4 - Amblyopia

Question 1

Amblyopia

• aka
• occurs when
• causes

Answer 1

Functional amblyopia, lazy eye

The visual pathway failed to develop properly due to inadequate stimulation (pathway halted during visual immaturity)

Form deprivation and/or abnormal binocular interaction

Question 2

Amblyopia

• corrective lenses
• pathology
• frequency (% population)

Answer 2

Cannot improve

Absent

2-4%

Question 3

Amblyopia

• most common cause of __
• laterality
• suspicious VA findings

Answer 3

Monocular visual impairment in children & mid-age adults

Uni or bi

Loss of at least 2 lines

Question 4

Critical period

• age
• abnormal input after CP
• effect of amblyogenic factors
• can you tx too early, late

Answer 4

Up to 8-10 yo

Blur (-) halt to sensory development

Different factors may affect differently (e.g. aniso vs isometropia)

Yes - too early may affect emmetropization, too late may lead to amblyopia

Question 5

Risk factors for amblyopia

Answer 5

Prematurity
Low birth weight
ROP
Cerebral palsy
Mental retardation
Genetic syndromes
Family hx
Maternal smoking, alcohol, drugs

Question 6

Amblyogenic conditions: refractive

• cause
• examples

Answer 6

Blur

Anisometropia
Isoametropia
Meridonal

Question 7

Amblyogenic conditions: form deprivation

• cause
• examples

Answer 7

Degraded image or occlusion

Cataract
Ptosis
Corneal opacity
Post seg hem (e.g. shaken baby)
Prolonged penalization/occlusion

Question 8

Amblyogenic conditions: strabismus

• cause
• examples

Answer 8

Different targets/no bifoveal fixation

ET
XT
Hypertropia

Question 9

Isoametropic amblyopia

• describe
• hyperopia

Answer 9

Very high refractive error OU

High hyperopia may cause an ET - may not if child is not in school/has no need to accomm -> didn’t develop a strab

Question 10

Anisometropic amblyopia

• describe
• common complaints

Answer 10

Normal refractive error one eye, other significant refractive error & reduced acuity

“That’s my bad eye”
“My left eye never sees well”

Question 11

Hyperopic anisometropic amblyopia

• as little as __
• if both eyes are hyperopic, __
• __ can be affected
• W4D

Answer 11

1D

Less hyperopic can maintain control, keep some motor & sensory fusion

Stereo

Can show fusion, may also pick up a central scotoma

Question 12

Myopic anisometropia

-moderate

Answer 12

Less than 5D

Can be “good” for you - one eye sees D, other N

Amblyopia unlikely to develop bc each eye attains clarity at a certain distance

• 0.75 OD (sees D)
• 3.25 OS (sees N)

Question 13

Meridonial amblyopia

-describe

Answer 13

Uncorrected high astigmatism in one/both eyes

Question 14

Amblyogenic refractive errors:
Isoametropia
-hyperopia
-myopia
-astigmatism

Answer 14

H: 5.00 or more D

M: 6.00 or more D

A: 2.50 or more D

Question 15

Amblyogenic refractive errors:
Anisometropia
-hyperopia
-myopia
-astigmatism (meridonial)

Answer 15

H: 1.00 or more D

M: 3.00 or more D

A: 1.50 or more D

Question 16

Form deprivation

-describe

Answer 16

Obstruction of the line of sight that prevents a clear image to form on the retina

Question 17

Strabismic amblyopia

• more likely to develop
• less likely to develop

Answer 17

Unilateral

Intermittent or alternating (even constant)

Question 18

Strabismic amblyopia

-the later the onset of strab, __

Answer 18

The better chance of re-establishing fusion that the pt has already developed

Question 19

Hysterical amblyopia

• cause
• who
• next steps

Answer 19

Psychological - anxiety, stress

Girls 8-14 yo

Add’l testing: VF, neurological, electrophysiology

Question 20

Organic amblyopia

• cause
• presentation
• management

Answer 20

Toxic or nutritional

Reduced VA, absolute scotoma, progressive vision loss, optic nerve atrophy

May be reversible, may need low vision aids for profound loss

Question 21

Tips for handling malingerers

Answer 21

Start VAs at 20/10
Use plano lenses in phoroptor
OKN drum (VAs at least 20/200 if they follow grating)
Electrophysiology
Clover pattern VF
Thorough hx
When in doubt, cyclo

Question 22

Studies: patching vs atropine

Answer 22

Both well tolerated

More pts in atropine group had reduced VAs at 6 mo, but did not persist

Both have similar improvement & are appropriate for initial tx of moderate amblyopia children 3-7 yo

Question 23

Studies: patching vs atropine follow-up

Answer 23

After initial 6 mo, there was no significant difference b/w atropine or patching groups up to 2 years

Question 24

Studies: full-time vs part-time patching

Answer 24

6 hours of daily patching = full-time patching in tx severe amblyopia in children 3-7 yo

Question 25

Studies: patching 2 hrs vs 6 hrs

Answer 25

2 and 6 hours of daily patching have similar VA improvement in tx moderate amblyopia in 3-7 yo

Question 26

Studies: amblyopia tx in children 7-17 yo

Answer 26

Optical correction worked ~25% for both 7-12 yo and 13-17 yo

Treatment worked ~50% for younger, ~25% for older kids

***responded better if they had not been tx before (patching or atropine)
I.e. tx may be of limited benefit if amblyopia was previously tx with patching

Question 27

Studies: atropine daily vs weekends

Answer 27

Both have ~same magnitude of improvement in children <7 yo (just do weekends)