current trend in management of amblyopia · 2020. 5. 26. · amblyopia originated from greek word:...
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Current Trend in
Management of Amblyopia
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AMBLYOPIA
Old Definition: Reduction in visual form perception without anystructural deficits of the visual system, not correctable by opticalmeans
Current Definition: A unilateral or bilateral decrease of visualacuity caused by pattern vision deprivation or abnormal binocularinteraction for which no obvious causes can be detected by physicalexamination of the eye and cannot be corrected by optical orsurgical means but in appropriate cases is reversible by therapeuticmeasures
▪ Difference of > 2 lines between two eyes
▪ < 6/9VA
▪ Amblyopia originated from Greek word:
Amblyos - dullness / blunt, Ops – vision
▪ Condition in which the observer sees nothing & patient very
little
Prevalence
o Globally 1-5% (WHO 2015)
o In Nepal around 0.9 to 1.8%
o 4 times more frequent in premature children
o 6 times more frequent in children with delayed mile stones
o Smoking and use of drugs and alcohol during pregnancy have
been associated with risk of amblyopia
CLASSIFICATION OF AMBLYOPIA
Prognostic Factors in Amblyopia
Positive factor Negative factor
functional organic
Central fixation Eccentric fixation
Random dot stereopsis No random dot stereopsis
Short duration Long duration
Young patient, motivated Older patient, un-motivated
Type Prognosis Treatment
Organic
Tobacco
Toxic
Congenital
Good
Poor–fair
Poor
Abstinence
Medical attention
Functional vision therapy
Functional
Hysterical
Light deprivation
Refractive
Strabismic
Good
Poor
Good
Good
Psychotherapy
Remove obstacles
Refractive correction
Functional vision therapy
CURRENT TREND OF
MANAGEMENT
IMPORTANCE OF TREATMENT
▪ If left untreated, amblyopia produces a range of functional
deficits
▪ Binocular function is also compromised
▪ The presence of amblyopia (or its treatment) impact on
educational attainment, future career opportunities, self-esteem
& quality of life
▪ The studies reveal the practical and emotional impact of
amblyopia and provide additional evidence in support of the
need to develop effective treatment
Goal of Treatment
To restore and improve visual acuity by two strategies:
I. Present clear retinal image to the amblyopic eye
o Eliminate causes of visual deprivation
o Correcting visually significant refractive errors
II. Make the child use the amblyopic eye
▪ Recommended treatment should be based on
o Pt.’s age, VA, compliance with previous treatment &
physical, social and psychological status
What would be the perfect amblyopia
therapy?
▪ Effective
▪ Good compliance
▪ Acceptable to pts. and parent
▪ Quick
▪ Safe
▪ Easy to administer
▪ Cost effective
▪ Well maintained
Choices of Treatment
The choices of treatment of amblyopia are used alone
or in combination to achieve goal of treatment
1. Passive Therapy
The patient experiences a change in visual stimulation
without any conscious effort
i. Proper refractive correction
ii. Occlusion
iii. Penalization
2. 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
i. Pleoptics
ii. Near activities
iii. Active stimulation therapy using CAM vision stimulator
iv. Syntonic phototherapy
v. Role of perceptual learning
vi. Binocular stimulation
vii. Software-based active treatments
viii. Exposure to dark
ix. Pharmacological Therapy
Passive Therapy
Refractive Correction
OcclusionPenalization
Proper Refractive Correction
Purpose
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)
When to Prescribe
REFRACTIVE ERROR CORRECTION
Improves VA in 25-33% of patients with anisometropic amblyopia
and also in strabismic amblyopia
ATS-5 (PEDIG) 2006 concluded that amblyopia improved with
optical correction in 77% and resolved in 27%
Chen et al (AJO 2007) concluded that amblyopia improved with
optical correction in 93% and resolved in 45%
Penalisation and occlusion is required only if the VA doesn’t
improve with glasses for 4 months
Occlusion Therapy
▪ The most powerful and effective means of treating amblyopia
▪ Mainstay of treatment since 18th century to till now
▪ Highly effective until 8 years of age
▪ New studies have shown improvements upto 24 yrs of age
▪ Cover good eye to stimulate amblyopic eye
▪ Success rate 30-92%
o When fixation is central: simple & effective
o When fixation is eccentric: <7yrs central fixation recover
o Older the child harder to regain central fixation
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)
TYPES OF OCCLUSION
Occlusion
Total or Partial
Conventional or Inverse
Full Time or Part Time
Total VS Partial Occlusion
Total Partial
•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
Conventional VS Inverse
Conventional Inverse
•Occlusion of sound eye •Occlusion of amblyopic
eye so that eccentric
fixation becomes less fixed
Full Time VS Part Time
Full time Part time
Removed only while going to
bed at night
Short time each day during close
work or watching television
Choice of initial Rx In relapses after Rx and also for
maintenance
PatchesMicropore tape with soft tissue paper
Spectacle patch / frost glassDoyne’s occluder Opaque Contact Lens
How to go about Occlusion?
