Management of Amblyopia.pptx

useful for undergrad students

1. MANAGEMENT OF AMBLYOPIA ANUJA DHAKAL BOVS 3 RD YEAR

2. layout INTRODUCTION OF AMBLYOPIA ETILOGY AND CLASSIFICATION OF AMBLYOPIA MANAGEMENT OF AMBLYOPIA CONVENTIONAL PASSIVE THERAPIES ACTIVE VISION THERAPY BINOCULAR THERAPIES RECENT ADVANCES IN MANAGEMENT OF AMBLYOPIA SUMMARY CONCLUSIONS 2

3. INTRODUCTION Amblyopia comes from the Greek word meaning dull sight or blunt sight. Amblyopia occurs to abnormal visual experience early in life . Amblyopia can be defined in numerous ways, but comprises a reduction in visual function of one or both eyes, which is not attributable to any clinically apparent lesion and is not immediately eliminated following the optical correction of a refractive error. 3

4. Von Noorden has clinically defined amblyopia as unilateral or bilateral reduction in best-corrected visual acuity caused by form vision deprivation and/or abnormal binocular interaction, without a visible organic cause commensurate with this visual loss. This significant reduction in corrected central visual acuity is labelled to visual acuity less than 6/12 in bilateral amblyopia and a difference of two or more lines between normal and abnormal eye in unilateral amblyopia   4

5. DESCRIPTION OF EVIDENCE Literature searches limited to English language studies and with no date restrictions were conducted in January 2018 in the PubMed database and updated in April 2019, and in the Cochrane Library database with no restrictions. The following terms were used, along with publication and language filters: Amblyopia[ mh ], amblyop *, “lazy eye,” “lazy eyes,” amblyopia, amblyopic, strabismic , anisometropic , binocular, dichoptic. Therapy, therapies, treat, treatment, train, training, “amblyopia prevention and control ” OR “video games”[ mh ],”Oculus rift,” ipad , i -bit, plasticity, “computers, handheld”[ mh ], BRAVO, “video clips,” “interactive games,” “perceptual learning,” “amblyopia/therapy”[ mh ]. 5

6. BACKGROUND Amblyopia is the most common cause of monocular vision loss and occurs in 2% to 4% of children . In Nepal, there is no population based study on the prevalence of amblyopia. However there are few studies on school children which shows the prevalence of amblyopia to be 0.9 to 1.8 %. Nepal BP, Koirala S, Adhikary S, et al. Ocular morbidity in school children in Kathmandu . Br J Ophthalmol 2003;87:531-4 . Sapkota YD , Adhikari BN , Pokharel GP, et al. The prevalence of visual impairment in school children of upper-middle socioeconomic status in Kathmandu. Ophthalmic Epidemiol 2008;15:17-23 . 6 https://doi.org/10.1016/j.ophtha.2019.08.024 @2019 by the American Academy of Ophthalmology Published by Elsevier Inc

7. 7

8. AMBLYOGENIC FACTORS: 1)REFRACTIVE 2) STRABISMIC 3)FORM DEPRIVATION 4)TOXIC 8

9. 1)REFRACTIVE Isometropia Anisometropia Astigmatism >2.50D > 1.50D Hyperopia >5.00D > 1.00D Myopia > 8.00D > 3.00D 9 http://www.aoa.org/

10. 2) STRABISMIC Misalignment of the eyes results in suppression of input from one eye in order to avoid visual confusion. Criteria:■ Constant (or mostly constant ) ■ Unilateral (or mostly unilateral ) ■ Distance and Near ■ Direction ( eso vs exo ) ■ Onset before the critical period 10

11. MORE IN ESOTROPIA THAN EXOTROPIAS # NAS0-TRMPORAL ASYMMETRY OF RETINOCORTICAL PROJECTION. #AMBLYOPIA OF USE AND MISUSE 11

12. 3)FORM DEPRIVATION Examples : ■ Congenital or Traumatic Cataract ■ Early complete ptosis ■ Corneal Opacity ■ Vitreous Hemorrhage ■ S/P TARSORRAPHY IN CHILDHOOD ULCERS 12

13. 4)TOXIC a)TOBACCO :DEGENERATION OF PAPILLOMACULAR BUNDLE b)ETHYL ALCOHOL:DEGENERATION OF GANGLION CELLS c)METHYL ALCOHOL:OPTIC ATROPHY d) QUININE:RX OF MALARIA DISC PALLOR e) ETHAMBUTOL:ANTI-TUBERCULAR MIMICS PAPILLITIS 13

