Basics of Strabismus testing

Laura May, CO Madison Kincade

http://www.allaboutvision.com/conditions/strabismus.htm

1 4/14/2017 Strabismus

• Strabismus is any misalignment of the eyes • Estimated that 4% of the U.S. population has strabismus • Commonly described by the direction of deviation • Can be described by cause of strabismus

2 2 4/14/2017 Types of Strabismus • Esotropia = ET – E(T), E • Exotropia = XT – X(T), X • Hypertropia = HT – H(T), H • Dissociated Vertical Deviation = DVD • Measurements at near use ‘ symbol

3 3 4/14/2017 Testing Techniques

http://www.guldenophthalmics.com/products/index.php/occluder-short-handle-black.html

4 4 4/14/2017 Cover tests

• Cover-uncover test • Alternate prism cover test • Simultaneous prism cover test • Patch test (Marlowe)

https://ohioamblyoperegistry.com/about/

5 5 4/14/2017 Cover Test

6 6 4/14/2017 Uncover Test

7 7 4/14/2017 Alternate Prism Cover Test

25 PD

8 8 4/14/2017 Alternate Prism Cover Test

30 PD

9 9 4/14/2017 Simultaneous Prism Cover Test

6 PD

10 10 4/14/2017 Simultaneous Prism Cover Test

10 PD

11 11 4/14/2017 Estimation Techniques

• Hirschberg • Krimsky

12 12 4/14/2017 Angle Kappa

• The angle between the visual axis and the pupillary axis

13 13 4/14/2017 Motor fusion

• Types and normal ranges – Convergence • Near: 35-40 pd • Distance: 20-25 pd – Divergence • Near: 15pd • Distance: 7pd – Vertical vergence • 2-3 pd (base up/down) – Cyclovergence • 1-2 degrees http://www.guldenophthalmics.com/products/index.php/prisms/bv-15-b-16-set.html

14 14 4/14/2017 Vergences

Simultaneous control of eyes in opposite direction Convergence 1. Tonic – constant innervation tone to the EOM while awake 2. Accommodative – near reflex, near triad 3. Fusional – stimulus to maintain clear, single image 4. Relative – amount of BO prism person can handle 5. Proximal – controlled by awareness of near 6. Voluntary – ability of eyes to converge without stimulus Divergence 1. Tonic 2. Fusional 3. Relative Vertical 1. Tonic 2. Fusional

15 15 4/14/2017 NPC/NPA

• Near point of convergence (NPC) – Accommodative target moved towards patient’s nose, break point recorded when patient becomes XT – 10cm or less = normal • Near point of Accommodation – Prince rule used to measure – Tested monocular and binocularly http://www.west-op.com/berensaccommod.html

16 16 4/14/2017 Binocular Vision

• Worth 4 dot – SBV – Suppression – Diplopia • Titmus Fly – Stereo – Monocular clues

17 17 4/14/2017 Bagolini Striated Lenses

• Bagolini lenses test for: – Diplopia (ET/XT) – Fusion or Harmonious ARC – Suppression Scotoma – Suppression

18 18 4/14/2017 Detection and measure cyclotropia

• Double maddox rods • Synoptophore • Bagolini lens • Fundus photography

http://www.ophthalworld.de/lshop,showdetail,2004g,en,,vorhalter_und_leisten.neue_vorhalter_und_leisten,01130,8,Tshowrub-- vorhalter_und_leisten.neue_vorhalter_und_leisten,.htm

19 19 4/14/2017 Diplopia

• Testing in clinic • Monocular vs. Binocular • Treatments – Fresnel prism/ground in prism – Fogging/occlusion

http://www.medicalnewstoday.com/articles/170634.php http://www.eyecareandcure.com/ECC-Products/Occluders-Maddox-Rods

