Week 9 - Management of concomitant strabismus Flashcards

1
Q

What factors need to be considered when assessing suitability for treatment?

A

• Age
• Age at onset
• Type of strabismus
• Angle of strabismus
• Depth of sensory adaptations
• Cooperation of patient and parent

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2
Q

Age:

A

• under 4 years - no co-operation for exercises
Rx and occlusion possible only
• Over 8-9 years - not possible to restore BSV:
cosmetic treatment only
• Most adults have come to terms with the strabismus and require refraction only. Some may want cosmetic surgery

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3
Q

Age at Onset

A

• Very important
• To establish if the onset was within the first year (Px is more likely to have eccentric fixation, DVD, latent nystagmus)
• Next establish if onset is within the first 3 years
- Younger the Px is at onset and the longer time to presentation, the worse the prognosis.
- May never have developed binocularly driven cells and therefore cannot expect to obtain BV
• If very recent onset the Px is more likely to have distressing symptoms and may require immediate referral (esp. if incomitant)

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4
Q

Type of strabismus:

A

• some Pxs respond better to refractive/orthoptic treatment than others

• different methods of treatment are more appropriate for different types

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5
Q

Angle of Strabismus

A

• the greater the angle the worse the prognosis
• Intermittent squints better prognosis
• >20^- surgery indicated
• 15-20^ - other factors must be favourable for orthoptics
• <15^ - good for orthopties
• <6^ - microtropia, no orthopties necessary

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6
Q

Depth of Sensory Adaptations

A

• the deeper, the worse the prognosis

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7
Q

Cooperation of Patient and Parent

A

• must have high levels of interest and perseverance and reasonable intelligence
• parents must give time for supervision of exercises

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8
Q

Accommodative Esotropia types:

A

• Fully accommodative esotropia
• Esotropia with Accomodative Element
• Convergence excess - High AC/A ratio

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9
Q

Fully Accommodative Esotropia presentation

A

• Deviation is secondary to the presence of hyperopia
• Excessive accommodation for distance and near stimulates excessive convergence sufficient to cause a strabismus
• Onset usually 2-5 years; coincident with the increased use of accommodative effort
• AC/A ratio is usually normal
•BSV present in nearly all cases; may have microtropia if anisohyperopic
• Usually no or only slight amblyopia, unless strabismus is present for a long time

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10
Q

Fully accommodative esotropia: Management

A

• Correction of refractive error
• full cycloplegic Rx for constant wear
• Review 6-8 weeks later
• Check that no more latent hyperopia has become manifest and alter Rx if big difference
• Check state of BV and microtropia if anisometropia present

• If amblyopia worse than 0.3, may require period of direct part-time occlusion if under 7 years.
NB if microtropia present, VA will never be equal
NB Often a refractive error is all that is necessary

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11
Q

Esotropia with Accommodative Element presentation

A

• Constant Esotropia but increases with accommodative effort i.e without glasses
•Associated with hyperopia but residual angle still present with when corrected
• Usually amblyopia
•Onset 1-3 years; insidious
• BS depends on the age of onset; usually not present, but may have ABSV if small angle
• Associated vertical deviation common (I0 overaction of one or both eyes)

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12
Q

Esotropia with Accommodative Element: Management

A

• depends on the size of the residual angle.
• Referral is required in all cases
• full cycloplegic result given
• treat any amblyopia by occlusion
•May require surgery for residual angle with glasses if >25^

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13
Q

Convergence excess presentation:

A

• High AC/A ratio (>6:1)
• Strabismus at near only OR angle much greater at near
•Strabismus may only be present when looking at fine detail
• Onset 2-5 years, occasionally earlier
• Most have NBSV, rarely a microtropia
• Amblyopia rare (except in anisometropia)
• Most hyperopic but some are emmetropic or even myopic.
• It is important to differentiate convergence excess from non-accommodative NEAR SOT (has normal AC/A ratio) and undercorrected hyperopia ( e.g. do cycloplegic).

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14
Q

Convergence excess: Management Depends on…

A

•Depends on the AC/A ratio
• Also if near deviation is >25 - 30^ refer for surgery

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15
Q

Convergence excess: Management

A
  • correction of refractive error - full cycloplegic Rx, unless Px is myopic then give a slight undercorrection
  • amblyopia treatment (if necessary) by PT occlusion
  • Bifocal spectacles - find an add that eliminates near deviation (by CT)
    enabling PX to maintain comfortable BS with adequate binocular VA for all near activities
  • Start with +1.00 Add and increase in 0.50 steps
  • Try Fresnels on one month trial
  • Give large flat top seg set high bisecting pupil
  • Carefully fit and give full instructions
  • Gradually reduce add in time and discard if possible
  • Use a bar reader to establish BSV
  • Problem: dependency on add by young adults, poor fitting and compliance by children and wear and tear
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16
Q

Convergence excess: CL Mangement?

A

• Contact Lenses - Calcutt (1984) reported that CLs (sometimes with extra +1.00D) reduced the angle by up to 15^, often producing a latent deviation and useful BSV. Needs further trials

• Orthoptics for use without the Rx - minority of Pxs > 6 years; good cooperation and small deviations

17
Q

Convergence excess: Management: Increase VA? Surgery?

