmed symptomatic
89
Treatment for XP
Needed if there is asthenopia or diplop[ia
90
in childhood, XT larger at distance and seen prominently when target is at a distance
Intermittent XT: divergence excess type XT
91
In adults, XT same at distance and near in adults
Basic XT, intermittent XT
92
In adults, XT larger at near
Convergence insufficiency XT (intermittent XT)
93
Most common XT
Intermittent XT (85%)
94
Deviation is latent at times and then becomes manifest, onset before 5 (XT)
Intermittent XT
95
When does intermittent XT becalmed manifest
During visual inattention, fatigue, or stress because compensating fusional factors are not active
-could occur late int he day, with fatigue, when daydreaming, when drowsy.
96
Bright light in intermittent XT
Bright light may cause reflex closure of one eye
97
Can be asssociated with small hypersand/or A/V pattern
Intermittent XT
98
Untreated intermittent XT
Can led to constant XT it will start to manifest at lower levels of fatigue and occurs for longer
99
Sensory adaptations of intermittent XT
May occur after some diplopia, replaced with suppression or anomalies retinal correspondence in DE and Basic
- reduce stereo
- amblyopia possible
100
Eval of intermittent XT
- comprehensive Hx- age of onset, FREQUENCY or tropia, circumstances when it is manifested
- CT at d and n-IXT may be greater at distance because of some fusion at near keeping eyes straight
- controls assessment: good control (XT only on CT), fair control (XT on CT, fusion regained after blinking ore refixation), poor control (XT manifests spontaneously and for an extended period of time)
101
Eval of intermittent XT: sensory testing
In sensory testing, you could get good stero and normal retinal correspondence if control is good
102
Diplopia with good control in intermittent XT
Not common
103
Management of intermittent XT
- correct significant hyperopia, myopia, and astig
- mild myopia correction could make deviation better
- mild hyperopia correction could make deviation worse (so not typically Rx)
104
Mild hyperopia correction in intermittent XT
Could make the deviation worse
105
Moderate hyperopia in intermittent XT
Needs to be corrected bc a child may be unable to accommodate through this, resulting in blue and thereby a manifest XT
106
Minus lenses and intermittent XT
Can be added to correction to stimulate accommodation and stimulate accommodative convergence to control XT
107
Optical correction of intermittent XT
May actionalty make retinal image better and thereby improve XT
108
Patching for amblyopia in intermittent XT
Could improve control
109
VT inintermittent XT
Fusional vergence training, antisupression/diplopia awareness can be instituted with pathching, minus lenses, can be done before surgery
110
Prisms in intermittent XT
In the absence of suppression, can be used to promote fusion, but not long term because it reduced fusional vergence amplitueds
111
Surgery in intermittent XT
When XT gets progressively worse with decreasing stereoacuity and control. Deviation >50% of the time is concerning
112
Botox in intermittent XT
Can be used as well, but needs multiple treatments
113
XT greater at near than distance, usually an intermittent alternating deviation at near, low AC/A, poor near fusion convergence amplitudes and receded NPC
Convergence insufficiency XT
114
Symptoms of convergence insufficiency XT
Asthenopia, diplopia and blurred near vision- all common during reading
115
VT in convergence insufficiency XT
Successful in these cases- pencil push ups, convergence based computer programs
116
Convergence insufficiency XT prism
BI reading glasses could be used
117
Commonly seen in older patients with a sensory XT or patients with a longstanding XT that has decompensating (decompensating XP)
Constant XT
118
Surgery in constant XT
May be indicated
119
Large visual field in constant XT
Some patients like it
120
Examples of constant XT
Infantile XT
| Sensory XT
121
Large, constant angle (30-80PD), could alternate, XT
Infantile XT
122
Which is more common, infantile ET or XT
ET
123
When is infantile XT present
Before 6 months of age
124
What kind of problems likely in infantile XT
Neuro issues or craniofacial disorders
125
Adduction on versions in infantile XT
Poor, full on ductions
126
DVD and OIO in infantile XT
Common
127
What kind of Hx needed for infantile XT
Good developmental Hx is needed and consider neuro consult
128
Management of infantile XT
Treat refractive error
| Treat amblyopia
129
Surgery for infantile XT
Performed for these children, early to promote some form of sensory cooperation, since prognosis for BV is poor (even if it is a monofixation or micro tropia)
130
Any condition that causes vision loss in one eye can lead to sensory XT
Sensory XT
131
Why do some people have sensory XT vs ET
Not sure
132
Symptoms of sensory XT
Poor VA
Poor cosmesis
Constant and unilateral
Larger angle
133
Management of sensory XT
Need to determine if VA can be improved since this may improve alignment with peripheral fusion
134
If VA can be improved in sensory XT
Surgery can be useful for better alignment
135
If VA cannot be improved for sensory XT
Misalignment could occur again after surgical correction
136
This is common post surgery- could occur after months or years of surgery
Consecutive XT
137
Consecutive XT before another surgery
Need to consider type and amount of previous surgery, any duction limitation/scarring or on comitancy
