All about active and passive therapy in amblyopia management

1. Active & Passive therapy in
Amblyopia Management
Presenter : Moderator:
Bipin koirala Hira Nath Dahal
Maharajgunj Medical Campus Institute of Medicine
Tribhuvan University

2. Presentation layout:
Introduction
Passive therapy
Active therapy
Therapy in eccentric fixation
Summary
References

3. Introduction:
Derived from Greek word (Amblyos : Dullness/Blunt ; Ops : Vision)
U/L or less commonly B/L reduction in BCVA that cannot be attributed
directly to the affect of any structural abnormality of the eye or the posterior
visual pathway
Main cause of decreased vision in childhood
Difference of >2 lines between 2 eyes

4. Risk factors of Amblyopia:
4 times more prevalent in LBW & premature baby
6 times more prevalent in delayed milestone & CNS disorders
Smoking & use of Drugs & alcohol during pregnancy have been a/w risk of amblyopia

5. Sensitive Period:
The capacity of the visual system to develop amblyopia is limited by its state of maturity.
During immaturity of the visual system the retinocortical connections are not firmly
established and may be modified by the quantity or quality of the visual input
This phase has been described as the sensitive, critical, or susceptible period
 The human is most sensitive to environmental manipulation during the first 2 years of
life
The human critical period is over by approximately 7 to 9 years of age

6. Classification:
Functional amblyopia Organic amblyopia
Reversible Irreversible
Refers to obligatory psychical
suppression of the retinal image
Refers to partial loss of vision caused
by undetectable organic lesions in
the eye or in the visual pathway
Can be : Strabismic , Ametropic ,
Anisometropic , Meridional ,
Stimulus Deprivation
Can be : Nutritional , Toxic , d/t
Retinal diseases , Idiopathic
Usually in Childhood Can cause VA defect at any age

7. Pathophysiology:
Amblyogenic factors
Role of Retina
Active cortical Inhibition

8. Classification & types:
Strabismic amblyopia
Stimulus deprivation or amblyopia of disuse
Anisometropic amblyopia
Meridional amblyopia
Isometropic amblyopia
Amblyopia secondary to nystagmus
Idiopathic amblyopia
Organic amblyopia

9. Management of Amblyopia:
Vision screening programs should be done.
I-ARM test ( Inspection- Acuity, Red reflex & Motility)
Bruckner’s red reflex test is vital for screening.
Cataract:- white reflex
Retinoblastoma:- yellow-white reflex
Anisometropia:- unequal red reflex
Strabismus:- brighter red reflex
Prevention & Early detection Treatment of amblyopia

10. Goal of treatment:
To restore and improve visual acuity by two strategies:
I. Present clear retinal image to the amblyopic eye
 Eliminate causes of visual deprivation
 Correcting visually significant refractive errors
II. Make the child use the amblyopic eye
Recommended treatment should be based on
Pt.’s age, VA, compliance with previous treatment & physical, social and psychological
status

11. What would be the perfect Amblyopia therapy?
 Effective
 Good compliance
 Acceptable to pts. and parent
 Quick
 Safe
 Easy to administer
 Cost effective
 Well maintained

12. Treatment of Amblyopia
Goals
Monocular goals
 Eliminate eccentric
fixation
 Eliminate eccentric
localization
 Establish foveal
fixation
 Establish foveal
localization
 Improve visual acuity
Binocular goals
 Eliminate sensory
anomalies
 Improve sensorimotor
visual skills
 Stabilize binocular
vision in open space
VS

13. Basic 3 Strategies to treat Amblyopia:
1. Eliminate cause of visual deprivation & provision of clear retinal image in
amblyopic eye.
2. Correction of ocular dominance
3. Perceptual training

14. Media clearance (For clear Retinal image):
Childhood cataract, severe congenital ptosis & corneal opacity should be treated as
early as possible to prevent stimulus deprivation amblyopia.
Significant congenital cataract should be removed during 1st 2-3 month of life.

15. In symmetric bilateral cases , interval between operation should not be more than 1-2
weeks.
Acutely developing severe traumatic cataract in child < 8-10 yrs should be removed
within few weeks of injury.
Refractive correction for aphakia should be given without delay.

