Amblyopia Flashcards
1
Q
Amblyopia
A
Sensorimotor adaptations for abnormal BV
2
Q
Decrease of VA in one or both eyes caused by abnormal binocular interaction or form deprivation
A
Amblyopia (aka functional amblyopia, lazy eye)
3
Q
Amblyopia occurs when
A
The visua lapthway failed to develop properly due to inadequate stimulation
Pathway development was halted during visual immaturity
4
Q
Imropvement of amblyopia with corrective lenses
A
Cannot be improved
5
Q
Pathology and amblyopia
A
Absent
6
Q
If amblyopia not treated
A
Persists throughout life
7
Q
Most common cause of monocular visual improvement in children and middle aged adutls
A
Amblyopia
8
Q
Decrease of VA is caused by ___ in amblyopia
A
From deprivation and/or abnormal binocular interaction
9
Q
In addition to the loss of VA, amblyopia can result in
A
- dysfunction of accommodation
- poor eye alignment
- reduced contrast sensitivity
- dysfunction in spatial judgements
- poor resolution
- poor tracking
- poor prognosis with the loss of the fellow eye
10
Q
Prevalence of amblyopia
A
- about 2% in Caucasian and AA preschool children (Baltimore PED eye study)
- 2% of Hispanic and AA preschool children (multi ethnic PED eye disease)
- consistent with established estimates of 2-4% in the US population
11
Q
Cause or etiology of amblyopia
A
None that can be treated or reversed. None can be detected by physical examination of the eye
-implying that no diseases are seen
There is also poorer prognosis if there is loss to the sound eye
12
Q
Laterality of amblyopia
A
Unilateral or bilateral
13
Q
Severity of amblyopia
A
Can be mild or severe VA loss
14
Q
When to be suspicious of amblyopia
A
If there is a loss of at least two lines of VA that is not caused by a-ethology or correctable by ordinary refractive correction
15
Q
When should amblyopia be detected
A
Before the end of the critical period (8-10 years)
16
Q
Critical period
A
During this critical period, the visual system is still developing; thereby, stimulation helps with the development of the visual system
-treatment will be better during this period
Abnormal input or a lack of input results in a blurred image
-this will persist if not treated
17
Q
Abnormal input after normal critical period
A
Results in blur but not a halt to the sensory development of the VA
18
Q
How could critical period be affected differently
A
By amblyogenic factors such as anisometropia vs isometropia
19
Q
Treating refractive errors in young kids
A
There is a need for emmetropiation, where treating early could upset the natural change needed in these infants
But treating too late could also lead to amblyopia
20
Q
Risk factors of amblyopia
A
Prematurity Low birth wt ROP Cerebral palsy Mental retardation Genetic syndromes Family Hx Maternal smoking, alcohol, and/or drugs
21
Q
Causes of refractive amblyopia
A
Blur
22
Q
Cause of deprivation amblyopia
A
Degraded image or occlusion
23
Q
Cause of strabismic amblyopia
A
Different targets (no bifoveal fixation)
24
Q
Examples of refractive blur
A
Anisometropia
Isoametropia
Meridonial
25
Examples of deprivation amblyopia
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Cataract
Ptosis
Corneal opacity
Posterior segment hemorrhage
Prolonged penalization/occlusion
```
26
Strabismic amblyopia examples
Esotropia
Exo tropia
Hypertropia
Greater risk if constant
27
Isomatropic amblyopia
Caused by very high refractive error in both eyes
So high that a clear retinal image cannot be obtained
This results in a bialteral decreases in VA
28
High hyperopia can also cause an
Esotropia, but not always
Example is a 4 yo and hasn’t started school ye. No motivation to learn to accomodation
We have to count on the parents vigilance at this point
29
Anisometropia amblyopia
- a child has normal refractive error with good VA in one eye and a significant refractive error and reduced VA in the other eye
- binocualr integration is disrupted
- commons comments from children: “my left eye never sees well”, “that’s my bad eye”
30
Parents detecting anisometropia amblyopia
Harder because the child relies heavily on the better seeing eye
A child could be missed if the eye dr does not do entrance tests properly
- VA with both eyes open
- not making sure each eye is properly to prevent peeking
- skipping parts of the exam
- assumptions that little children cant have visual impairments
31
Anisometropia amblyopia and uncorrected refractive error
