Diagnosis of Strabismus and Amblyopia in a Primary Care Setting

1. Diagnosis of Strabismus and Amblyopia in a Primary Care Setting Valerie M. Kattouf O.D. F.A.A.O., F.C.O.V.D Associate Professor Illinois College of Optometry

2. EPIDEMIOLOGY Strabismus / amblyopia during 1st 6 years of life 5 % of the population

3. HEREDITY STATISTICS • 2 or more family members with strabismus • 49% Esotropia • 37% Exotropia • Frith & Brewer : 150 strab subjects • 70% = (+) Family History of Strabismus • Richter • 30-50%siblings of strabismic patients exhibit strabismus IF one or both parents are affected • Chimonidou • 96.5% of siblingsdeveloped strabismus of SAME TYPE as sibling,51%at SAME AGE

4. Examination of a Strabismic /Amblyopic patient • Case History • Visual Acuity / Refraction • Eccentric Fixation • Measuring the Deviation • Comitancy • Fusion • Anomalous Correspondence

5. OVERVIEW • What direction do the eyes deviate? • Horizontal (x axis) • Esotropia (inward) • Exotropia (outward) • Vertical (y axis) • Hypertropia (upward) • Hypotropia (downward) • Rotational (z axis) • Cyclotropia

6. OVERVIEW • How much of the time do the eyes turn? • Constant • All of the time • Intermittent • From 1-99% of the time • Never • Not a strabismus • phoria

7. OVERVIEW • At what distance does the turn occur? • Distance only • Near only • Distance and near

8. OVERVIEW • Does the deviation change with a change in direction of fixation? • Comitant • Deviation remains the same in all 9 cardinal positions of gaze • Deviation remains the same with either eye fixating • Non-comitant • Magnitude of the deviation changes while doing versions • Magnitude of the deviation changes with either eye fixating

9. Strabismus / Amblyopia :Associated Conditions with Increased Duration • Suppression • Amblyopia • Eccentric Fixation – concern with amblyopia ONLY! • Anomalous Correspondence

10. Diagnosis of Amblyopia

11. AMBLYOPIA • Definition • A unilateral or infrequently bilateral condition in which the BVA is less than 20/20 in the absence of any pathologic anomalies BUT with at least one or more of the following conditions • Amblyogenic Anisometropia • Constant Unilateral Strabismus • Amblyogenic Bilateral Isometropia • Amblyogenic Uni/Bi Astigmatism • Image Degradation Ciuffreda

12. Detecting Amblyogenic Risk Factors

13. Potentially Amblyogenic Refractive Errors • ISOMETROPIADIOPTERS • Astigmatism > 2.50 • Hyperopia > +5.00 • Myopia > -8.00 • ANISOMETROPIA • Astigmatism > 1.50 • Hyperopia > +1.50 • Myopia > -3.00

14. Case Example

15. 8 year old male • Refraction • -0.25 –4.00 x180 20/50 PHNI • Pl –3.50 x 180 20/30 • Cover Test : ortho • Stereopsis : (+) RDS • Dilated Examination 

16. Case Example: 8 year old male

17. Eccentric Fixation

18. ECCENTRIC FIXATION (EF) • What is it? • condition in which the amblyopic patient does not use the central foveal area under MONOCULAR conditions • Seen in STRABISMIC AMBLYOPES • Esotropia*** – nasal EF • Exotropia – temporal EF

19. ECCENTRIC FIXATION

20. ECCENTRIC FIXATION (EF) • Classification(4  nasal EF OD) • Location / Direction • Magnitude • Stability • Laterality

21. ECCENTRIC FIXATION • Assessment : VISUOSCOPY • Relationship between VA & EF : Linear • Effects on Prognosis and Treatment of Amblyopia

22. VISUOSCOPY • Set the target on ophthalmoscope • Occlude the amblyopic eye • Focus on the retina as if doing direct • Dim the light source • Ask the pt to look at the target center • Determine if the target is centered over the foveal reflex • Occlude the good eye and repeat • Identify the retinal location used to fixate • Record direction, magnitude, stability & eye