16. Correction of ocular dominance:
Passive Therapy:
The patient experiences a change in visual stimulation without any conscious effort
1. Proper refractive correction
2. Occlusion
3. Penalization
4. Pharmacological manipulation

17. Active Therapy:
It is designed to improve visual performance by the patient’s conscious involvement in a
sequence of a specific, controlled visual task that provide feedback.
1. Pleoptics
2. Near activities
3. Active stimulation therapy using CAM vision stimulator
4. Syntonic phototherapy
5. Role of perceptual learning
6. Binocular stimulation
7. Software-based active treatments

18. Refractive correction
Occlusion therapy/ Patching
Penalization method
Commonest Passive therapy procedures :

19. Refractive Correction:
To provide sharp images and providing optimal environment for amblyopia therapy
Give pt. proper optical correction alone - Short period of time (6-8 weeks) before
initiation of other therapy
In case of refractive amblyopia , a progressive improvement in acuity for up to 16 - 22
weeks has been shown in some pts. after refractive correction (Stewart C. et al 2004)

20. Summary table for power prescription in
various pediatric age group by AAO

21. Refractive correction (contd..)
Improves VA in 25-33% of patients with Anisometropic amblyopia and also in Strabismic
Amblyopia
Chen et al (AJO 2007) concluded that amblyopia improved with optical correction in 93%
and resolved in 45%
Penalization and occlusion is required only if the VA doesn’t improve with glasses for 4
months

22. Refractive Correction according to ATS ( Amblyopia Treatment Study)
• ATS - 5 (PEDIG) 2006 concluded that in case of anisometropic amblyopia in children's
b/w 3 -7 yrs of age improved with optical correction alone in 77% and resolved in
27%
• ATS 5 (2) says first after a certain period of treatment with specs 2 hours of daily
patching combined with 1 hour near activity will be effective for moderate to severe
amblyopia of 3-7 yrs childs.
• ATS-7(PEDIG) Treatment of bilateral refractive amblyopia with spectacle correction
improves binocular VA in children (3-10yrs) from (6/120 – 6/12) to even upto 6/7.5
with in 1 yrs period.

23. Occlusion therapy:
Passive treatment
Occlusion of the sound eye is the most effective treatment for amblyopia treatment
by forcing the patient to use the amblyopic eye.
Mainstay of treatment since 18th century to till now.
Highly effective until 8 years of age.

24.  Causes progressive changes in Visual functioning.
 Success rate 30-92%
1. When fixation is central: simple & effective
2. When fixation is eccentric: <7yrs central fixation recover
3. Older the child harder to regain central fixation

25. Mode of Action:
Prevent fixating eye taking part in act of vision and removes inhibitory stimulus that
arises from stimulation from fixating eye (non-amblyopic eye)
Occlusion goals:
1. Differential diagnosis
2. Improvement of amblyopia
3. Elimination of suppression
4. Awareness or elimination of diplopia
5. Disruption of anomalous correspondence.

26. Various types of Occlusion
Occlusion
Total or Partial
Conventional or
Inverse
Full Time or Part
Time

27. Total Occlusion vs Partial Occlusion
Total occlusion Partial (light transmission)
•All light is prevented from
entering eye
•Employed in amblyopic eyes
with acuity less than 6/24
•Occlusion using elastoplast, gauze pad,
tape, doynes rubber occluder
•Does not cut off the total light
entering eye
•Degrades the vision of normal
eye such that amblyopic eye
gets better vision and
preference
•Occlusion using cellophane,
transparent nail polish, or a
higher plus lens

28. Partial /translucent
occlusion Total Occlusion
Given in
Nystagmus
Amblyopia
treatment

29. Conventional or Direct occlusion Inverse occlusion
 Occlusion of sound eye
 Foveal or unsteady eccentric
fixation is present in amblyopic eye.
 Occlusion of amblyopic eye so that
eccentric fixation becomes less
fixed.
 Steady eccentric fixation
Conventional vs Inverse occlusion

30. Direct Occlusion:
Patch the good eye
Stimulate Amblyopic eye
Indication for
1. Deprivation Amblyopia
2. Anisometropic Amblyopia

31. Inverse occlusion:
For amblyopia associated with EF (Strabismic Amblyopia)
Patching the amblyopic eye to weaken eccentric fixation of amblyopic eye.
If children is under 5 year old age
1. Direct full time occlusion may risk
2. Do direct occlusion alternate with inverse occlusion
3. I.e. For 3 years old children, may need 3 days direct and 1 day indirect occlusion
consider 1 cycle and repeated period of time

32. Additional points:
Inverse occlusion is prescribed whenever occlusion is needed but direct occlusion is
intolerable to the patient.
Given only if the patient is strongly resistant to direct occlusion.
For example:- A strabismic patient with deep amblyopia may not be able to perform needed
visual tasks with amblyopic eye. So 1st inverse occlusion is started & changed to direct
occlusion once more central fixation and improved visual acuity are obtained
Inverse occlusion is started first to introduce the hesitant patient to a patching regime.