Motivation of child and parents
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 months
If there is no improvement, then treatment is stopped
Maintenance treatment is continued at least up to 9 yrs of
age with part time occlusion and exercises
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
Disadvantages of occlusion
Prolonged treatment
Occlusion amblyopia
Non compliance
Psychological distress
Allergic skin rash
Cosmetically inacceptable
Prognostic considerations
Younger the age better the prognosis
Type of amblyopia myopic anisometropia> hyperopic
anisometropia> strabismic amblyopia> stimulus
deprivation
Pre-treatment VA
Type of occlusion
Type of fixation
Near exercises
▪ Pt. compliance and parent education
▪ Presence of astigmatism
▪ Previous treatment
▪ Refractive correction
Treatment of Anisometropic Amblyopia
Treatment of Strabismic Amblyopia
Penalization
Therapeutic technique performed by optically defocusing the
eye with better vision by using cycloplegia or altering the eye
glass lens
Indications
o No compliance for occlusion
o Mild degrees of amblyopia
o Maintainence after occlusion
o Anisometropic amblyopia
Advantages: Cheap, better compliance
Disadvantages: Side effects of drugs
- Risk of occlusion amblyopia
- Systemic absorption
Unless penalisation decreases the VA of dominant eye below
the amblyopic eye this form of treatment is not adviced
Methods of penalisation
a. Near penalization: fixing eye is atropinized & fully
corrected for distance, amblyopic eye is overcorrected with
+2.00 to +3.00 D
b. Distance penalization: fixing eye is atropinized &
overcorrected, amblyopic eye is fully corrected
c. Total: fixing eye is atropinized & undercorrected by 4.00 to
5.00 D, amblyopic eye is fully corrected
Summary of the PEDIG studies
Short
title
Ages
(Yrs)
Baselin
e
amblyo
pic eye
acuity
Primary
outcome
measure
Initial
treatment
prescribed
Results
(Impro
vemen
t)
Primary conclusion
ATS 1
(35)
3 to
<7
20/40-
20/100
Lines
improvemen
t after 26
weeks
Daily
atropine
At least 6
hrs daily
patching
2.8 lines
3.2 lines
Atropine and patching are
equally effective as
primary treatment for
moderate amblyopia
ATS
2A
(37)
3 to
<7
20/100-
20/400
Lines
improvemen
t after 17
weeks
6 hrs daily
patching
Full time
patching
4.8 lines
4.7 lines
6 hrs daily patching
produces improvement
similar to full time
patching for severe
amblyopia
ATS
2B
(36)
3 to
<7
20/40-
20/80
Lines
improvemen
t after 17
weeks
2 hrs daily
patching
6 hrs daily
patching
2.4 lines
2.4 lines
2 or 6 hrs of prescribed
daily patching produce
similar improvement for
moderate amblyopia
Summary of the PEDIG studiesShort
title
Ages
(Yrs)
Baseline
amblyo
pic eye
acuity
Primary
outcome
measure
Initial
treatment
prescribed
Results
(Improvement)
Primary conclusion
ATS3
(39)
7 to
<18
20/40-
20/400
Proportion
of
responders
(improveme
nt >2 lines)
after 24
weeks
2-6 hrs daily
patching (+
atropine if <12
yrs)
Spectacles
alone if
needed
Response rates:
Age≤12 yrs:
53%
Age≥13 yrs:
25%
Age≤12yrs: 25%
Age≥13 yrs:
23%
ATS 4
(34)
3 to
<7
20/40-
20/80
Lines
improveme
nt after 17
weeks
Weekend
atropine
Daily atropine
2.3 lines
2.3 lines
Weekend and daily atropine
produce similar
improvement for moderate
amblyopia
ATS 5
(38)
3 to
<8
20/40-
20/400
Lines
improveme
nt after 5
weeks
2 hrs daily
patching
Spectacles
alone if
needed
1.1 lines
0.5 lines
After a period of spectacle
wear, 2 hrs daily patching is
superior to continuing
spectacles alone
Practical Implications of the PEDIG studies
Children < 7 yrs and VA between 6/12 to 6/24
- 2 hrs and 6 hrs patching - same effect
Children < 7 yrs and VA 6/30 - 6/120
- 6 hrs and full time patching - same effect
Children < 7 yrs and VA 6/12 - 6/30
- Daily atropine produces similar effect as 6 hrs patching
Practical Implications of the PEDIG studies
Children 7 to 18 yrs and VA 6/12 to 6/120
- 2 - 6 hrs patching leads to at least 2 lines improvement
(if no previous treatment) but
- the compliance rate is poor in age >13 yrs
Children < 8 yrs and VA 6/12 - 6/120
- Patching 2 hrs is better than spectacles alone
ACTIVE THERAPY
Pleoptics
▪ Pleoptics: Gr. meaning full vision
▪ Used for active stimulation of the fovea to overcome eccentric
fixation and improves the visual acuity
In this technique
- the peripheral retina is dazzled with an intense light protecting