14. TYPES OF AMBLYOPIA 14

15. ORGANIC AMBLYOPIA ■CONGENITAL ■TOXIC ■NUTRITIONAL 15 FUNCTIONAL AMBLYOPIA

16. ANISOMETROPIC AMBLYOPIA: ISOMETROPIC AMBLYOPIA MERIDIONAL AMBLYOPIA STRABISMIC AMBLYOPIA STIMULUS DEPRIVATION TYPE REVERSE AMBLYOPIA 16

17. REVERSE AMBLYOPIA: Iatrogenic interference with vision in childhood (therapeutic occlusion or cycloplegia ) . In the treatment of unilateral amblyopia, the initially amblyopic eye usually seems to achieve normal vision in the process, but occasionally bilateral amblyopia may result . Severe amblyopia has been reported after as little as 1 week of unilateral patching in children under 2 years of age following minor eyelid surgery 17 Simons K. Amblyopia characterization, treatment, and prophylaxis. Surv Ophthalmol 2005;50:123-66. Levi DM , Klein S. Hyperacuity and amblyopia. Nature 1982;298:268-70.

18. AMBLYOPIA FINDINGS ■ Amblyopia is more than simply reduced visual acuity : – Grating acuity better than snellen’s chart,better on peripheral zone of acuity charts – Decreased stereopsis – Affected by crowding phenomenon – Strabismus (may be secondary to poor vision/ microtropia ) – H yperacuity also reduced In vernier charts 18

19. AMBLYOPIA FINDINGS ■ Additional Findings : – Poor eye tracking – Reduced contrast sensitivity – Abnormal spatial distortions – Normal peripheral vision – Central scotoma under binocular viewing conditions from amblyopic eye. – Accomodation lag –Neutral filter changes va in organic cause 19

20. DIAGNOSIS OF AMBLYOPIA KEY POINTS 1) Amblyopia is a diagnosis of inclusion and exclusion 2) Diagnosis must make sense in severity 3) Response to treatment is part of the diagnosis 20

21. INCLUSION V/S EXCLUSION 21 EXCLUSION: INCLUSION: • rule out ocular pathology as a cause of decreased vision by at least performing thorough anterior and posterior ocular health Exclusion: assessment with DFE • must be able to document a specific etiology for the amblyopia such as • Amblyogenic refractive error • Amblyogenic strabismus • Amblyogenic form deprivation

22. SEVERITY ■ Anisometropic and Strabismic – Typical acuity loss: 20/30- 20/100 – Refractive amblyopia should make sense in severity ■ Form deprivation can be worse ■ Long standing strabismic amblyopia can be worse 22

23. TYPES OF AMBLYOPIA ACCORDING TO SEVERITY Mild to Moderate : visual acuity in the amblyopic eye between 20/80 or better Severe : visual acuity in the amblyopic eye between 20/100 and 20/400 23 American Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern Guidelines

24. RESPONSE TO TREATMENT Should get better as treatment begins •Understand prognosis If no improvement… • Incorrect diagnosis • Wrong prescription • Compliance 24

25. MANAGEMENT OF AMBLYOPIA 1)PREVENTION 2)CHOICE OF THERAPY 3)RECENT ADVANCES IN TREATMENT OF AMBLYOPIA 25

26. PREVENTION Vision screening is important to identify factors that predispose to amblyopia . When amblyopia is present,it appears that the potential for successful treatment is greatest in young children, although improvement in visual acuity can reasonably be expected in older children and teenagers. 26

27. A study by Pediatric Eye Disease Investigator Group of treatment of moderate strabismic and/or anisometropic amblyopia demonstrated that the visual acuity of the amblyopic eye improved to 20/30 or better 6 months after initiating treatment in approximately three‑quarters of children under 7 years of age. 27 Glaser SR, Matazinski AM, Sclar DM , Sala NA, Vroman CM, Tanner CE, et al. A randomized trial of atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol 2002;120:268‑78.

