Esotropia

basics, diagnosis and management of esotropia

1. ESOTROPIA - SHREYA

2. Esotropia Derived from 2 greek words- ‘ eso ’ which means ‘inward and ‘ trepo ’ means ‘turn’.

3. PSEUDOESOTROPIA Apparent convergent squint Angle kappa- negative Causes: 1. Telecanthus 2. Epicanthus

4. Symmetric corneal reflections Epicanthus - no strabismus

5. Asymmetric corneal reflex- Hirschberg’s test

6. (A)-Symmetric central Asymmetric – (B) - Pupillary margin: 15° (C) - Close to limbus : 30° (D) -Beyond limbus : 45°

7. Three commonly recognized stages: Esophoria Intermittent Esotropia Esotropia

8. ESOPHORIA

9. INTERMITTENT ESOTRORIA Esodeviation that is intermittently controlled by fusion mechanisms. Manifest under certain conditions such as fatigue, illness and stress.

10. ESOTROPIA Esodeviation that is not controlled by fusional mechanisms so that deviation is constant

11. Neurogenic Myogenic Musculofacial other Refractive Non refractive Essential infantile Essential acquired Acute comitant Microtropia Cyclic esotropia Sensory esotropia Nystagmus blockage syndrome

12. CONCOMITANT ESOTROPIA

13. ACCOMODATIVE ESOTROPIA Esodeviations due to excessive convergence associated with accomodation are called accomodative esotropia .

14. CLINICAL PRESENTATION MOST CONSISTENT FEATURE: VARIABLE ANGLE OF ESODEVIATION WHICH INCREASES WITH THE EFFORT FOR ACCOMODATION

15. REFRACTIVE NORMO-ACCOMODATIVE ESOTROPIA Uncorrected hyperopia To see clear at distance- they accommodate- esodeviation for distance fixation. Normal AC/A- therefore ET same for distance and near (within 15 PD) NO CONVERGENCE EXCESS Respond well to full cycloplegic correction of hyperopia

16. Usually mild to moderate hyperopia (+2 to +6D) Very high hyperopia - donot accommodate- bilateral amblyopia Apart from ET and amblyopia , they may present with asthenopia due to constant accomodative effort.

17. Case - 4yr/male 6/6 6/6

18. AC/A RATIO Heterophoria method AC/A= IPD+ (∆n- ∆d)/3 Normal- 5-7.5pd/1D Gradient method AC/A= N-D/3 Normal- 3-5pd/1D

19. REFRACTIVE HYPER-ACCOMODATIVE ESOTROPIA ET for distance + convergence excess (>15PD) ET for near (at 33cm) High AC/A ratio

20. NON REFRACTIVE ACCOMODATIVE ESOTROPIA No clinically significant hyperopia No accomodation for distance- no ET for distance High AC/A ratio >15PD ET for near ‘Hyper accomodative type’

21. HYPO-ACCOMODATIVE ESOTROPIA Weak accomodative mechanism Over- accomodation Normal AC/A ratio Convergence excess type Remote NPA and NPC- whereas hyper accomodative type have a normal NPA Seen in early presbyopes or cases under mild cycloplegia

22. AGE OF ONSET 2 nd year of life Variable angle of ET, presence of convergence excess and full cycloplegic error should be looked for.

23. MANAGEMENT Full cycloplegic correction If convergence excess- bifocals are prescribed. The minimal plus add that corrects convergence excess ET is added.