20 20 4/14/2017 AC/A ratio

• Gradient • Heterophoria

21 21 4/14/2017 Prism adaptation test

• Uses – Determine position of motor stability with acquired ET – Determine fusion potential – Determine risk of surgical over-correction

http://www.eyecareandcure.com.sg/fresnel-presson-prism35d-pi-4243.html?image=0

22 22 4/14/2017 Extraocular Muscles

http://marineyes.com/anatomy/muscles.html

23 23 4/14/2017 Extraocular Muscles

• Agonist: primary muscle that is moving eye • Antagonist: opposite muscle that is relaxing in the same eye • Synergist: muscle helping the eye move along with the agonist – Ispilateral synergist: same eye – Contralateral synergist: opposite eye – Yoke pair • Contralateral Antagonist: opposite eye that antagonist of the yoke pair in that eye

24 24 4/14/2017 Extraocular Muscles

• Herring’s Law: innervation to the EOM generated by yoke pairs/contralateral synergist. • Sherrington’s Law: reciprocal innervation. • Listing’s Law: no torsion occurs • Donder’s law: torsion is produced

25 25 4/14/2017 Yoke Muscles

26 26 4/14/2017 Extraocular Muscles

Muscle Primary Action Secondary Cranial Nerve Action Innervation Lateral Rectus Abduction None 6th CN Medial Rectus Adduction None 3rd CN Superior Rectus Elevation Adduction, 3rd CN intorsion Inferior Rectus Depression Adduction, 3rd CN extorsion Superior Oblique Intorsion Depression, 4th CN abduction Inferior Oblique Extorsion Elevation, 3rd CN abduction

27 27 4/14/2017 Cranial Nerve Palsies

Common causes of CN palsies Nerve Childhood Adult life > 55yr 3rd Trauma Intracranial Hypertension aneurysm and diabetes

4th Trauma Trauma Trauma 6th Idiopathic, MS, Space Hypertension, isolated benign, occupying diabetes, space increased ICP, lesion, Trauma occupying Trauma lesion

28 28 4/14/2017 Ocular rotations

Ductions vs Versions

29 29 4/14/2017 Ductions Horizontal Ductions Vertical Ductions

Supraduction Primary

Infraduction Adduction Cyclo-Ductions

Excycloduction

Abduction

Incycloduction

30 30 4/14/2017 Versions

Dextrosupraversion Supraversion Levosupraversion

Dextroversion Levoversion

Levoinfraversion Dextroinfraversion Infraversion

31 31 4/14/2017 Objective measurements

• Distance and near fixation • Nine diagnostic positions of gaze • Head tilts • Three-step test

http://schorlab.berkeley.edu/passpro/oculomotor/assets/images/Fig5-8.gif

32 32 4/14/2017 Pattern Strabismus

• A-pattern – Increasing ET or decreasing XT in up gaze – Decreasing ET or increasing XT in down gaze – A pattern must have 10 pd of incomitance • V-pattern – Increasing XT or decreasing ET in up gaze – Decreasing XT or increasing ET in down gaze – V pattern must have 15 pd of incomitance

33 33 4/14/2017 “VAVA”

• V-ET – most common • A-ET – most common in patients with Down syndrome • V-XT • A-XT – least common

http://www.cyber-sight.org/bins/volume_page.asp?cid=735-2858-4397-4403-4604-4619

34 34 4/14/2017 Abnormal Head Postures Characteristics Ocular Non-ocular Cover test Abnormal EOM Normal motility Straighten head - Able to passively Unable to passively straighten head straighten head - Longstanding AHP more difficult Occlusion When one eye occluded, When one eye occluded no head will straighten change in AHP Facial Asymmetry No or slight facial Marked facial asymmetry asymmetry Head position Turn and tilt vary Tilt and turn to side of depending on muscle contracted affected sternocleidomastoid muscle