33. Full Time occlusion vs Part Time occlusion
Full time occlusion Part time (Intermittent) occlusion
 Removed only while going to bed at night
i.e. all waking hours.
 Short time each day during close work.
commonly( 1-6 hrs/day)
 Choice of initial Rx  In relapses after Rx and also for
maintenance
 Given for constant strabismic Amblyopes.
(regardless of size of deviation)
 Given for intermittent strabismics or non
strabismic amblyopes

34. Patching according to Amblyopia Treatment Study:
• ATS 2 A concluded that full time patching is equally effective as part time patching
of 6hrs in children's of age below 7yra and visual acuity of range 6/60 to 6/120.
• ATS 2B concluded 2hours patching is equally effective as 6hrs patching in moderate
amblyopia( visual acuity (6/12 to 6/24)

35. Some exceptions to General rule:
Constant Exotropic patients who change quickly to an intermittent strabismus with
therapy ,instead of full time occlusion may need only part time occlusion or even no
occlusion.
Some non strabismic amblyopes with dysfunctional binocular vision may need minimal to
no occlusion esp when amblyopia is treated actively with simultaneous improvement of
sensorimotor processing.(Cohen 1981; Pickwell 1976)
In infants & toddlers< 2 yrs of age, d/t greatest plasticity in neural processing system, to
prevent occlusion amblyopia, maximum 2 hrs/day is given & passive lens, prism therapy is
given together with active therapy.

36. Contd..
Occlusion in Intermittent Strabismus:
Time of occlusion depends on patient’s level of sensorimotor skills.
Since constant occlusion may break down binocular skills only part time occlusion is
recommended.
When not wearing patch patient’s existing binocular skills can be reinforced through
passive therapy & sensory anomalies such as suppression can be eliminated when
wearing patch.

37. Contd…
In intermittent strabismics,part time occlusion eliminate central or foveal suppression &
treat shallow amblyopia eye after binocularity is achieved.
Non strabismic anisometropes or intermittent strabismic with deep amblyopia requires
most hours of part time general occlusion
Intermittent strabismics with good peripheral sensorimotor fusion & shallow or no
amblyopia requires least hours of part time general occlusion.

38. Occlusion in Constant Strabismus:
Earlier, full time occlusion followed by a day of rest was advocated. This allows
constant strabismus to regress to anomalous strabismic visual processing on free day.
Nowadays, full time occlusion is prescribed initially. When intermittency is achieved
in open space ,part-time occlusion is given allowing some reinforcement of binocular
skills in normal activities.

39. Points on Occlusion
The presence (or absence) of amblyopia and its fixation pattern determine
which eye to patch
The frequency of strabismus determines the amount of time that the eye is
patched

40. Alternate occlusion:
When equal visual acuity is present in each eye (Example: A constant alternate
esotropia) , full time occlusion is alternated daily between two eyes.
The purpose of full time occlusion for strabismic with no amblyopia is to eliminate
suppression and possibly disrupt anomalous correspondence.

41. Field Coverage:
Depends on how much of the visual field to block
Either the visual stimulation is blocked to whole visual field (total occlusion) or just to
specific portions of the visual field (partial occlusion) (d/t presence and frequency of
strabismus in a specific gaze or distance)
Other consideration is whether to cover both peripheral and the central retina or just
the central retina of the deviating eye.

42. Terminology Indication Visual field coverage
Total Constant strabismus at all distances & gazes Full field
Half- patch Constant strabismus at one distance &
intermittent or heterophoria at other.
Distance or near field
Sector patches Incomitant strabismus. (intermittent in one
field of gaze & constant in other)
 BSV remain in non affected & non
occluded field
 Anomalous sensory processing can be
disrupted or diplopia can be eliminated in
affected field
 Achieve goal of binocular therapy
sequence
Selected gazes
Field Coverage Occluder:

43. Terminology Indication Visual field coverage
Binasal Constant Esotropia Nasal fields( temporal retina)
Bitemporal Constant Exotropia Temporal fields(nasal retina)
• Bipatches block the visual stimulation to a specific retinal region of
nonfixating eye which under unoccluded conditions would receive anomalous
visual stimulation d/t turning of eye.
• Both trigger alternation in viewing to amblyopic eye, leading to improved
visual acuity or elimination of foveal suppression.
• Both are alternate to total occlusion.
• Bitemporal occlusion disturb panoramic vision. So, not much favored.