foveal area
- after the light source is turned off, the fovea functions better
as the surrounding retinal area is in a state of hypofunction
- this can be followed by direct stimulation of fovea
by pleoptophore (Bangerter’s method)
or indirectly by producing after image (Cupper’s method)
Demerits
▪ The technique is complex and requires an absolute co-operation of the pt. and intelligence to appreciate after-images
▪ Daily sitting for a longer period of time is required
▪ Since occlusion of the dominant eye is a very successful simple and inexpensive method of treating eccentric fixation, so the use of pleoptics methods is abandoned
▪ Only indication is co-operative and intelligent child older than 6yrs having eccentric fixation
Pleoptics VS Occlusion of sound eye
▪ Visual acuity outcomes in children who have had conventional
occlusion are found to be better than in those who have gone
through pleoptic treatment (Verlee DL, Iacobucci 1967)
▪ Visual acuity improvements are significantly greater in the
direct occlusion group than in the group undergoing pleoptic
therapy and inverse occlusion (VeronneauT.S. et al 1974)
Treatment using grating stimuli
(Active stimulation therapy using
CAM vision stimulator)
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
o The sound eye remains open between the weekly treatment sessions
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 parents who can carry
out the treatment at home
▪ 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
▪ The stimulus is a drifting sinusoidal grating of a spatial frequency of
0.3 cyc/deg and a temporal frequency of 1 cyc/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
Syntonic phototherapy in the
treatment of amblyopia
▪ 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
▪ 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.
Role of perceptual learning in
amblyopia treatment
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
▪ 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
Video Game Play & Brain Plasticity
▪ The intense sensory-motor interactions are immersed in
video-game play
▪ This might push brain functions to the limit
▪ Enables the amblyopic visual system to learn, on the fly, to
recalibrate and adjust, providing the basis for functional
plasticity
Video Game Play & Brain Plasticity
▪ Game playing requires the allocation of spatial attention,
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
Video-Game Play Induces Plasticity in the
Visual System of Adults with Amblyopia(Roger W. Li1 et al, August 30 2011)
o 10 amblyopic adults: Action Video Game, 40 hrs, 2hrs/day
o 3 amblyopic adult: Non-action Video Game, 40 hrs, 2 hrs/ day
o Non-amblyopic eye: Occlusion
o Control Group 7 adults: Only patching
Action Game: Medal of Honor: Pacific Assault Non-Action Game: SimCity Societies
▪ PL is an area with clear potential for treating amblyopia
▪ Significant improvements in vision can result from training periods
that are relatively short using tasks that are relatively engaging,
compared to conventional occlusion
▪ It is important to be aware that the way in which these
improvements arise is not yet fully understood
▪ Further research is needed before optimal training strategies can
be devised and before the way in which those strategies modify
visual function can be fully understood
Binocular stimulation in the
treatment of amblyopia
▪ 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
▪ 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)
▪ 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
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
The ‘monocular fixation in a binocular field’ (MFBF)
technique
▪ 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 red
pen and wearing red-green glasses, with the red lens in front
of the non-amblyopic eye (Wick B. et al 1992)
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 Technologyo Shutter glasses
o High definition screens
o Faster processing speeds
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
DVD Player
o Border with controls common
to both eyes
o Only amblyopic eye sees the
DVD
NUX Game
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)
Fig: Visual acuity in LogMAR units for all patients from
baseline to week 10.
