BHUBANESWAR
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
BHUBANESWAR
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
BHUBANESWAR
BHUBANESWAR
BHUBANESWAR
Classifications Stimulus deprivation amblyopia Strabismic amblyopia Anisometric amblyopia Isometric amblyopia Occlusion amblyopia Secondary due to nystagmus
BHUBANESWAR
BHUBANESWAR
Stimulus deprivation amblyopia Severe ptosis
Corneal opacity
Congenital Cataract
Vitreous opacity BHUBANESWAR
BHUBANESWAR
Strabismic amblyopia Due to unilateral squint it develops as an
adaptation to avoid diplopia
Most commonly seen in esotropia
BHUBANESWAR
BHUBANESWAR
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
BHUBANESWAR
Anisometric amblyopia Significant difference in
refractive error between two eyes
Hypermetropia is more intense than myopia
BHUBANESWAR
BHUBANESWAR
Isometric amblyopia Secondary to approximately equal high
refractive errors in both eyes
Hypermetropia is more intense than myopia
BHUBANESWAR
BHUBANESWAR
Occlusion amblyopia
Prolonged occlusion therapy of preferred eye
BHUBANESWAR
BHUBANESWAR
Secondary to Nystagmus Latent or manifest nystagmus may decrease
vision
In micronystagmus horizontal oscillation of the eye is present
BHUBANESWAR
Clinical Features Visual acuity decreased Crowding phenomenon Decreased contrast sensitivity Decreased accommodation Decreased visual field
BHUBANESWAR
Crowding phenomenon Amblyopes can discriminate smaller visual
acuity symbols when presented singly
E O
BHUBANESWAR
Investigations History Visual acuity testing Fixation evaluation Perfect refraction Eye disease evaluation Visual field testing Neutral density filter Test of retinal function
BHUBANESWAR
BHUBANESWAR
Fixation evaluation Central fixation Eccentric fixation No fixation
Foveal Para foveal Macular PeripheralBHUBANESWAR
BHUBANESWAR
Neutral Density Filter Reduce vision in eyes with central retinal
lesions and glaucoma
Kodak Wratten Filter No.96
BHUBANESWAR
Amblyopia Therapy 1. Removal of ocular pathology
2. Full refractive correction
3. Occlusion therapy / Penalization therapy
4. CAM vision stimulator
BHUBANESWAR
BHUBANESWAR
Cont………
5. Auxiliary therapy for eccentric fixation
6. Prescription of appropriate maintenance programme
7. Periodic visit
BHUBANESWAR
BHUBANESWAR
Occlusion Therapy
BHUBANESWAR
Attach with spectacle
Occlusion with black cloth
Attach with skin
Opaque contact lens
BHUBANESWAR
Types According the area of visual field occluded
According which eye occluded
According the effect of light transmission
According the occlusion time
BHUBANESWAR
BHUBANESWAR
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
BHUBANESWAR
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
BHUBANESWAR
Reality Poor cooperation Underlying organic defect Started too late Grossly unequal eyes (unilateral high myopia -
unilateral aphakia) Latent nystagmus
BHUBANESWAR
Children with sensitive skin
Tincture of benzoin is applied before occlusion
BHUBANESWAR
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
BHUBANESWAR
BHUBANESWAR
Cont……… Total Good eye : Atropine 1% + plano lens Amblyopic eye : full refractive correction
Good eye : Atropine 1% Amblyopic eye : Pilocarpine 2%
BHUBANESWAR
BHUBANESWAR
CAM Vision Stimulator
Campbell and coworkers in 1978
Stimulation by slowly rotating high contrast, square wave grating for 7 min.
BHUBANESWARBHUBANESWAR
Auxiliary therapy for eccentric fixation Pleoptics
Inverse prism therapy
Red filter therapy
BHUBANESWAR
Pleoptics Patch amblyopic eye for 1-2 months Bangerter’s method
Pleoptophore-Bleaching phase-Stimulating phase
Cupper’s method Ethyscope
BHUBANESWAR
Inverse prism therapy Occlude the normal eye totally
Place an inverse prism before amblyopic eye
Shifts the principal visual direction to the fovea
BHUBANESWAR
Red filter therapy Occlude the normal eye totally
Kodak Wratten Filter No. 92 (640nm) is placed before amblyopic eye