Causes a constant blur that prevents the brain from getting clear information via the visual pathway
The effect of blur is highest in the critical period of development of the visual system (in the first years of life)
32
Hyperopic anisometropia
Amblyopia resulting from a difference of hyperopia between the 2 eyes is common
As little as 1D of hyperopic anisometropia can affect
- proper fusion at D and N; and
- cause amblyopia in the more hyperopic eye
33
If both eyes are hyperopic
The less hyperopic eye can maintain control, keep some motor and sensory fusion
In some cases, eso could develop
34
In hyperopic anisometropia, what can be affected
Stereo
W4D could sho fusion depending on the severity of the amblyopia
You could also pick up a scotoma
35
Myopia anisometropia
High unilateral myopia with lesser myopia in the other eye
36
Will this person get amblyopia
OD: -0.75D
OS: -3.25D
Not likely. In this case because both eyes attain clarity at either distance or near
OD used for distance
OS used for near
37
Meridonial amblyopia
- caused by uncorrected high astigmatism in one or both eyes
- this amblyopia can easily be missed due to the orientation of the astigmatism, eg. some children may be able to squint or compensate
38
Amblyogenic risk factors: isoametropia astigmatism
>2.50D
39
Amblyogenic risk factors: isoametropia hyperopia
>5D
40
Amblyogenic risk factors: isoametropia myopia
>6D
41
Amblyogenic risk factors: anisometropic hyperopia
>1D
42
Amblyogenic risk factors: anisometropic myopia
>3D
43
Amblyogenic risk factors: anisometropic astigmatism
>1,50D
44
Form deprivation
- obstruction of the line of sight that prevents a clear image toform on the retina
- it can occur in one or both eyes
45
Physical obstructions that can lead to amblyopia include (not limited to)
```
Congenital cataracts
Ptosis
Traumatic opacity
Vitreous opacity
Vitreous hemorrhage (shaken baby syndrome)
```
46
Strabismic amblyopia
- a unilateral strabismus is more likely to cause amblyopia
- an intermittent strabismus or an alternating (even constant) is less likely to lead to amblyopia
- with the absence of bifoveal fixation, there is confusion and diplopia
- the visual system inhibits this by suppressing the image from the turn eye
- due to this inhibition and suppression, there are cortical changes
- EF develops because a non fovea point is used
47
Strabismic amblyopia and the later onset
The later hte osnet of strabismus, the better the chance of reestablishing fusion that the patient already developed
If someone has good fusion before it happened, there is a very small chance its amblyopia. Esp if they are 70
48
Hysterical amblyopia
- psychological origin
- anxiety
- reduced VA OU
- no significant refractive error
- no strab
- no ocular pathology
49
Notes about hysterical amblyopia
-common in girls 8-14
-blurred VA complaints
0additiona testing, such as VF, merit testing and electrophysiology needed to rule out other problems
-parent education and the need for referral for psychological help
50
Organic amblyopia cause
Toxic or nutritional
- reduced VA OU
- absolute scotoma present
- history of an exposure or deficiency
51
Notes on organic amblyopia
- this can be seen in undernutrition or deficiency
- progressive VA loss
- may or may not be reversible
- optive nerve atrophy is common
- may need low vision for profound VA loss
52
Intentionally providing wrong respsones for gain
Malingerers
-try to out play the dr
0they dont want to cooperate
-likely an absence of amblyogenic factors
Beware of them that actually have problems
Be patient
Communicate it’s pateint to determine the cause
53
Tips for malingerers
Start the VA chart from 20/10
Use Plano lenses to get VAs
Use the OKN drum (va at least 20/200)
Electrophysiology
Clover leaf pattern on VF
Thorough history to r/o any true problems that cause decreased vision
When I n doubt because of inconsistent results, always cycloplege the patient
54
Amblyopia treatment studies
-PED eye disease investigator Gouda (PEDIG) is a collaborative network that facilitates multicenter clinical research in strab, amblyopia and other eye disorders that affect children
Funded by NEI
USA, UK, and Canada
Helps with how we treat amblyopia today
55
Level of evidence in research h
Pyramid starting at the bottom
- editorials, expert opinion
- case series, case reports
- case-control studies
- cohort studies
- randomized controlled trials
- systematic reviews
56