24. ESSENTIAL INFANTILE ESOTROPIA Early onset- high risk of amblyopia Large angle ET(30pd) Free alteration/ cross fixation in alternators and fixation preference of normal eye in amblyopes No significant refractive error No Neurologic deficit Confirmed only after 4-6 months

25. 7.May be associated with: IOOA (68%) Nystagmus (33%) DVD(50%) 8. Asymmetric optokinetic nystagmus : Temporal to nasal- smooth Nasal to temporal- cogwheel

26. A special characteristic of congenital esotropia - OKN asymmetry Temporal to nasal (T/N) Smooth, following and rapid refixation Nasal to temporal (N/T) Jerky inaccurate movements with halting refixation OKN asymmetry is present in all infants but becomes symmetrical by 6 months. Patients with congenital ET retain OKN asymmetry

27. Variants of essential infantile esotropia Ciancia syndrome Lang’s syndrome

28. Ciancia syndrome Early onset ET Bilateral abduction limitation Manifest-latent jerk nystagmus (fast phase in the direction of fixating eye) Increasing in abduction; decreasing in adduction Face turn towards fixating eye Fixating eye in adduction(null point in adduction)

29. Lang syndrome Early onset ET DVD Nystagmus Excyclodeviation of non fixating eye May be associated with torticollis

30. DIFFERENTIAL DIAGNOSIS Cranial nerve 6 th palsy Doll’s eye manouvere Duane’s retraction syndrome Changes in palpebral aperture, upshoot / downshoots on adduction CNS anomalies Down’s syndrome, Mobius , Cerebral Palsy, Albinism Accomodative ET/ Partially accomodative ET Cycloplegic refraction Nystagmus blockage syndrome Inverse relation between amplitude of nystagmus and degree of esotropia

31. Etiology Unknown Multifactorial Heritable factors- monozygotic twins showing esotropia Developmental anomaly in first 4 months

32. Phenomenon of saccadic underactions Abnormal pursuits in amblyopia and alternating esotropia Temporal nasal asymmetry of optokinetic nystagmus Alternating esotropes - underaction of saccades of the covered eye (non fixating eye) When fixation was shifted to the other eye, the saccades became normal and those of previously fixating eye became underacting . This is phenomenon of alternating saccadic underaction .

33. In unilateral esotropia , with one eye amblyopic eye have underaction of saccades of amblyopic eye when normal eye fixates, but no underaction when amblyopic eye fixates Underaction of non fixating eye is an abnormal reflex activated by dominant eye only.

34. Management Depends on treatment of amblyopia Full cycloplegic refraction under atropine 1 % eye ointment Full hyperopic correction Occlusion

35. Occlusion therapy Conventional full time, fully opaque occlusion of dominant eye. At no point during the treatment, is binocular viewing allowed. Thus, patching is done for 3:1, 4:1 or 5:1 days for a 3,4 or a 5 year old child respectively. Above 6 years, the regime remains 6:1 for all ages.

36. Vision assessment done monthly. (fortnightly in infants). End point: free alternation of the two eyes which is equally maintained.

37. Surgery Large angle ET- earliest/ 4 months of age Small angle ET- proper hyperopic correction till 6 months or till examination can be done satisfactorily.

38. Factors to be considered Associated inferior oblique ‘v’ phenomenon Amblyopia therapy DVD Nystagmus Eccentric fixation or uncorrected amblyopia have unpredictable results.

39. Surgical guidelines MR surgery is more effective LR surgery Mono-ocular recession-resection or bimedial recession MR 1mm surgery corrects 3-4.5 PD of deviation LR 1mm surgery corrects 2-3 PD of deviation

40. Post operative results According to Von Noorden , four possible outcomes are as follows: OPTIMAL GOAL DESIRABLE GOAL ACCEPTABLE GOAL UNACCEPTABLE GOAL

41. ROLE OF BOTULINUM INJECTIONS ALTERNATE TO SURGERY IN ADULTS EFFECTS LAST FOR SHORT DURATION , PROLONGED IN INFANTS

42. ACQUIRED OR LATE-ONSET NON-ACCOMODATIVE ESOTROPIA Onset after infancy No accomodative factors and no neurological cause (excluded by CT/MRI) ‘acquired essential (non- accomodative ) esotropia . Basic type or convergence excess type Rarely divergence insuffiency may be present. Management- Surgery with better binocular visual potential than infantile esotropia