Herbison et al Eye 2013
Software-based active treatments
for amblyopia for use at home or in
office
The AmbP 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 day, 5
days per week
▪ Involve activities like ‘letter jump’, among others
▪ The treatment involves visual search of certain target types
The AmbP iNet program for the treatment of
Amblyopia
▪ Treatment system is designed to improve hand eye co-
ordination, 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 a part
of a treatment for amblyopia
▪ Thus, controlled trials of this treatment are needed
(Cooper J. et al 2007)
Not a "lazy" eye, but a "lazy" brain
Amblyopia therapy is:
o Completed at home on a computer
o 2-3 times per week
o Each of the 40 sessions takes an average of 40 minutes
▪ Precise visual tasks consisting of patterned images with subtle
differences in orientation, size and contrast
▪ Through repetitive practice the brain is trained to be more
efficient and to improve visual processing
▪ Specialized RevitalVision™ algorithms analyze performance
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
Fig: Visual Acuity (VA) in Amblyopic Eyes From Baseline to 16Weeks
(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 patching
• 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
Fig: Dig Rush Game
(K.R. Kelly et al 2016)
Fig: Best-Corrected Visual Acuity (BCVA) at Baseline, the 2-Week Visit, and the 4-Week Visit
(K.R. Kelly et al 2016)
▪ Binocular iPad game is a successful treatment for childhood amblyopia and is more effective than patching at the 2-week visit
Exposure to Darkness
Dark exposure promotes recovery from amblyopia
It is based on Duffy and Mitchell (2013, current biology) animal
(kittens) experiments
▪ Three key parameters will have to be established first
o What is the minimum period of dark exposure needed to trigger restoration of visual cortex plasticity?
o What is the age dependence of this effect?
o How absolute does the darkness have to be?
▪ The answers to these questions will ultimately determine the utility of this approach to treating amblyopia
Pharmacological Therapy
▪ Levodopa & citicoline are the most extensively studied drugs
▪ Plasticity of visual system during the sensitive period is dependent
on input from non-adrenergic neurons and thus can be subjected
to pharmacological manipulation
▪ Precursor for the catecholamine dopamine, a neurotransmitter,
known to influence visual system at retina and cortical level
▪ It either extends or reactivates the visual system’s sensitive
period of neural plasticity
▪ Catecholamine based medical treatment has been demonstrated
to improve vision in amblyopic eyes.
▪ Leguire and co-workers (1993) found that 1 hr after levodopa
ingestion,VA, CS and PVEP temporarily improve but starts to
decrease 5 hrs after drug ingestion
▪ They concluded that combination of levodopa and occlusion
improves visual function more than levodopa-carbidopa alone
in amblyopic children
▪ Dadeya et al (2009) concluded that there is more than two
lines improvement in visual acuity, especially in children
younger than eight years of age
▪ Citicoline (cytidine 5’-diphosphocholine) used in a dose of
1,000 mg I.M. for 15 days to patients aged 9–37 yrs causes a
temporary improvement in visual acuity without any side
effects (Campos et al 1995)
▪ Use of oral levodopa while continuing to patch 2 hrs daily
does not produce a clinically or statistically meaningful
improvement in VA compared with patching (PEDIG 2015)
Advantages
o Augments conventional occlusion
o Speeds up recovery of visual functions
o Improves compliance
o Possibility for adult amblyopes
o Reduces cost and duration of treatment
Near activities used in the
treatment of amblyopia
▪ 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
Summary
▪ Amblyopia occurs due to abnormal visual experience early in life
▪ Proper optical correction alone is necessary for short period of
time (6-8 weeks) before initiation of other therapy
▪ Part time occlusion of better eye is mainstay of treatment since
18th century to till now
▪ For severe and moderate amblyopia, 6 hrs and 2 hrs of patching
is advised respectively
▪ Atropine is also used in children with poor compliance
▪ Trial of patching can be given in patients as old as 17 yrs of age
▪ Perceptual learning and pharmacological manipulation have
shown areas of amblyopia treatment beyond the critical period
of visual development
▪ Binocular stimulation, software based treatments and other
methods do not have promising result to replace the patching
therapy till date
▪ Most of the active therapy methods have good results when
used together with patching therapy
Summary
Amblyopia is still an unsolved problem, the best
modality of treatment is still to be explored in future
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