23. ECCENTRIC FIXATION (EF) Why does it matter???

24. Clinical Significance of Eccentric Fixation • Relationship between VA and EF • Prognostic factor for Amblyopia Tx. • EF may affect other diagnostic findings

25. Clinical Significance of Eccentric FixationHow is EF related to VA? • Best Visual Acuity ALWAYS at fovea • 20/20 = Fovea • high cone density • small receptive field • large cortical representation • Weymouth (1958) • investigated change in VA w/ change in eccentricity

26. How is EF related to VA? Visual Acuity Findings of Schapero

27. Case Example

28. 5 y.o. Male • Cc: Failed school screening • VA DVA NVA 20/25 20/32 20/400 (PH = 20/300) 20/200 • Cover Test (very poor fixation OS) • 0rtho • Stereo • (-) Fly, (-) forms

29. 5 y.o. Male • Retinoscopy • +8.00 -2.50 x 135 20/60 (20/30 w/ -1.00) • +10.00 – 2.50 x 045 20/300 • Cycloplegic ret • +8.50 -2.00 x 135 • +10.00 -2.50 x 045 • DFE • C/D 0.2 rd, wnl • wnl

30. 5 y.o. Male • Assessment / Plan • Likely strabismic amblyopia (vs. anisometropic) • Rx given • OD +7.00 -2.00 x 135 • OS +9.00 -2.50 x 045 • Occlusion therapy OD x 4-6 hours daily begin once Rx is received • RTC 6 weeks

31. Assessing the Strabismic Deviation (without a formal cover test!)

32. Hirschberg / Kappa Evaluation of light reflexes

33. With which patients is the Kappa / Hirshberg Evaluation most useful?

34. HIRSHBERG / KAPPA TESTS • Information gathered : • direction of strab • laterality • estimation of magnitude • estimation of frequency • Mechanism of test : • Compare <K of strab eye from : • when eye fixates monocularly • to when it deviates under binocular conditions

35. Krimsky Determining magnitude of the strabismic angle from a Hirshberg/Kappa evaluation

36. Krimsky Test(quantifies Hirschberg) Procedure • Perform Hirshberg • Examiner places himself on the side of the deviated eye • Place prism in front of fixating eye • Add prism until the corneal reflex in the deviating eye looks symmetrical with that of the fixating eye • The amount of prism necessary to achieve this = the Magnitude of the Deviation

37. Bruckner Test Evaluation of pupil reflex

38. Bruckner Test Procedure • use direct ophthalmoscope @ 1M from pt (scope set @ plano) • Room is dark / Pt looks at light • Look through the scope as you shine the light at the bridge of the pts nose • With the pt optically corrected look at the orange - red retinal reflexes • Compare the color and brightness btw the 2 eyes WHITER & BRIGHTER REFLEX : STRABISMIC EYE

39. Cover Test

40. Commonly Seen Strabismic Presentations

41. Vertical Deviations

42. Abnormal Head Position • Head Tilt • SO - tilt toward OPPOSITE shoulder • IO - tilt toward SAME shoulder

43. Brown’s Syndrome

44. BROWN’S SYNDROME : Clinical Characteristics • Deficiency of elevation in ADD • Less elevation deficiency in midline • Minimal or no deficiency in ABD • Minimal to no SOOA • Divergence in up gaze (V pattern) • Positive Forced Duction • Widening palpebral fissure in ADD • Downshoot in Adduction • Anomalous Head Posture • Primary position Hypotropia

45. Innervational Etiology

46. Duane’s Retraction Syndrome

47. Duane’s Retraction Syndrome • Marked limitation / absence of ABDuction • Normal or restricted ADDuction • Globe retraction and narrowing of palpebral fissure upon ADDuction

48. Variations of Duane’s • Type I - dec ABD, normal/slight dec ADD • Type II - dec ADD, normal/slight dec ABD • Type III • dec ABD and ADD, XT • ALL TYPES • narrowing of palpebral fissure • globe retraction on ADD

49. Non-comitant deviations Can be measured with ACT in various Diagnostic Action Fields

50. AV SYNDROMES • V Pattern ET - inc. down gaze, decrease up gaze 15 ET 20  ET 30  ET XT - inc up gaze, decrease down gaze 30  XT 20  XT 10  XT