35 35 4/14/2017 Esotropia

http://www.pedseye.com/strabismus_esotropia.htm

36 36 4/14/2017 Esotropia Infantile Acquired Congenital Accommodative Esotropia Nystagmus blockage syndrome Non accommodative Esotropia Ciancia Syndrome Acute comitant Esotropia Duane’s Syndrome Cyclic Esotropia Abducens palsy Sensory Esotropia Moebius Syndrome Divergence Insufficiency Divergence Paresis Spasm of near reflex Medial rectus restriction Lateral rectus weakness Consecutive and secondary Esotropia Small angle Esotropia Monofixation Syndrome

37 37 4/14/2017 Esotropia

• Classification – Age of onset • Infantile • Acquired – Role of accommodation and refraction • Non-accommodative • Refractive • High accommodative convergence to accommodation ratio • Partially accommodative

38 38 4/14/2017 Psuedoesotropia

• Prominent epicanthal folds • Narrow interpupillary distance • Negative angle kappa • Enophthalmos • Craniofacial malformations

39 39 4/14/2017 Congenital Esotropia

• Onset near birth • Usually large angle > 30PD • Associated vertical deviations common • Latent nystagmus • Cross fixation

40 40 4/14/2017 Accommodative Esotropia

• Onset age 6mo – 7yrs, average 2.5yrs • Moderate to high hyperopia • May be only partially accommodative • May have a high AC/A • Can be intermittent or variable • May decompensate

http://webeye.ophth.uiowa.edu/eyeforum/cases/129-accommodative-esotropia.htm

41 41 4/14/2017 Duane’s Syndrome

• Congenital miswiring of LR muscle with the branches from the medial rectus subnucleus • 3 clinical types • PF changes • Globe retraction

By Jmarchn - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20423772

42 42 4/14/2017 6th CN Palsy

• Signs and Symptoms – Limitation in abduction – Ductions > versions – D ET > N ET’ – Face turn toward paretic eye – ET larger in affected gaze – Can be unilateral or bilateral

http://entokey.com/neuro-ophthalmology-6/

43 43 4/14/2017 Duane’s vs VI palsy

Clinical Characteristics Type 1 Duane's VI Nerve Palsy Complete absence of Typical Not Always abduction Large ET in primary No Yes Globe retraction in Yes No adduction Lid fissure widening on Yes Possible abduction Upshoot/downshoot Yes No Diplopia Rare Yes Greater ET at distance Rare Common

44 44 4/14/2017 Monofixation Syndrome

• Small manifest ET • Central scotoma – 4 BO test • 4 BO prism held in front of either eye, watch for a shift and convergence • Mild amblyopia common • Reduced stereoacuity

45 45 4/14/2017 Exotropia

http://optometrist.com.au/exotropia/

46 46 4/14/2017 Exotropia

Infantile Acquired Congenital exotropia Intermittent exotropia Sensory exotropia Secondary or consecutive exotropia Convergence insufficiency exotropia Third nerve palsy Duane syndrome type 2 Sensory exotropia

47 47 4/14/2017 Exotropia

• Classification – Age of onset • Infantile • Acquired – Distance-near relationship • Basic (D=N) • Divergence excess (D>N) • Pseudo-divergence excess • Convergence insufficiency (N>D)

48 48 4/14/2017 Pseduoexotropia

• Positive angle kappa • Wide interpupillary distance • Wide palpebral fissures • Exophalmos • Narrowing lateral canthi • Hypertelorism

49 49 4/14/2017 Congenital Exotropia

• Onset by age 6 months • Associated vertical deviations • Large angle > 30pd • Latent nystagmus • May have associated neurological abnormalities

https://www.aapos.org/terms/conditions/49

50 50 4/14/2017 X(T)

• Broken down X • Monocular lid closure • Wider VF • No diplopia • Control – Good, fair, poor

http://www.omicsgroup.org/journals/peripapillary-staphyloma-in-a-child-with-intermittent-exotropia-2165-7920.1000424.php?aid=33470

