Post on 09-Apr-2017
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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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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 BHUBANESWAR
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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 PeripheralBHUBANESWAR
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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 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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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