44. Bitemporal patches
Binasal patches
Sectoral occlusion

45. Age of patient (in yrs) Period of occlusion
(days)
Direct vs Inverse
Follow up after every
Up to 2 2 : 1 15 days
3 3 : 1 15 days
4 4 : 1 1 month
5 5 : 1 1 month
6 or older 6 : 1 1 month
A simplified schedule for initial occlusion therapy for amblyopia
Reference: Squint and Orthoptics by A.k. Khurana

46. How to go about Occlusion?
Compliance is the keyword of success. Motivation of child and parents is necessary.
First the near vision then distance vision starts improving.
Active vision exercises by amblyopic while non- amblyopic eye is occluded
Occlusion is continued till amblyopic eye has developed equal vision and equal
preference of fixation
May take 3-6 month
If there is no improvement, on three consecutive monthly follow ups then treatment is
stopped, reevaluation is done.
Incomplete response to occlusion tends to be associated with anisohypermetropia &
anisoastigmatism.

47.  Follow up-depending on age, severity of amblyopia and compliance to look for VA,
fixation pattern and occlusion amblyopia
 When to stop occlusion
- VA equals in both eyes
- Alternation of fixation (Repka 2008)
 When VA is stable patching may be decreased slowly
 Because amblyopia recurs in large no. of pts. maintenance therapy or tapering of
therapy should be strongly considered

48. Disadvantages of Occlusion:
Occlusion amblyopia
Psychological distress
Allergic skin rash
Cosmetically inacceptable
Strabismic diplopia
Deviation changes

49. Treatment of Anisometropic Amblyopia:

50. Treatment of Strabismic Amblyopia

51. Penalization:
Is a form of partial occlusion whereby the amblyopic eye is forced to a greater use while
the normal eye is disadvantaged
May be done for distance/near/total depending on the severity of amblyopia
May be done by Optical penalization-overcorrecting with plus glasses (blur for far),
Pharmacological by using cycloplegic (blur for near)

52. Better accepted by patients and parents
Offers binocular stimulation
Offers binocular stimulation, useful for non strabismic milder amblyopias, maintenance
of regained BSV and VA

53. Uses selective blurring rather than occlusion
Goal is to have the px use amblyopic eye for particular distance and the nonamblyopic
eye for other distance.
Lesser success rate than Occlusion therapy in moderate and deep amblyopia
Total four modalities of penalization namely Near/Distance/Total/Alternating.

54. Types of Penalization:
Near penalization- the fixing eye is atropinized and fully corrected, while the
amblyopic eye is overcorrected by +2.00 to +3.00 D encouraging the amblyopic
eye to be used for near
Tries to establish alternation of the two eyes, one for near and one for distance
fixation

55. Far penalization- the fixing eye is atropinized and overcorrected with a + 3.00 D
lens to be used for near, while the amblyopic eye is fully corrected and used for
distance.
Total penalization- the fixing eye is atropinized and under corrected 4.00 to 5.00 D
by using minus lenses or decreasing the hyperopic correction preventing the
fixating eye from being used at near or far. The amblyopic eye fully Corrected and
fixates for near and distance.

56. Alternate Penalization: Two pairs of glasses are worn on alternate days, with the first pair
having a +2.00 to +3.00 D overcorrection of the right lens, the second pair a +2.00 to
3.00 D overcorrection of the left lens.
Amblyopic eye is used for near one day and distance the next
Commonly used for maintenance therapy to preserve the visual acuity after successful
treatment

57. Few considerations….
VA of the normal eye should be reduced sufficiently below that of the amblyopic eye
to create an alternation of fixation
Commonly employed in shallow amblyopia(20/60 or better)
Employed when traditional occlusion therapy is not feasible due to various reasons
1 drop of Atropine 1 % instilled daily till the therapy ends.

58. Pharmacological Manipulation :
Studies indicate that plasticity of visual system during the sensitive period Is dependent on
input from non adrenergic neurons and thus can be subjected to pharmacological
manipulation .
Levodopa/ Carbidopa is often used for this purpose. (Parkinson’s dz medication)
Levodopa is a precursor of catecholamine dopamine(neurotransmitter) influencing the
receptive field of neurons.
It remains controversial.