51 51 4/14/2017 Convergence insufficiency

• Characteristics – Reduced convergence amplitudes – May c/o headaches, asthenopia and eye strain – May have intermittent diplopia – May have reduced NPC

52 52 4/14/2017 Convergence insufficiency

• Treatments – Pencil pushups – Stereogram – Computer orthoptics – Prisms

http://computerorthoptics.com/

53 53 4/14/2017 3rd Cranial Nerve

• 3rd CN – Superior division innervates • Superior rectus • Levator – Inferior division innervates • Inferior recuts • Inferior oblique • Medial rectus • Intraocular muscles

54 54 4/14/2017 3rd CN Palsy

• Characteristics – Ptosis – Dilation of pupil – Limitation of adduction, elevation and depression – Exotropia and hypotropia in primary – Accommodative weakness – May present as isolated extraocular muscle palsy

55 55 4/14/2017 Vertical Strabismus

http://www.cehjournal.org/article/understanding-detecting-and-managing-strabismus/

56 56 4/14/2017 Vertical Strabismus

Paretic Muscle Restriction Other SO palsy Brown syndrome DVD IO palsy Monocular Elevation Myasthenia Gravis Deficiency SR palsy CPEO Skew Deviation IR palsy Congenital fibrosis PSP

57 57 4/14/2017 4th CN Palsy

• Superior Oblique Palsy – Hypertropia of affected eye – AHP is common – Excylotorison – Positive Bielschowsky head tilt test – Can be congenital or aquired – Unilateral or bilateral

58 58 4/14/2017 4th CN Palsy

Congenital/long standing Acquired Diplopia Rare Present, but can be limited to paretic field Image tilting Absent Common Comitance Spread may obscure Characteristically paresis incomitant Abnormal head posture May persist on covering Disappears on covering eye eye due to contracture Facial Asymmetry Common Absent Past pointing Absent Present Old photos May show AHP Negative Amblyopia May be present Absent

59 59 4/14/2017 Unilateral vs Bilateral 4th

• Bilateral SO palsy – V pattern present – 10 degrees of excyclotorsion, may increase in downgaze – Reversal of HT on side gazes, tilts or oblique fields – ET maybe associated

60 60 4/14/2017 Bilateral 4th CN Palsy

61 61 4/14/2017 Parks–Bielschowsky three-step test

62 62 4/14/2017 Brown Syndrome

http://www.webhealthwatch.com/eye-disorders/treatment-and-care-of-brown-syndrome.html

63 63 4/14/2017 Brown Syndrome

• Inability to elevate in adduction – Duction = version • Hypotropia in primary and/or upgaze • Divergence on upgaze, V pattern • Etiology – Congenital, traumatic, inflammatory, iatrogenic

64 64 4/14/2017 IO palsy

• Inferior division of 3rd CN , look for MR, IR and pupil involvement • Test with 3 step test • Overaction of ipsilateral SO • AHP – turn to opposite side, tilt to affected side • Differential dx = Brown’s syndrome

65 65 4/14/2017 Brown vs IO palsy

Clinical Characteristics Brown Syndrome IO Palsy Limitation of elevation in Yes Yes adduction Overaction of ipsilateral SO No Yes Versions = Ductions with Yes No elevation in adduction Positive forced ductions Yes No Positive forced generations No Yes Positive head tilt test No Yes Pattern V A Incyclotorsion No Yes

66 66 4/14/2017 DVD

• Up-drift of eye occurring under cover or spoontaneoulsy during visual inattentiveness • Associated with: – early disruption of binocular development – Latent nystagmus – Horizontal infantile strabismus – Poor binocular VA • No associated HypoT deviation http://www.mattweedmd.com/news/

67 67 4/14/2017 Conclusion

• Types of strabismus – Horizontal/vertical – Dissociated deviations • Testing techniques – Cover tests – Special testing • EOM

68 68 4/14/2017

Questions?

69 69 4/14/2017