28. TREATMENT MODALITIES 1)PASSIVE THERAPY OPTICAL CORRECTION OCCLUSION/PATCHING PENALISATION 28

29. OPTICAL CORRECTION Eliminating optical blur and providing an optimal environment for amblyopia therapy is essential – Anisometropia ■ The anisometropic difference between the two eyes MUST always be maintained in the glasses – Astigmatism ■ The FULL amount needs to be corrected 29

30. – Hyperopia ■ If/when reduced for children without strabismus , done symmetrically – Hyperopia with Esotropia ■ Full amount of hyperopia or undercorrecting by +0.50D based on cycloplegic refraction – Myopia ■ The full amount is corrected Based on PEDIG protocol 30

31. 31

32. Amblyopia Treatment Study 5 ( ATS 5) Ophthalmology 2006; 113: 895-903 Evaluating optical correction alone in anisometropic amblyopes – 84 children ages 3- <7 yo with VAs : 20/40- 20/250 ■ VA improved with glasses by >/= 2 lines in 77% ■ Amblyopia resolved* completely in 27% with glasses alone ■ Average improvement was 3 lines 32

33. ATS 7 AM J Ophthalmol 2007; 144: 487- 496 ATS7: Optical correction for bilateral refractive amblyopia ■ 113 children, 3- <10 y.o with VA 20/40- 20/400 ■ Hyperopia: >/= 4.0D, Astigmatism: >/= 2.0D ■ Glasses alone improved VA to 20/25 or better within 1 year 33

34. ATS 13 Ophthalmology 2012; 119: 150-158 Optical correction for strabismic amblyopia or combined mechanism amblyopia ■ 146 children, 3 - <7 yo ■ 75% >/= 2 line, 54% >/= 3 lines ■ Resolution of amblyopia in 32% ■ Greater improvement in strabismic amblyopia alone (3.2 vs 2.3 lines 34

35. 35 OCCLUSION/PATCHING

36. The improvement in visual acuity with patching is likely related to the associated decrease in neural signals from the fellow or nonamblyopic eye, as demonstrated by recordings from the visual cortex in experimental animals . 36

37. “ GENERAL OCCLUSION ”REFERS TO PATCHING WITHOUT SPECIFIC PLANNED ACTIVITIES. “ THERAPY OCCLUSION ”REFERS TO PATCHING THAT IS COMBINED WITH SPECIFIC PLANNED ACTIVITIES. 37

38. GOALS OF PATCHING DIFFERENTIAL DIANGNOSIS (MONOCULAR V/S BINOCULAR IMPROVEMENT OF AMBLYOPIA ELIMINATION OF SUPPRESSION AWARENESS OR ELIMINATION OF DIPLOPIA DISRUPTION OF ANOMALOUS CORRESPONDANCE 38

39. FIELD COVERAGE OCCLUDERS PARTIAL FULL FIELD HALF PATCH DISTANCE OR NEAR FIELD SECTOR PATCHES SELECTED GAZES BINASALS NASAL FIELD(TEMPORAL RETINA) BITEMPORAL TEMPORAL FIELDS(NASAL RETINA) 39

40. TYPES OF OCCLUDERS 1)BANDAGE OCCLUDERS 2)SPECTACLE TAPES 3)TIE ON OCCLUDERS 4)CLIP ON OCLLUDERS 5)OCCLUSION LENSES 6)OCCLUSION FILTERS 40

41. EXCLUSION FOR PATCHING: CONSTANT EXOTROPES WHO CHANGE QUICKLY INTO INTERMITTENT STRABISMUS WITH THERAPY. INFANTS AND TODDLERS DUE TO DEVELOPING NEURAL PLASTICITY UPTO AGE OF APPROXIMATELY 2 YEARS assaf 1982:von noorden 1981 41

42. TIME PLANS FOR PATCHING 1)CONTINUAL WEAR: 2)FULL TIME WEAR: 3)PART TIME WEAR: 42

43. DIRECT OCCLUSION HABITUAL VISUAL STIMULATION IS ALTERED, AND THE NON PREFERRED EYE RECEIVES NEW SENSORIMOTOR STIMULATION. RECOMMENDED WHEN THERE IS FOVEAL OR UNSTEADY ECCENTRIC FIXATION IN THE AMBLYOPIC EYE. 43

44. INVERSE OCCLUSION COMBINED INVERSE AND DIRECT PATCHING PLAN IS TO PRESCRIBE INVERSE OCCLUSION DURING WORKING OR SCHOOL HOURS AND DIRECT OCCLUSION AFTER WORK . RESULTS ARE SLOWER AND SOMETIME EVEN INEFFECTIVE. 44