43. MICROTROPIA Ultra small angle ET Missed by ordinary methods of examination Usually have amblyopia of one eye with variable levels of binocularity 1. Primary 2. Secondary(residual deviations after surgery)

44. PARK’S MONOFIXATION SYNDROME Macular scotoma Good peripheral fusion with fusional amplitudes and gross stereopsis

45. LANG’S MICROTROPIA Small angle (<5˚) heterotropia Harmonius ARC Mild amblyopia Partial stereopsis Based on fixation pattern Cover test Type 1 Central fixation Shows tropia Type 2 Eccentric fixation without identity Shows tropia Type 3 Eccentric fixation with identity Does not pick up a tropia

46. Type 3- eccentric fixation with identity implies that angle of anomaly is same as the eccentricity of fixation.

47. FINDINGS IN MICROTROPIA CONSISTENT Amblyopia ARC Relative scotoma on fixation spot Normal or near normal fusional amplitudes Defective stereoacuity VARIABLE Size of deviation (5˚-8˚) Foveal or non- foveal fixation Relationship between degree of eccentric fixation and angle of anomaly Presence or absence of anisometropia Positive or negative cover test

48. DIAGNOSIS Macular scotoma by Bagolini’s glasses or 4PD test. Presence of amblyopia and associated refractive error should be detected.

49. MANAGEMENT Treat amblyopia with occlusion therapy Good prognosis if treated in younger children.

50. ACUTE CONCOMITANT ESOTROPIA Sudden presentation c/o diplopia 2 types: Those which manifest after the fusion has been interrupted by a patch or occlusion for a short time. Those which have no such interruptions to fusion but have very poor fusional control, which may be further compromised by physical or emotional stress.

51. First type- spontaneously resolve within 6 months. Second type- Surgery/ prismatic neutralisation in case of small angle ET.

52. CYCLIC ESOTROPIA Regular cycles of presentation Usually 24-48 hours of squint alternating with same duration of no squint. Squint days: 1. large angle ET (40-50PD) 2. sensory anomalies 3. squint is consistent.

53. No squint days: 1. BSV with good fusional amplitudes 2. No latent squints Lasts for a few months to years before they become fully manifest squints Surgery as per deviation on squinting days gives satisfactory results.

54. NYSTAGMUS BLOCKAGE SYNDROME Infantile ET is associated with manifest-latent and latent nystagmus . However, there is a special form of nystagmus which has a dampening mechanism with eyes in adduction Inverse relationship between ET and nystagmus Nystagmus is present when eyes are straight and it disappears when eyes are locked in ET. Management: Faden with or without B/L MR recession.

55. SENSORY ESOTROPIA Lost vision in one eye usually develops squint over a period of time. XT or ET depending on convergence tonus XT- in first year and after 8-9 years of age ET- after first year upto 8-9 years of age Refractive error and accomodative status of the straight eye needs to be evaluated before planning any cosmetic surgery

56. MANAGEMENT OF ESOTROPIA

57. NON SURGICAL MANAGEMENT OPTICAL ORTHOPTIC MEDICAL TREATMENT

58. OPTICAL CORRECTION Refraction and proper prescription including use of bifocals Use of prisms Purpose: Fusion and binocular vision Maintains relationship between accomodation and convergence mechanisms

59. PROPER CYCLOPLEGIA PROPER PRESCRIPTION- full cycloplegic correction with no over or under correction. BIFOCALS- In case of high AC/A ratio

60. Executive Half Segment Bifocals

61. Use of prisms Glass prisms- upto 7-8 pd over each eye Fresnel prisms- upto 25-30 pd

62. Orthoptic treatment Orthoptics does not eliminate the deviations but alters the sensory status to make the subject more capable of overcoming existing deviation. Anti suppression exercises Managing ARC Pleoptics

63. Anti suppression exercises Red filter Chieroscope

64. Medical treatment Miotics Cyclopegics Chemodenervation by botox

65. Miotics in accomodative esotropia Site of action- ciliary muscles Facilitates accomodation Reduces accomodative effort Hence, reduces accomodative convergence

66. Miotic agents Di-isopropyl- flourophosphate (DFP) Phospholine iodide ( Echothiophate )- 0.03%, 0.06% and 0.125% Demecarium bromide ( Humorsol )

67. Desirable end results after use of miotics is proper binocular alignment at all times, especially near work with accomodative tasks.