59. Active Vision Therapy
The purpose of amblyopia therapy is to maximize the patient’s performance in
visually related tasks such as academics, sports and driving
Successful treatment can be accomplished and a long term cure sustained if the
emphasis is on developing high degrees of binocular function
The conventional approach of occlusion and full optical correction is rarely, if ever,
needed

60. Active vision therapy for Amblyopia:
•Purpose
• To enhance effects of occlusion (if occlusion at all)
• To decrease total treatment time
• Reduce symptoms
• Improve visual performance deficits
• Most importantly – To maintain gains !!!

61. Primary deficits in Amblyopia :
Deficient eye movement/fixation skills
Unsteady and/or eccentric fixation
Increased saccadic latency and reaction
time for eye-hand coordination
Decreased pursuit accuracy
Poor form discrimination due to
decreased contrast sensitivity
Deficient accommodative skills
Decreased amplitude, accuracy and
decreased sustaining ability
Increased accommodative latency
Spatial uncertainty
Increased contour interaction
Reduced visual information processing
speed and ability

62. Active therapy can be either:
Monocular
Monocular Fixation in a Binocular Field
Binocular

63. Monocular procedures:
Main purpose of Monocular therapy:
Restoring and building visual abilities
Restoring and building confidence and self esteem

64. Establish Central Fixation:
1. Haidinger’s Brushes
Acts a foveal “tag”
Gives bio-feedback to the patient
about where the fovea is pointing
2. After Image Transfer- Acts a foveal tag
Fovea of non-amblyopic eye is monocularly
flashed with AI
Non-amblyopic eye is then occluded
AI transfers to corresponding fovea of the
amblyopic eye
Goal: Place the AI on the monocularly
fixated target
 Only use targets which require fixation at the fovea, or near to the fovea
 Only use targets which don’t allow for adequate performance with the eccentric point

65. Monocular Procedures:
Oculomotor procedures
Pursuits and Saccades
1. Monocular prism jumps
2. Line counting
3. Hart chart saccades
4. Pegboard/Rotator pursuits
5. HTS-amblyopia program
6. Tracking Books
7. Saccadic strips

66. Accommodative Procedures
1. Bulls eye
2. Lens sorting
3. Minus lens (amplitude and facility)
4. Near-far rock
5. Lens flipper facility and power
6. Wachs mental Minus

67. •Eye-Hand Coordination procedures
1. Colouring, cutting, drawing, tracing
2. Stringing beads, cereal or buttons
3. Computer and video games
4. Pegboard activities
5. Sewing, needlepoint, lacing cards
6. Dot-to dot pictures, mazes, Colouring in O’s or crossing out letters
in newspaper
7. “Roadmaps” and Line Tracing
8. Wachs Finger thinking procedures-Paper tear
9. Chalkboard procedures: Roadmaps, line tracing, etc.

68. Form Recognition/Discrimination
Activities that require resolution of details
Emphasis: recognition of form, but complicated with being hidden, briefly exposed or
slightly different from similar comparison form
VT Techniques:
1. Tracking books
2. Word/letter searches
3. Form reproduction
4. Highlights for children magazine: hidden pictures, similarity/difference activities
5. Tachistoscope

69. Don’t forget to work on the good eye, and not just the amblyopic eye
If there are symptoms like blur, loss of place when reading, difficulty
with reading comprehension, etc. Then the symptoms are coming
from the non amblyopic

70. Monocular Fixation in a binocular field
Goal: To reduce non-amblyopic eye’s inhibition of the amblyopic eye
MFBF techniques allow both eyes to see peripheral objects while the amblyopic
eye sees central details
Frequently results in additional visual acuity improvement
Increases the possibility that acuity gains will be maintained
Principle: A unified peripheral field is present to both eyes
A central, highly detailed target is seen only by the eye that is usually suppressed
if the target is seen, then eye that is normally being suppresses is working

72. Binocular:
• Sensory fusion and stereopsis maintain the gains from VT.
• Stereopsis: not just a test of depth perception also a very
sensitive probe into the quality of binocularity
“Stereopsis is the single best indicator of the overall function of both the
sensory and motor portions of the visual system”
J.J Saladin; Borish: Clinical Refraction, 2006
Chapter 21: “The Barometer of Binocularity and Visual Function”