45. ALTERNATE OCCLUSION IN CASES OF ALTERNATE STRABISMUS(CONSTANT),FULL TIME OCCLUSION ALTERNATED DAILY BETWEEN TWO EYES. PURPOSE OF FULL TIME OCCLUSION FOR STRABISMUS WITH NO AMBLYOPIA IS TO DISRUPT THE SENSORY ANOMALIES. 45

46. ATS 2A Ophthalmology 2003; 110: 2075-87 6h/day vs Full time patching ■ 175 children 3 to <7yo with severe amblyopia (20/100-20/400 ) ■ Either 6 vs full time patching (all hours or all but 1 hour) with 1 hour near work included during patching ■ Amblyopia secondary to strabismus, anisometropia or both ■ Conclusion: Measured VA after 4 months: improvement of VA was of similar magnitude (4.7 lines) in both groups 46

47. ATS 2B Arch Ophthalmol 2003; 121: 603-611 2 vs 6h/day patching ■ 189 children 3- <7yo with moderate (20/40 - 20/80) amblyopia ■ Either 2 vs 6 h/day patching with 1 hour near work included during patching ■ Amblyopia secondary to strabismus, anisometropia or both ■ Conclusion: Measured VA after 4 months : improvement of VA was of similar magnitude (2.4 lines) in both groups 47

48. ATS 1 Arch ophthalmol 2002; 120: 268-278 Atropine vs Patching for Moderate Amblyopia ■ 419 children, <7yo with moderate amblyopia ■ Either 6 h/day (or more) patching (n= 215) or 1gtt 1% Atropine daily ( n=204 ) ■ 6 month outcome : improvement in VA was of similar magnitude from both therapies , although improvements from patching were more rapid 48

49. REALITIES OF OCCLUSION THERAPY *Disruptive to the homeostasis of the patient *Emotionally disruptive *Visual spatial disruptive *Disruptive to gross motor and bilateral integration in early child development *Disruptive to binocular vision development 49

50. RISK FACTORS ASSOCIATED WITH PATCHING * Psycho-social Bullying , teasing *Emotional Frustration Anger General unhappiness *Danger in playing sports, crossing streets, riding bicycle, operating motorized vehicles or machinery *Difficulty functioning in classroom or other activities in daily living 50

51. COMMON PITFALLS TO OCCLUSION THERAPY * Acuity improves but will often regress when patching is discontinued. *Patient typically maintains binocular suppression. *Patient often remains “stereo-blind” 51

52. RECENT ADVANCES IN OCCLUSION Liquid Crystal Display Eyeglasses Intermittent occlusion therapy Amblyz liquid crystal intermittent occlusion glasses ( XPAND 3D Group, Ljubljana, Slovenia ). The eyeglasses alternate between a clear and opaque lens before the fellow eye. 52

53. Programmed to unilaterally alternate between opaque and transparent phases at 30-second intervals, providing effective occlusion of the fellow eye 50% of the time they are worn. 53

54. PENALIZATION THERAPY In the past, penalization therapy was reserved for children who would not wear a patch or in whom compliance was an issue . Atropine 1%, a cholinergic antagonist, is instilled into the non-amblyopic eye and causes pupillary dilation and reduced accommodation subsequently forcing the amblyopic eye to be used for near-vision tasks. 54

55. Historically, atropine penalization has been advocated for mild to moderate amblyopia with vision better than 20/100 because the blurring effect  was considered insufficient to improve vision in severely amblyopic eyes . However, a recent study has shown that atropine does improve amblyopia even in severely amblyopic eyes (20/125 – 20/400). 55 https://www.aao.org/disease-review/amblyopia-treatment-modalities

56. HOW IT WORKS? works best when the nonamblyopic eye is hyperopic. The cycloplegia optically defocuses the nonamblyopic eye, most often with atropine 1% solution . This technique may also be considered in the presence of latent nystagmus , occlusion failure, or for maintenance treatment. 56

57. PREREQUISITES FOR PENALIZATION : EYES SHOULD BE STRAIGHT 57

58. SOME DISADVANTAGES OF ATROPINE PENALIZATION : LONG TERM EFFECT SYSTEMIC SIDE EFFECTS FLUSHING DRY MOUTH HYPERACTIVITY SEIZURES TRACHYCARDIA ALLERGY 58

