I am Optometrist Surendra Prasad sah

1. Amblyopia
Surendra sah
2nd
January, 2015
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Definition
 Amblyopia means “Dullness of vision”
(Ambly = dull + ops = vision)
 A condition of visual acuity not correctable
by refractive means and not attributable to
obvious structural and/or pathological
ocular anomalies

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 Visual Acuity
 Difference of 2 lines on a visual acuity
chart is commonly used as diagnostic
criteria for amblyopia
 OD: 20
/100
20
/30
 OS: 20
/20

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I am
suppressed

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Classifications
 Stimulus deprivation amblyopia
 Strabismic amblyopia
 Anisometric amblyopia
 Isometric amblyopia
 Occlusion amblyopia
 Secondary due to nystagmus
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Stimulus deprivation amblyopia
 Severe ptosis
 Corneal opacity
 Congenital Cataract
 Vitreous opacity
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Strabismic amblyopia
 Due to unilateral squint it develops as an
adaptation to avoid diplopia
 Most commonly seen in esotropia
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Clinical tests for Strabismic
amblyopia
 Fixation Preference
 Child strongly and repeatedly
objects to having the fixating eye
covered
 Free alteration safely assess that
amblyopia is absent

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Anisometric amblyopia
 Significant difference in
refractive error between
two eyes
 Hypermetropia is more
intense than myopia
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Isometric amblyopia
 Secondary to approximately equal high
refractive errors in both eyes
 Hypermetropia is more intense than myopia
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Occlusion amblyopia
 Prolonged occlusion therapy of
preferred eye
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Secondary to Nystagmus
 Latent or manifest nystagmus may decrease
vision
 In micronystagmus horizontal oscillation of
the eye is present

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Clinical Features
 Visual acuity decreased
 Crowding phenomenon
 Decreased contrast sensitivity
 Decreased accommodation
 Decreased visual field

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Crowding phenomenon
 Amblyopes can discriminate smaller visual
acuity symbols when presented singly
E O

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Investigations
 History
 Visual acuity testing
 Fixation evaluation
 Perfect refraction
 Eye disease evaluation
 Visual field testing
 Neutral density filter
 Test of retinal function
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Fixation evaluation
 Central fixation
 Eccentric fixation
 No fixation
Foveal Para foveal Macular Peripheral
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Neutral Density Filter
 Reduce vision in eyes with central retinal
lesions and glaucoma
 Kodak Wratten Filter No.96

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Amblyopia Therapy
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Amblyopia Therapy
1. Removal of ocular pathology
2. Full refractive correction
3. Occlusion therapy / Penalization therapy
4. CAM vision stimulator
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Cont………
5. Auxiliary therapy for eccentric fixation
6. Prescription of appropriate maintenance
programme
7. Periodic visit
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Occlusion Therapy
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 Attach with spectacle
 Occlusion with black cloth
 Attach with skin
 Opaque contact lens

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Types
 According the area of visual field occluded
 According which eye occluded
 According the effect of light transmission
 According the occlusion time
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 Degree of amblyopia
 Age of the patient
Required time

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Maintenance therapy
 Patching for 1-3 hours per day
 Penalization with atropine 1 or 2 day per
week.
 This may require periodic monitoring until
age 8-10 years

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Risk of Occlusion Therapy
 Full time occlusion requires close
monitoring, especially in the younger child
 The first follow up visit after initial
treatment should occur within 1 week
 Part time occlusion method allows for less
frequent observation

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Reality
 Poor cooperation
 Underlying organic defect
 Started too late
 Grossly unequal eyes (unilateral high myopia -
unilateral aphakia)
 Latent nystagmus

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Children with sensitive skin
 Tincture of benzoin is applied before
occlusion

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Penalization therapy
 Near
Good eye : Atropine 1% + full correction
Amblyopic eye : +3.00Dsph over correction
 Distance
Good eye : Atropine 1% + +3.00Dsph add
Amblyopic eye : full refractive correction
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Cont………
 Total
Good eye : Atropine 1% + plano lens
Amblyopic eye : full refractive correction
Good eye : Atropine 1%
Amblyopic eye : Pilocarpine 2%
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CAM Vision Stimulator
 Campbell and coworkers in 1978
 Stimulation by slowly rotating high
contrast, square wave grating for 7 min.

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Auxiliary therapy for eccentric
fixation
 Pleoptics
 Inverse prism therapy
 Red filter therapy

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Pleoptics
 Patch amblyopic eye for 1-2 months
 Bangerter’s method
 Pleoptophore
-Bleaching phase
-Stimulating phase
 Cupper’s method
 Ethyscope

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Inverse prism therapy
 Occlude the normal eye totally
 Place an inverse prism before
amblyopic eye
 Shifts the principal visual direction to the
fovea

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Red filter therapy
 Occlude the normal eye totally
 Kodak Wratten Filter No. 92 (640nm) is
placed before amblyopic eye

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Thank
you…