68. Cycloplegics To make patients accept full hyperopic correction To suppress accomodative convergence mechanisms and stimulate divergence

69. Use of botox in infantile esotropes This is still under trial by Scott and McNeer Infantile esotropes if aligned before 6 months can have good functional binocularity . While the surgical effect of botox in adult eye muscles is transient, effect in early infancy is permanent because of the changes in the developmentally immature muscles.

70. Initial overcorrection may restructure the ocular motility balance to yield better result ultimately. However on the negative side, associated changes of oblique overactions / AVpatterns / DVD may still require surgical correction.

71. SURGICAL MANAGEMENT PRE OP EVALUATION Assessment of vision and amblyopia therapy Measurement of deviation

72. Forced duction test To reveal restrictive pathology

73. Spring back balance test Jampolsky Assesses whether surgical adjustment of the muscles has disturbed the balance of passive muscle forces.

74. Muscle stretch test After disinsertion and passing sutures, muscle pulled towards the centre of cornea To reveal contracture and fibrosis

75. Choice of surgery- general principles Weakening Strengthening Aim- symmetrizing and not symmetric surgery

76. Esotropia with convergence excess Bimedial recession

77. Divergence insuffiency Bilateral LR resection

78. Basic eso Unilateral recession and resection Bimedial recession

79. Principle To split amount of surgery across two recti rather than single large surgery in single muscle alone If AV, with obliques overaction - vertical shifting of horizontal recti or slanting recession and resection can be done

80. Weakening procedures Recession Conventional Hangback Adjustable Vertical transposition of horizontal recti Slanting recession Retroequatorial myopexy

81. Recession Muscle is disinserted and reinserted to a point closer to its origin. Induces a slack/laxity Muscle becomes less effective Reinsertion to be done within its arc of contact Max recession defined by functional equator- depends on arc of contact

82. Max recession MR- 6mm LR- 8mm in adults Children- MR 5.5mm LR 7mm Minimum MR 3mm LR 4mm

83. Hang back recession Recession is done with long ends of the suture between the site of insertion and the muscle. This is indicated if supramaximal recession is intended and its difficult to pass sutures that posteriorly Or, there’s a risk of scleral perforation in high myopes

84. Weakening effect is more than a conventional recession because of a central (mid width) sag. A pseudotendon may form in the intervening space around the sutures which may lead to a late under correction.

85. Adjustable recession Ability to modify the position of a newly operated muscle by use of adjustable sutures. Indications: Large angle deviations where results may be inconsistent Reoperations/ previously injured muscles Incomitant starbismus with diplopia when precise post operative results are desired. Mechanical limitaions as in dysthyroid orbitopathy or musculofacial anomalies. Aberrant innervation in III nerve palsy or DRS

86. Retroequatorial myopexy ( Faden ) Posterior fixation suture Musle is sutures posterior to insertion farther than its limit of arc of contact. This shortens the lever arm and reduces the action of muscle in its field of action. No change in primary position if no recession is done along with Faden .

87. MR- 12-14mm LR-16-20mm SR- 14-16mm IR- 14-16mm More effective on MR; least on LR

88. Indications Non accomodative convergence excess esotropia (MR) Nystagmus blockage syndrome (MR) DVD (SR) Paralytic strabismus ( contralateral synergist) DRS ( contralateral MR) Additional weakening effect over recessed muscle.