3. Definition
• Amblyopia is a vision development disorder in
which an eye fails to achieve normal visual
acuity, even with prescription eyeglass ® contact
lens. Also called “Lazy eye”.
• The best corrected visual acuity poorer than 6/9
in absence of the ocular media and fundus
anomalies ® ocular disease.
4. • Amblyopia begins during infancy and early
childhood. In most cases only one eye is affected.
• A unilateral / bilateral condition.
16. Strabismic Amblyopia:
It is seen in patient having squint since birth unilateral constant
squint who strongly use one eye for fixation .It is more common
in esotropes.
Example:
A patient has Right Estropia
Vision RE: 2/60 NIG NIP
LE: 6/6 NIL GLASS.
In this case the patient will prefer only the left eye for
fixation.
17.
18. Anisometropic Amblyopia:
one eye having higher refractive error than the other eye. It occurs more
hypermetropia than in myopes.
Hypermetropic Amblyopia - More than 2-3Diopters
Myopic Amblyopia - More than 5 Diopters
EXAMPLE:
RE:6/6 NIL GLASS
LE:6/60 +3.00 DSPH 6/24 NIG NIP (Left eye anisohypermetropia)
EXAMPLE:
RE:3/60 -9.00/-1.00DCYL 90 6/36 NIP
LE:6/9P -0.75 DSPH 6/6 (Right eye Anisomyopia)
19. Ametropic Amblyopia:
Occurs in patient with bilateral un corrected high refractive error.
Hypermetropia of more than +5.00D
Myopia of more than -10.00D
Example:
RE 5/60 +7.00 DSPH 6/36 NIP
LE:4/60 +8.00 DSPH 6/36 NIP.
Example:
RE 6/60 -11.00 DSPH 6/18 NIP
LE 2/60 -12.00 DSPH 6/18 NIP
20. Stimulus deprivation amblyopia :
It can be unilateral ( r ) bilateral and complete (r )
partial depending upon the amount of light entering the
eye. This is caused by any opacity in the media.
EXAMPLE:
1.Ptosis ( Drooping of upper eye lid)
2.Corneal opacity
3.cataract
21.
22. Meridional amblyopia:
Occurs in patient with un corrected astigmatic
refractive error. It can be bilateral.
EXAMPLE:
RE: 6/12 -1.00 DCYL 180 6/6
LE : 6/60 -4.00 DCYL 180 6/18 NIP
(LE: Meridional amblyopia)
29. Bruckner Pupillary Red Reflex Test
• This is a screening test does not measure the
size of deviation .It is performed with the help of
a Direct Ophthalmoscope.
• Patient is made to look into the light and
examiner compares the brightness of pupillary
Red reflex of both eyes obtained simultaneously.
30. • In Orthophoria the Bruckner red reflex is
symmetric in the two eyes.
• In a strabismus the reflex is brighter in the
deviated eye.
31. Refraction
Cycloplegic Refraction:
• Spasm the ciliary muscle to in active the
accommodation by using drug.
• Usually more hyperopic and more
astigmatic eye for the amblyopic eye.
32.
33. Crowding Phenomenon
• Crowding phenomenon, also known as
separation difficulty ,refers to the inability of an
amblyopic eye to distinguish letters (® other
symbols) crowded together.
• Therefore, the vision in an amblyopic eye is
better, when tested with Isolated optotypes than
when tested with line ® Snellens acuity charts
having rows of letters.
34.
35.
36. • In other words, single optotypes visual acuity is
better than linear visual acuity. The larger the
discrepancy between the linear and single letter
acuity, the poorer the prognosis.
• Crowding phenomenon is the result of contour-
interaction between the neighbouring test
targets because of decreased lateral inhibition in
amblyopia.
37. Neutral Density Filters
• Patients with Strabismic amblyopia may have better
visual acuity ® less of a decline of visual acuity when
tested with neutral density filters compared to the
normal eye.
• Whenever possible, it is imperative to illucidate this
important characteristic of amblyopic eye-that the
amblyopic eye sees better under mesopic conditions
(between scotopic and photopic condition).This can be
tested with neutral density filter test.
38.
39. Neutral Density Filter Test
• In this test, visual acuity is measured without and
with neutral density filter placed in front of the
eye.
• Difference between functional &organic
amblyopia
• In cases with functional amblyopia visual acuity
slightly improves while in organic amblyopia it is
markedly reduced when seen through the filter.
40. Effect of Neutral Density Filter
• It has been reported that when visual acuity is tested
with a neutral density filter placed in front of the
affected eye, the visual acuity improves by one ® two
lines in patients with developmental amblyopia; while
in patients with organic amblyopia, the visual acuity
decreases by two to three lines .
• Therefore, the neutral density filter test has been
recommended to differentiate between developmental
amblyopia and organic amblyopia.
41.
42.
43. • The neutral density filter test is based on the fact that
under photopic conditions, visual acuity of amblyopic
eye is less than that under scotopic conditions.
• Since the neutral density filter, when placed in front of
an eye, produces a state of scotopic conditions, the
vision of amblyopic eye improves.
44.
45. Goal of Treatment
• To restore and improves visual acuity. Present
clear retinal image to the amblyopic eye.
• Make the child use the amblyopic eye.
46. Optical Correction
• To provide sharp images and providing optimal
environment for amblyopia therapy.
• Give patient proper optical correction alone,
short period of time (6-8 weeks) before
initiation of other therapy.
47. Occlusion
• In this therapy the amblyopic eye is given a
preferential chance of development as the
dominant eye is totally with held from the
binocular participation.