59. METHODS OF PENALIZATION Atropine penalization : Near Penalization – Normal eye is atropinized and fully corrected for distance vision, while amblyopic eye is overcorrected with +2 or +3 D. Distance Penalization – Normal eye is atropinized and overcorrected by 4 – 5 D, while amblyopic eye is fully corrected. Total penalization – Normal eye is atropinized and undercorrectedby 4-5D, while amblyopic eye is fully correcteed . 59

60. 2) Optical Penalization – Prescribing more plus to sound eye to force amblyopic eye to fix for distance targets. 60

61. Comparison of Patching to Atropine for Amblyopia Treatment Patching Atropine Dose Initially 2 hours daily One drop daily on weekends Reversibility Immediate Effect lasts 1-2 weeks Binocularity None Peripheral binocularity Compliance Poor Ensured compliance Complications Local irritation and allergy Rare but serious Results Equal to atropine if compliant Equal to patching but slower improvement in vision 61

62. CLINICAL IMPLICATIONS OF ATROPINE PENALIZATION DAILY ATROPINE ADMINISTRATION IS NOT NECESSARY ;A TWICE PER WEEK IS ALSO EFFECTIVE. THERE IS NO REASON TO BELIEVE THAT ATROPINE NEEDS TO BE ADMINISTERED ONLY ON WEEKEND DAYS OR THAT THE DAYS NEEDS TO BE SEQUENTIAL. WEEKEND ATROPINE PENALIZATION HAS SHOWN TO BE EEFECTIVE IN TREATING BOTH MODERATE AND SEVERE AMBLYOPIA 62

63. ATS 1 Arch ophthalmol 2002; 120: 268-278 Atropine vs Patching for Moderate Amblyopia ■ 419 children, <7yo with moderate amblyopia ■ Either 6 h/day (or more) patching (n= 215) or 1gtt 1% Atropine daily ■ 6 month outcome: improvement in VA was of similar magnitude from both therapies , although improvements from patching were more rapid 63

64. ATS 4 ophthalmology 2004; 111: 2076-85 Weekend vs Daily Atropine therapy ■ 168 children, 3- <7 yo with moderate amblyopia ■ Either daily atropine or weekend atropine for 4 months ■ 4 month outcome: Similar improvement in VA in both treatment groups (~2.3 lines) 64

65. ATS 6 Ophthalmology 2008; 115: 2071-78 Patching 2 hours with near vs distance activities ■ 425 children 3 - <7 yo with VA 20/40-20/400 ■ Amblyopia 2’ to anisometropia , strabismus or mixed ■ Either 2 hours/day patching with near activities or with distance activities ■ At 8 week outcome : similar improvement of VA in amblyopic eye in both groups: distance activity (2.6 lines) and near activity (2.5 lines) ■ Similar outcomes even at 2, 5, and 17 week visits. 65

66. 2)ACTIVE THERAPY Active Vision Therapy in Amblyopia is designed to improve visual performance by the conscious involvement in a sequence of a specific, controlled visual task that provide feedback. 66

67. Pleoptics Active stimulation therapy using CAM vision stimulator. Syntonic phototherapy Role of perceptual learning Binocular stimulation Software-based active treatments Exposure to dark Pharmacological Therapy 67

68. PLEOPTICS   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 . \ ( Bangerter’s method ) ( Cupper’s method) 68

69. Active stimulation therapy using CAM visionActive stimulation therapy using CAM vision Active stimulation therapy using CAM vision 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. 69

70. Principle ; Assumption that rotating grating provides specific stimulation for cortical neurons Present status of CAM vision stimulator. Advantages over occlusion therapy; The sound eye remains open between the weekly treatment sessions. 70

71. Syntonic phototherapy Syntonics is the branch of ocular science dealing with the application of selected visible light frequencies through the eyes f or 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. 71

72.   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 , there seems to be no basis for prescribing this treatment . 72 Wallace LB. The theory and practice of syntonic phototherapy 2009 Spitler HR. The Syntonic Principle. Pennsylvania: Science Press Printing Company, 1941.