Randomized controlled trials
-scientifically sound
57
Systematic reviews
Sound research papers and integrates everything and synthesize a finding
58
Objective of ATS 1
RCT comparing patching and atropine for moderate amblyopia (20/40 to 20/100) in children less than 7 years
59
Outcome of pathing vs atropine
VA in the amblyopic and sound eye after 6 months
60
Conclusion of patching vs atropine
Atropine and patching have similar improvement, and both are appropriate for initial treatment of moderate amblyopia in children aged 3 to less than 7 years
61
Results of pathing vs atropine
Patching slightly better than atropine but both close
62
Notes about atropine and patching
Both treatments were well tolerated
-more pateitns in the atropine group had reduced acuity in the second eye at 6 months, but this did not persist with further follow up
63
Objective of patching vs atropine F/U
To compare patching and atropine for moderate amblyopia (20/40 to 20/100) in children less than seven 18 months after completion the ATS 1
64
Treatement in patching vs atrophied F/U
FU for patching or atropine done for 6 months to observe effects of treatment, further treatment, better 6months and 2 years, was at the discretion of the investigator
65
Outcome of the patching vs atropine FU
VA in the amblyopic eye and sound eye after 2 years
66
Results of the patching vs atropine FU
Average improvement from baseline in both groups, patching slightly better
67
Conclusion on patching vs atropine FU
After the initial 6 month treatment, there was no significant difference between the atropine or patching when followed by best clinical care until 2 years
68
How long should we patch or atropine for
Probably at least 2 years because there was the greates improvement
69
Objective of full time vs part time patching
RCT tocompare full time patching (all hours or all by 1 hour per day) to 6 hours of family patching for severe amblyopia (20/100 to 20/400) in children less than 7
70
Treatment of full time vs part time patching
Full time patching or 6 hours of patching per day, each combined with at least 1 hour of near VA when patching
71
Outcome of full time vs part time patching
VA in the amblyopic eye after 4 months
72
Results of full time vs part time patching
6 hour patching group had the same effect as full time patching, no point in full time patching
A lot of improvement in 4 months
73
When do we want to see a patching patient back
4 months
74
Notes of full time vs part time patching
VA in the ambl;yiov eye improved similar amount in both groups
75
Conclusion of full time vs part time patching
6 hours daily patching and full time patching produce similar improvement in treating severe amblyopia in children 3 to less than 7 years of age
76
Patching 2 vs 6 hours results
Average improvement in VA in the amblyopic eye from baseline was the same in both group
77
Conclusion of 2 vs 6 hours patching
Similar VA improvement
78
Objective of amblyopia treatment in kids 7-17
RCT to evaluate the effectiveness amblyopia treatment (20/40 to 20/0400) in kids 7-17
79
Outcome of amblyopia treatmetni nchildren aged 7-17
Children with VA improvement 10 or more letters by 24 weeks
80
Results of ambl;tapia treatment in kids 7-17
In 7-12 years old
- VA improvement in optical correction group: 25%
- VA improvement in treatment group: 53%
In 13-17
- VA improvement in optical correction group: 23%
- VA improvement in treatment group: 25%
But more responders in the treatment group and 20% in the optical correction group IF THEY HAD NEVER BEEN TREATED WITH PATHCING AND/OR ATROPINE BEFORE
81
The older kids that did well with pathcing and atropine
They do better if they have never been treated with patching and/or amblyopia before
82
Conclusion of amblyopia 7-17
- amblyopia improves with optical correction alone in about 1/4 of patients aged 7-17, but most required additional treatment for amblyopia because of residual deficits in VA
- 13-27: 2-6 hours of pathcing daily works well is not been previously treated at all
83
Daily vs weekend atropine: objective
Comparing daily atropine toweekend atropine for the treatment of moderate amblyopia in children younger than 7
84
Results of atropine daily vs weekend
At least 20/25 or VA equal to better eye seen in
- daily atropine group: 47%
- weekend atropine: 53%
Stereopsis was their same
85
Conclusion of atropine daily vs weekend
Same magnitude
Just give it to them on the weekend