• A properly done occlusion with good
compliance ensures an almost 100% success
rate ,especially if treated up to 7 years age.
48.
49. Amelioration of amblyopiogenic factor
(proper visual rehabilitation)
• This is required prior to occlusion therapy this may
be the therapy for Ametropic amblyopia which do
not require occlusion ,unless there is a difference in
vision in the two eyes (Due to Anisometropia ®
strabismus associated)
50. A. Types of occlusion
A totally opaque patch can be used in different forms .
1.Direct skin Patch :
• A cotton eye pad patched to the eye with the help of
micro pore plaster (two inch width). The micro pore
tape allows sweating and is better accepted.
• Commercially available “Opticlude” ® Coverlet" are too
expensive so also are the commercially available eye
pads .simple eye pads can be made at home for daily
use.
51.
52. 2.Spectacle Patch:
• One glass is made opaque by applying plaster and
opaque paper on front and back.
• A slight extension of the same is made on the lateral
side of the glass to prevent side “peeking”
3.Doynes Occluder :
• A black rubber Occluder which sticks on the back of the
spectacle glass by suction can also be used.
4.Pirate patch:
• A black cloth stitched like a pirate patch is preferably
sported by some children.
53. 5.Contact lenses:
Which are opaque can be used by children who want to
avoid the look of an occlusion patch. The tolerance of
contact lens is an additional factor and it needs to be
worn for full waking hours for good effect.
54. B.Partial Occlusion
• This is a form of penalization and is used for milder amblyopia ® in
recovered cases for maintenance of binocular vision.
• It also requires correction of factors like squint Anisometropia (r )
Aniseikonia suitably.
• The advantage over total occlusion of this modality is that it offers
binocular stimulation.
• Frosted glass,Layer of transparent scotch tape ® color less nail
varnish can be applied on the back surface of the glass of
dominant eye.
55. (a) Full time Occlusion:
All waking hours virtually 24 hours.
(b) Part time Occlusion:
• This is for graduated duration different waking hours of
the day on the basis of age of the child.
Duration of occlusion:
• 2 Days up to 2 years old
• 3 Days for 3 years old
• 4 Days for 4 years old
• 5 Days for 5 years old
• 6 Days for 6 years old and above
56. • This is alternated with one day of occluding the
amblyopic eye when the dominant eye is opened
At no time are both eyes opened to gether.
• Occlusion of dominant eye is called conventional
occlusion and the occlusion of the amblyopic eye
is called inverse occlusion.
57. Follow up
• The course of occlusion is continued till the vision keeps
improving or the vision does not improve on two consecutive
monthly visits (provided compliance is good) .The latter is termed
occlusion failure.
• Usually occlusion yields results in 3 months period.
• Patient not coming for follow but continuously patching then
Normal eye can become amblyopic.
Follow up period depends upon the eye and type of occlusion
therapy.
58. 3.Penalization
• This is a form of partial occlusion where by the
amblyopic eye is forced to a greater use while the
normal eye is disadvantaged .This may be done by
(i) Optical Penalization:
Over correcting with plus glasses (disadvantage for
distance)
(ii) Pharmacological Penalization:
Using Cycloplegics (disadvantage for near)
(iii) Partial Occlusion by cello tape ® Nail varnish
(disadvantaged for both distance and near)
60. CAM Visual Stimulator
• This apparatus was designed by Campbell and his co-
workers to treat amblyopia by intense visual stimulation
for short period of time.
• Gratings of different spatial frequency are rotated in
front of the amblyopic eye while the other eye is
occluded.
• This method was based on the knowledge that cortical
cells respond to specific line orientations and to certain
spatial frequencies.
61.
62. • Therefore rotation of gratings different spatial
frequencies ensured that a large range of
cortical neurons was stimulated.
• Better for Anisometropic Amblyopia.
63. Intermittent Photic Stimulation
• Mallet IPS unit
• Red slight stimulation at 4Hz
• Visual Task 20-30 minutes
• The targets consisted of slides containing
much detail of varying type and angular
dimension.
• Viewed against a red flickering back ground
64.
65. Pleoptics
• This treatment was to eradicate the eccentric
fixation.
• Apparatus based on the ophthalmoscope principle
(Euthyscope, Projectoscope,Pleutophore).
• Exposed the peripheral retina to very bright light
while protecting the macular area.
• Only suitable for children 7 years old.
66.
67. Red Filter Treatment
• Red filter treatment for the improvement of
fixation and visual acuity in amblyopia with
eccentric fixation.
• Total occlusion of sound eye with Red filter
Kodak gelatin wratten filter, wave length 600-
640nm on glass before amblyopic eye.
• Cuts out white light.
68.
69. Red Filter Treatment
• Red light incapable of stimulating eccentric
fixation.
• The red filter was kept on the amblyopic eye for
6-14 weeks, during which period several hours
daily were spent in performing exercises ®
playing games.
70. Medical Treatment
• Levodopa /Carbidopa has been traditionally used
to treat Parkinson's disease.
• Levodopa is a precursor for the catecholamine
dopamine,a Neuro transmitter/ Neuromodulator
known to influence receptive fields.
• Levodopa / Carbidopa has been studied as an
adjunct to patching for the treatment of
amblyopia.
71. Surgery
If amblyopia is due to:
• Cataract Cataract surgery.
• Non clearing vitreous opacities Vitrectomy.
• Corneal opacities Corneal graft.
• Blepharoptosis tarsal tuck