73. Bin BINOCULAR THERAPIES ular stimulation 73

74. The depth of amblyopia has been positively correlated to the degree of binocular imbalance. Affected individuals show impaired stereoacuity and abnormal binocular summation. Binocular therapies designed to improve amblyopia through binocular stimulation are largely broken down into perceptual learning and dichoptic training. 74

75. 1)PERCEPTUAL LEARNING Any relatively permanent and consistent change in the perception of stimulus array following practice or experience with this array- Gibson (1963) 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. 75

76. A number of visual tasks have been explored as a means to apply perceptual learning, including vernier acuity, Gabor detection, positional discrimination, letter identification in noise, position discrimination in noise and contrast detection. It is noteworthy that monocular perceptual training has been shown to lead to an improvement in binocular vision. 76

77. Application of perceptual learning to various visual tasks has reportedly resulted in improvement in several measures, including visual acuity, orientation discrimination, reduction of the crowding phenomenon via repetition of task, stereoacuity , and contrast sensitivity. 77 6 Crist RE, Li W, Gilbert CD. Learning to see: experience and attention in primary visual cortex. Nat Neurosci 2001;4:519–25

78. Advocates of perceptual learning note that the specific nature of the stimuli chosen for training tasks contributes to the capacity for generalisability of the trained discrimination . DRAWBACKS : Most of the aforementioned studies contained very small numbers of participants, limiting generalisability to populations at large . Perceptual learning effects have been demonstrated to last hours to months without continued practice, but long-term follow-up is lacking. 78

79. 2)DICHOPTIC TRAINING Dichoptic training is a visual training process involving the presentation of different stimuli to each eye; in order to achieve the tasks, the summation of both stimuli is required. Dichoptic training relies on improving binocular visual function and thus addresses the suppression of the amblyopic eye, leading to a gradual overall improvement in visual function in terms of visual acuity and sensory function. 79

80. 1)DICHOPTIC TRAINING 80

81. 81

82. As the patient’s developing binocular function improves, the contrast difference between the two eyes is reduced, potentially to a point where no difference is required. VA gains follow improvements in binocularity and contrast sensitivity, presumably due to reduced suppression 82

83. 3)INTERACTIVE BINOCULAR TREATMENT PROJECT The Interactive Binocular Treatment (I- BiT ) project was set up to treat amblyopia with video games/video footage viewed with 3D viewing technology The I- BiT system allowed both eyes to receive an image but crucial parts of the image were seen only by the amblyopic eye. 83

84. 84

85. Treatment involved either playing computer games or watching short films with footage sent only the amblyopic eye within a border/background common to both eyes. Results from an early I- BiT prototype were promising; children who had no success with patching treatment demonstrated improvements in visual acuity with I- BiT (mean 0.250 LogMAR ; n=6) with a mean total treatment duration of just 4.4 hours and treatment was enjoyable for children. 85 Waddingham PE, Butler TK, Cobb SV , et al. Preliminary results from the use of the novel Interactive binocular treatment (I- BiT ) system, in the treatment of strabismic and anisometropic amblyopia. Eye ( Lond ). 2006;20:375–8

86. Advances in 3D viewing technology from the gaming industry allowed for a more user-friendly/mobile I- BiT system using shutter glasses. Shutter glasses turn off and on rapidly, alternating between right and left lens in sync with the ‘refresh’ rate of a computer monitor so that a different image can be sent to each eye. 86

87. 4)BALANCED BINOCULAR VIEWING THERAPY Bossi et al. have described a new approach to binocular treatment of amblyopia, which they have named ‘balanced binocular viewing therapy ’. This relies on watching 3D, dichoptic movies while wearing specially designed goggles, combined with an interactive game that aims to measure suppression. 87

88. 5)BINOCULAR TREATMENT OF AMBLYOPIA USING VIDEOGAMES CLINICAL TRIAL. (BRAVO) study 6) iPod BINOCULAR HOME-BASED TREATMENT. 88 (BRAVO) study

89. RECENT ADVANCES: Transcranial magnetic stimulation Transcranial magnetic stimulation (TMS) is an established , safe, and noninvasive technique for stimulating the human brain. The technique is based on the principle of electromagnetic induction, whereby a brief magnetic field is generated within a plastic-coated coil of wire that is placed on the head above the cortical area to be stimulated. 89

90. 90

91. The first study to assess the effect of repetitive TMS on visual function in adult with amblyopia demonstrated a transient improvement in contrast sensitivity. TMS is expected to enhance the effects of traditional amblyopia treatments.The effects of repeated applications of TMS as a therapeutic option in amblyopia are currently being investigated. 91 . Hess RF , Thompson B. New insights into amblyopia: binocular therapy and noninvasive brain stimulation. J AAPOS 2013;17:89-93