73. “Stereopsis contributes to the judgement of depth and distance and participates in
the recognition of solid objects…as compared with monocular viewing, binocular
vision and stereopsis also help provide better motor control when reaching for a
target or completing fine motor tasks. Stereopsis also provides for quicker and more
accurate cognitive information.”
Daum and McCormack, Borish: Clinical Refraction, 2006, Chapter5: “Fusion and
Binocularity”

74. Aim of Binocular Therapy:
1. Eliminate any remaining suppression under binocular conditions
2. Stress anti-suppression aspects, especially fine central suppression
3. Develop normal sensory-motor function and flexibility
4. Develop and enhance stereopsis

75. Binocular Therapy:
Vision Therapy Techniques:
1. Brock String
2. Vectograms
3. Tranaglyphs
4. Aperture rule
5. Life saver card
6. Computer orthoptics

76. Active stimulation therapy using
CAM Vision stimulator

77. Method:
Non amblyopic eye is occluded
 Amblyopic eye is stimulated for 7 mins by slowly rotating (at about 1 revolution per
min) high contrast square wave grating of different spatial frequencies
The treatment is carried out once in a week for 3 to 4 weeks
Advantages over the conventional occlusion therapy The sound eye remains open
between the weekly treatment sessions

78. Principle:
Assumption that rotating grating provides specific stimulation for cortical neurons
Present status of CAM vision stimulator
 This technique is not as effective as conventional occlusion therapy
So it has failed to replace time tested conventional occlusion therapy for the treatment
of Amblyopia
Some workers use this technique as supplementary to occlusion therapy in co-
operative pts. with supportive who can carry out the treatment at home

79.  Recently a new treatment has been described based on a similar principle, namely, the use
of grating stimuli to activate certain cortical cells (Angelika Shanshinova et al, 2008)
The treatment is computer-based and is intended to supplement occlusion treatment,
particularly in patients beyond childhood
 The treatment comprises a computer game viewed on a monitor against the background of
a low spatial frequency drifting sine wave grating

80. The stimulus is a drifting sinusoidal grating of a spatial frequency of 0.3 cycle/deg and a
temporal frequency of 1 cycle/sec, reciprocally coordinated with each other to a drift of
0.33 deg/sec
 Based on the idea that stimulation of motion-sensitive cells might help to improve
function of form-sensitive cells by synchronisation of responses
 Efficacy of treatment is higher for the computer based method combined with occlusion
than for occlusion only

81. Syntonic phototherapy in the treatment
Amblyopia

82.  Syntonics is the branch of ocular science dealing with the application of selected visible
light frequencies through the eyes
 For the purposes of treatment, Syntonic optometrists define four syndromes as follows:
acute, chronic, emotional fatigue and lazy eye
 In lazy eye syndrome, Amblyopia, strabismus, vergence anomalies, suppression, ARC or
visual field constrictions are treated using red/orange filters

83.  It is based on work by Spitler, in which 2,791 of 3,067 individuals responded positively to
syntonic phototherapy
 However, there is no published studies on the effectiveness of this technique in amblyopia
therapy
In the absence of studies providing good quality evidence that amblyopic patients will be
helped by syntonic phototherapy, there seems to be no basis for prescribing this treatment
Wallace LB. The theory and practice of syntonic phototherapy 2009 Spitler HR. The Syntonic
Principle. Pennsylvania: Science Press Printing Company, 1941

84. Near activities used in the treatment of
Amblyopia

85. Active vision therapies for Amblyopia involve paper-based near activities such as reading,
writing and word puzzles
 Von Noorden and associates (1970) found that minimal (1 hr per day) occlusion combined
with these exercises is beneficial in the treatment of Amblyopia for older children
 The latter studies (PEDIG 2005, 2008) provide high level evidence that the use of near
activities is not helpful in the treatment of Amblyopia
 In the absence of reliable evidence to the contrary, there is not yet a sound basis for
prescribing these tasks for pts. undergoing treatment for Amblyopia

86. Role of Perceptual learning in
Amblyopia treatment

87. Perceptual Learning:
Any relatively permanent and consistent change in the perception of stimulus array
following practice or experience with this array Gibson (1963)
 No. of studies suggest that perceptual learning (PL) may provide an important new
method for treating Amblyopia
Principle:
PL is reported to operate via a reduction of internal neural noise and/ or through
more efficient use of stimulus information by returning weighting of the information

