Assessment and management of strabismus conquest 10 feb 2011

33
Assessment and Management of Strabismus Fiona Crotty Head Orthoptist East Sussex Hospitals

Transcript of Assessment and management of strabismus conquest 10 feb 2011

Page 1: Assessment and management of strabismus conquest 10 feb 2011

Assessment and Management of Strabismus

Fiona CrottyHead Orthoptist

East Sussex Hospitals

Page 2: Assessment and management of strabismus conquest 10 feb 2011

Overview

• Development of Visual Acuity• Assessment of Vision in Infants & children• What is BSV and how does it develop?• Classification of squint• Assessment of squint• Management of squint

Page 3: Assessment and management of strabismus conquest 10 feb 2011

Development of Visual Acuity

• Dependent upon normal anatomical and physiological development

• Eye relatively well developed in full-term infant– Shorter axial length (more hypermetropic)– Shallow anterior chamber– Poorly differentiated fovea (complete by 4

months age)– Accommodation 90% accurate by 2 – 3 months

Page 4: Assessment and management of strabismus conquest 10 feb 2011

Development of Visual acuity (VEP’s)

Age Visual Acuity

Newborn 6/240

1 month 6/180 – 6/90

4 -6 months 6/18 – 6/6

3 years 6/6*

* Tested with single optotypes

Page 5: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision Birth to 12 months – forced choice preferential

looking

Page 6: Assessment and management of strabismus conquest 10 feb 2011

Assessment of vision 12 months – 2 years Cardiff Cards

Page 7: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision - Cardiff Cards

Page 8: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision – occluding glasses

Page 9: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision2 – 4 years Kay Pictures

Page 10: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision4 – 6 years Crowded logMAR

Page 11: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision – LogMAR vs. Snellens Type

• Snellens:– Traditional method– 6 metre test distance– Recorded as fraction e.g.6/60, 6/9– Inconsistent numbers & spacing of letters per row

• logMAR:– Decimal value, 0.0 =6/6 equivalent, 0.2 = 6/9.5 etc– Equal number of letters per row, consistent spacing– Greater range of acuity values & can be used at 3m– Preferred method for research and amblyopia testing

Page 12: Assessment and management of strabismus conquest 10 feb 2011

Assessment of Vision

Snellens Chart logMAR Chart

Page 13: Assessment and management of strabismus conquest 10 feb 2011

What is BSV?

• Definition of Binocular Single Vision (BSV)– The ability to use both eyes simultaneously so that

each eye contributes to a common single perception

• 3 levels– Simultaneous perception ( 2 images seen)– Fusion (Interpreting 2 images as one)– Stereopsis (3-D appreciation)

Page 14: Assessment and management of strabismus conquest 10 feb 2011

Development of BSV

• Newborn reflexes present – essential for BSV development

• Require continued use and normal visual experience– Postural reflexes: static (head position to body)

and stato-kinetic (head relative to space)– Fixation reflexes: fixation (foveal) and re-fixation

(target to target and maintained to moving object)

Page 15: Assessment and management of strabismus conquest 10 feb 2011

Development of BSV

Most neonates show coarse re-fixation1.Conjugate fixation 1st to develop (eyes follow

object together)2.Disjugate fixation (follow approaching object –

convergence)3.Fusional reflex (correct for change in image

position)4.Kinetic reflex (controlled accommodation &

convergence)

Page 16: Assessment and management of strabismus conquest 10 feb 2011

Development of BSV

• From aet 4/52 Attempts at convergence seen • 5-6/52 conjugate fixing and brief following –

neonatal misalignment common• 4/12 saccadic eye movements develop,

neonatal misalignments reduce• 6/12 – 8/12 normal BSV established

Page 17: Assessment and management of strabismus conquest 10 feb 2011

Risk Factors for Development of Squint

• Prematurity• Neuro-developmental delay• Motor control disorders eg cerebral palsy• Refractive error, failure to emmetropise• Family history

Page 18: Assessment and management of strabismus conquest 10 feb 2011

(Brief) Classification of Squint

• Manifest (Heterotropia)– Esotropia (convergent)– Exotropia (divergent)– Vertical– Unilateral or alternating– Constant or intermittent (in Primary position, or in

certain positions of gaze)– Accommodative

Page 19: Assessment and management of strabismus conquest 10 feb 2011

(Brief) Classification of Squint

• Latent (Heterophoria)– Esophoria– Exophoria– Vertical ‘phoria– Fully compensated– Poorly compensated

Page 20: Assessment and management of strabismus conquest 10 feb 2011

Left Esotropia

Page 21: Assessment and management of strabismus conquest 10 feb 2011

Cover Test, Esotropia (1 & 2)

Page 22: Assessment and management of strabismus conquest 10 feb 2011

Pseudo Esotropia

Page 23: Assessment and management of strabismus conquest 10 feb 2011

Right Exotropia

Page 24: Assessment and management of strabismus conquest 10 feb 2011

Cover Test, Alternating exotropia (3)

Page 25: Assessment and management of strabismus conquest 10 feb 2011

Intermittent Squint Brown’s Syndrome

Page 26: Assessment and management of strabismus conquest 10 feb 2011

Intermittent SquintDuane’s Syndrome

Page 27: Assessment and management of strabismus conquest 10 feb 2011

Cover Test, Esophoria (4)

Page 28: Assessment and management of strabismus conquest 10 feb 2011

Cover Test, Exophoria (5)

Page 29: Assessment and management of strabismus conquest 10 feb 2011

Assessment of squint

• Visual Acuity• Cover Test• Ocular Movements• Convergence• Fusion/Stereopsis?• Measurement of angle (prisms)

Page 30: Assessment and management of strabismus conquest 10 feb 2011

Management of Squint

• Orthoptic assessment• Cycloplegic refraction & fundoscopy– Correct significant refractive error– Allow for refractive adaptation (up to 18/52)– Occlusion treatment for amblyopia (patches,

atropine)– Orthoptic exercises (intermittent deviations)– Surgery

Page 31: Assessment and management of strabismus conquest 10 feb 2011

Summary

• Early intermittent neonatal misalignment common between birth and 2-4 months

• BSV well established from 6 months• Sensitive period for development of vision and

binocular reflexes• Suspected squint after 4 months (corrected)

age should be referred for Orthoptic assessment

Page 32: Assessment and management of strabismus conquest 10 feb 2011

Acknowledgements

• Thank you to Manuel Saldana for his kind permission to use the video clips

Page 33: Assessment and management of strabismus conquest 10 feb 2011

Thank you