92. 92 Two clinical trials have demonstrated some benefit of acupuncture in the treatment of anisometropic amblyopia . Acupuncture for amblyopia requires further investigation . The effect of acupuncture on strabismic amblyopia has not been studied. The mechanism of action for acupuncture in the treatment of amblyopia is unknown. ACUPUNCTURE Lam DS, Zhao J, Chen LJ, et al. Adjunctive effect of acupuncture to refractive correction on anisometropic amblyopia: one-year results of a randomized crossover trial. Ophthalmology 2011;118(8):1501-11

93. PHARMACOLOGICAL THERAPIES The opportunity to neurosensitise a brain to allow for improvement with patching or atropine in children for whom conventional treatments have failed or after the critical period has ended is desirable. Pharmaceutical agents may offer that ability and a select few have reached human studies 93

94. 1)LEVODOPA- CARBIDOPA 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. 94

95. 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 95

96. 2) CITICOLINE 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). Treating adult amblyopes with CDP-choline has the effect of improving their VA, CS and VEPs. Changes occur in both eyes, although to different extents, and resemble those previously reported for levodopa treatment. 96 Porciatti , V., Schiavi , C., Benedetti, P., Baldi , A., & Campos, E. C. (1998). Cytidine-5'-diphosphocholine improves visual acuity, contrast sensitivity and visually-evoked potentials of amblyopic subjects.  Current eye research ,  17 (2), 141–148. https:// doi.org/10.1076/ceyr.17.2.141.5606

97. OTHER DRUGS ONGOING CLINICAL TRIALS Selective serotonin reuptake inhibitors ( SSRI ) treatment has been shown to augment visually‑evoked potentials ( VEPs ) in normal human subjects. In a few adult patients with amblyopia, SSRI (citalopram) enhanced visual acuity improvements when combined with two weeks of occlusion therapy, but effects in the population were not significantly different from placebo. 97

98. Stryker et al. in their paper mention an ongoing clinical study at Boston Children’s Hospital is using donepezil , a cholinesterase inhibitor that is typically used to treat Alzheimer’s disease, to boost cholinergic signaling, and recover vision in amblyopic patients is mentioned . 98

99. DRAWBACKS TO MEDICAL THERAPY A liquid suspension of levodopa is available to facilitate use in a young patient population, although has a reportedly unpleasant bitter taste . The addition of carbidopa to the prescribed formulation reduces these gastrointestinal side effects by inhibiting peripheral conversion of levodopa to dopamine. One worrisome result from the PEDIG study was regression of treatment effect with drug cessation 99

100. EXPOSURE TO DARK Dark exposure promotes recovery from amblyopia. It is based on Duffy and Mitchell (2013, current biology) animal (kittens) experiments. Three key parameters 1)What is the minimum period of dark exposure needed to trigger restoration of visual cortex plasticity? 2)What is the age dependence of this effect? 3)How absolute does the darkness have to be?  The answers to these questions will ultimately determine the utility of this approach to treating amblyopia. 100

101. SURGICAL MANAGEMENT For the strabismic amblyopia, strabismus surgery is performed according to the type of strabismus. Similarly , for the stimulation deprivation, pediatric cataract surgery, or the ptosis surgery should be done according to the aetiology of the stimulation deprivation. However , glasses should be used and patching should be done even after the surgery as per visual and refractive status of the patient 101

102. REFRACTIVE SURGERY PEDIG is currently planning Amblyopia Treatment Study 19, which is a controlled randomized clinical trial that will compare PRK versus nonsurgical treatment of anisometropic amblyopia in children who have failed conventional treatment . The results from this trial may provide yet more evidence for the use of refractive surgery in the management of amblyopia. 102

103. REFERENCES AMBLYOPIA PREFERRED PRACTICE PATTERN–AAO CYBERSIGHT.ORG PEDIG STUDY(2002-2016) GUNTHER K VON.NOORDEN EDITION AMERICAN OPTOMETRY ASSOCIATION – AOA BRITISH JOURNAL OF OPHTHALMOLOGY PUBMED RESEARCHGATE ARTICLES 103

104. THANK YOU 104 THANK YOU