88.  PL employs repeatedly practicing a visual discrimination task, e.g: positional acuity,
contrast sensitivity, stereo-acuity, etc
 Recommended period for PL: 2hrs/ day, 5 days/ week, for a period of 9 months
Significant improvements found in VA and CS (Chen P. et al 2008, Huang C. et al 2006)
 Role of PL is still controversial, but utility is reported in adult amblyopes

89. Video game play and Brain plasticity:
 The intense sensory-motor interactions are immersed video-game play
 This might push brain functions to the limit
 Enables the amblyopic visual system to learn, to recalibrate and adjust, providing
the basis for functional plasticity

90. Game playing requires the allocation of spatial detection, and localization of low contrast,
fast moving targets, and aiming
Video games may include several essential elements for active vision training to boost
visual performance
 According to C. S. Green and co workers (2003) action video game modifies visual
selective attention
 Thus, it could potentially be useful in improving amblyopic vision

91. Binocular stimulation in the treatment
of Amblyopia

92.  During occlusion therapy, the non-amblyopic eye is occluded i.e. binocular vision is
not encouraged during these periods
 It has been recognized that binocular stimulation may be important in the
treatment of amblyopia
 Animal research (Mitchell DE 2008) and recent studies (Baker DH et al 2007,
Mansauri et al 2007) indicate that binocular stimulation encourages binocular
cortical connections during recovery from deprivation amblyopia
 Offers support for binocular stimulation when treating amblyopia

93.  One existing approach to treating amblyopia that allows binocular stimulation is the use
of Bangerter foils ( Baker and colleagues 2007 )
Another long-standing and widely used approach is atropine penalization
 In both cases, the image at the fovea of the non-amblyopic eye is degraded (for near
vision in the case of atropine), while input to the amblyopic eye is not affected
 In these therapeutic scenarios, vision is binocular in the sense that both eyes receive
light stimulation and peripheral resolution is not significantly impeded ( Wang YZ et.al
1997 )

94. Comparisons between occlusion and atropine (LI T et al 2009) or between occlusion
and Bangerter foils (PEDIG 2010) as treatments for amblyopia show no significant
difference in outcome
 Suggests that this type of binocular stimulation does not offer significant
advantages over the combination of binocular and monocular vision allowed by
periods of occlusion

95. The ‘monocular fixation in a binocular field’ (MFBF) technique:
Introduced with the intention of training the amblyopic visual system to integrate
information from both eyes (Cohen AH. Monocular fixation in a binocular field. J Am Optom
Assoc 1981)
This technique involves the presentation of peripheral stimuli to both eyes, while only the
amblyopic eye is stimulated at the fovea

96. Applied in a range of paper-based formats.
E.g, pt. may be instructed to complete tasks such as crossword puzzles or
placing dots in the ‘o’ letters in a text, using a pen and wearing red-green
glasses, with the red lens in of the non-amblyopic eye (wick b.et al 1992)

97. I-BiT Interactive Binocular Treatment for Amblyopia
Concept:
Present separate images to each eye
Dynamic visual scene
Preferentially stimulating amblyopic eye
Patient motivation:
Interactive games and videos
Encourage patient compliance
Shutter Glasses Technology :
Shutter glasses
High definition screens
Faster processing speeds

98. Adaptations for use with the I-BiT system
Shutter glasses with I-BiT software is to change the ratio of
information presented to each eye in order to stimulate one eye
more than the other
This creates a 2D view rather than the intended 3D stereoscopic
view

99. Evidence:
Six children treated with prototype and gained 2 lines of vision (Waddingham et.al Eye
2006 )
10 treated with I-BiT and improvement of 0.189 logMAR, almost 2 lines ( Herbison et al
Eye 2013 )
Other groups: e.g. Hess’s group with the game Tetris in adults (required a minimum
of 6 hrs play before any effect is discernible)

100. Software-based Active treatments for Amblyopia for use at
home or in office

101. The Ambopia iNet program for the treatment of
Amblyopia
 Marketed by Home Therapy Solutions
 System features 12 treatment programs, 6 of which are randomly assigned for
completion by the patient each 5 days per week
 Involve activities like ‘letter jump’, among others
 The treatment involves visual search of certain target

102.  Treatment system is designed to improve hand eye coordination, VA, crowding effect
and visual memory
 No published reports of clinical trials of this method, so it is not possible to know
whether the design is effective as part of a treatment for Amblyopia
 Thus, controlled trials of this treatment are needed (Cooper J. et al 2007)

103. Binocular ipad game vs part time patching
2 studies (PEDIG 2016), (K.R. Kelly et al 2016) were done to compare VA
improvement in children with amblyopia treated with a binocular iPad game vs
part-time patching
 Effect of a Binocular iPad Game vs Part - time Patching in Children Aged 5 to 12 Years With
Amblyopia A: Randomized Clinical Trial;Jonathan M. Holmes et; for the Pediatric Eye Disease
Investigator Group, JAMA Ophthalmology, November - 3, 2016
 Binocular iPad Game vs Patching for Treatment of Amblyopia in Children:A Randomized Clinical
Trial; Krista R. Kelly, PhD; Reed M. Jost , MS; Lori Dao, MD; Cynthia L. Beauchamp, MD; Joel N.
Leffler , MD; Eileen E. Birch, PhD, JAMA Ophthalmology, December 2016

104. PEDIG 2016
VA improves with binocular game play and with patching, particularly in younger
children (age 5 to <7 years)
 VA improvement with this particular binocular iPad treatment is not as good as with 2
hrs of prescribed daily

105. K.R.kelley et al 2016
High-contrast red elements (miners and fireball) are seen by the
amblyopic eye
 Low-contrast blue elements (gold and cart) are seen by the fellow eye
Gray elements (rocks and ground) are seen by both eyes
Both eyes must see the game for successful play

106. Binocular iPad game is a successful treatment for childhood amblyopia and is more
effective than patching at the 2-week visit

107. Treatment of Amblyopia with Eccentric
fixation

108. 1.Inverse Occlusion
Constant total occlusion worn on the amblyopic eye to prevent any further stimulus of
the eccentric point and to dislodge gradually the eccentric fixation
Case should be reviewed at monthly intervals for reassessment with the visuoscope.
Treatment must be cond until EF is completely disrupted.

109. • May take a period of as long as 1-3 months or more
• Initial result may be aimless, wandering loss of fixation with the visuoscope
• Failure to disrupt eccentric fixation by occlusion will prevent the redevelopment
of a good visual acuity.
• After achieving wandering/central fixation,conventonal occlusion is cond until
maximum VA is obtained.

110. 2. Red filter treatment
Advocated by Brinker and Katz, on basis of stimulating the cones of fovea
compared to those of the eccentric point, which has less cones.
Red filter was used over the amblyopic eye Eg-Kodak gelatin wratten filter
no.92,which excludes rays of wavelength shorter than 640 nm.
The dominant eye is given an opaque patch(occlusion).
The eccentric fixation may change.

111. 3. CAM Vision Stimulation
From Campbell and workers
Amblyopic eye is stimulated by slowly rotating high contrast square wave gratings
of different frequencies for seven minutes
The dominant eye is patched for the period of this treatment
It is useful as an adjunct to occlusion and impresses the px as he/she is doing
some exercise.

112. 4. Pleoptics Therapy
• Pleos=full,optikos=sight
• Aim is to actively stimulate macula in dense amblyopia with eccentric fixation
• Two methods, either Bangerter or Cupper

113. Bangerter’s Method:
Bangerter dazzled the extramacular retina including the eccentric point by bright light
protecting the macula by a disc projected onto it.
It was followed by intermittent stimulation of macula with flashes of light.
Performed by modified Gullstrand’s Ophthalmoscope,called as Pleoptophore.
The therapy was continued till the central scotoma weakens and the fixation becomes
central.

114. Cupper’s Method:
Use of After image which was created arould the center of fovea to give a new sense of
direction to the fovea which had lost its straight ahead gaze
Cupper used Euthyscope which had discs of varying sizes to create a central after image
apart from dazzling the eccentric point
He used the alternate flashing of room illumination(Alternascope) to perpetuate the
after images(forming negative after image in light and positive after image in dark)
Visuoscope to know the type of eccentric fixation

115. After image was projected on the wall or space coordinator where the hand eye
coordination was relearned
It was followed by exercises with Haidinger’s brushes on cupper’s coordinator. It uses
the property of fovea to polarise the light which was not possible by the eccentric
point.

116. REFERENCES:
Binocular Vision & Ocular Motility; Gunter K. Von Noorden
Theory and practice of Squint & Orthoptics; A.K Khurana
Management of strabismus & Amblyopia ; John A. pratt-Johnson
Clinical Management of Strabismus ; Elizabeth E. Caloroso
Previous Presentations
Internet