A

• Increase binocular VA - increase-ve fusional reserves (usually needs some optical correction to achieve)

• Of minimal value on its own but can be useful in conjunction with other treatment or surgery

• Surgery - Bimedial Recessions

18
Q

Non-Accommodative Esotropia’s:

A

• Constant
• Intermittent

19
Q

Non-Accommodative Esotropia’s: Constant

A

• Onset 1-2 years
• Strabismic amblyopia common
• Often have an associated vertical deviation

20
Q

Non-Accommodative Esotropia’s: Intermittent (Near)

A

• Thought to be due to high proximal convergence or high tonic convergence
• Ortho or small SOP on distance fixation, Moderate/large SOT for near

• No amblyopia
• Often no significant refractive error
• Normal or low AC/A ratio
• Normal near point of accommodation
• No reduction in angle with plus lenses
• Normal sensory and motor fusion

• SURGERY

21
Q

Non-Accommodative Esotropia’s: Intermittent (Distance)

A

• Rare
• SOT for distance, SOP for near
• No significant refractive error
• VA normal and equal
• Full ocular movements (differentiates 6th nerve palsy or dysthyroid eye disease)
• SURGERY /BOTOX

22
Q

Non-Accommodative Esotropia’s: Intermittent (Cyclic)

A

• Esotropia occurring at regular intervals of time, BSV at others
• Usual pattern = 24 hrs SOT/ 24 hrs BSV = “alternate day strabismus”
• Onset 4-5 years or older
• Most emmetropic with equal VAs
• Diplopia rare
• Gradually becomes constant - then surgery can be considered
• Often associated with a psychogenic disturbance

23
Q

Consecutive Esotropia

A

• Spontaneous - following XOT (rare - occurs with DVD)
• Post-operative - following overcorrection of an XOT

24
Q

Symptomatic (secondary) esotropia

A

• Following severe visual loss in childhood, due to muscle tonus

25
The management of non-accommodative SOT is almost always…
• Almost always surgical/BOTOX but **can try** • Can try prism for distance SOT where angle <10 A (Use Fresnel lens initially - adaptation) • Correct the refractive error to remove any asthenopia (independent of the deviation) • Any amblyopia must be treated
26
Infantile Esotropia:
. Occurs before 6 months (usually 3-6 months) • Usually large angle (>40 A) • Same angle distance and near • Crossed alternating fixation • Less than half have ambyopia with eccentric fixation • Latent nystagmus develops later • DVD - develops later around 18 months Looks like a bilateral L palsy (distinguish by "dolls head" movement) Cross Fixation • **ALWAYS REQUIRE SURGERY!!!**
27
Nystagmus Blocking (or compensation) Syndrome
• Convergent strabismus is adopted to lessen the nystagmoid movements which are reduced on convergence of the eyes • Pxs head usually turned away from side of fixing eye - produces greater convergence of this eye.
28
Distance exotropia: description
• Manifest for distance fixation only, usually intermittently but may be constant • Most apparent during inattention, ill health and fatigue, and in bright light • Mostly females • Little refractive error • VA usually good and equal • Usually no symptoms as the sensory adaptations are good • Px may not have known about strabismus until told by others • **AC/A may be high in simulated** type or they have increased fusional control • **True type is unaffected by AC/A or fusion**
29
Distance exotropia: Management
• Diagnosis of **True or Simulated 1st** • Correction of myopia or anisometropia • Low degrees of hyperopia best left uncorrected- unless surgery is going to be planned or amblyopia potential • Where angle is <15^ and BSV maintained most of the time, optical &/or orthoptic treatment may be of benefit - but usually only in the short term to delay surgery • Optical:negative lenses can be successful in the short term, where accommodation is good • Prisms (full base in - then gradually reduce) - short term • Tinted spectacles - useful in countries with high light intensity - again only short-term- high illumination has a dissociation effect • Most require referral for surgery • Orthoptist will use Newcastle Control Score to decide when Sx is required • **True - Bilat Lateral Rectus Recession** • **Simulated MR Resection with LR Recession in one eye**
30
Near Exotropia (Convergence Insufficiency) presentation
• Most commonly occurs in the mid-teens when reduced convergence &/or increased myopia break down the BV, can be in adults - Presbyopia with > near add • Typically XOP at distance XOT at near • Pxs present with symptoms (diplopia, asthenopia) • Usually equal VAs, poor or no convergence, NRC and normal sensory fusion with poor positive fusional amplitude • Often myopic
31
Near Exotropia (Convergence Insufficiency): Management
• If strabismus is constantly manifest for near and angle >25^ - refer • For smaller angles and only occasionally manifest: - Correct any myopia (this may be enough to make deviation latent) - Orthoptics - exercise base out prism vergences and Improve Conv Near Point if reduced - Prisms - base In just sufficient to enable BSV for near (Usually tolerated for distance) - gradually reduce the strength of the prism and combine with orthoptics - Most importantly improve convergence near point - If no improvement - refer for surgery.
32
Constant Exotropia:
• Constant divergent strabismus, equal angles distance and near • Onset in early childhood: no symptoms, no sensory fusion • Closure of one eye in bright light • Often alternating, with equal VAs; homonymous fixation
33
Constant Exotropia: Management
• Surgical correction for cosmetic (or occasionally functional) • Occasionally in children <7 years old - try-ve additions to eliminate strabismus on the CT in conjunction with exercises to establish BSV • Gradually try to phase out the -ve add over several years • If a divergent strabismus has a vertical component - orthoptics not successful
34
Consecutive Exotropia:
• Spontaneous - usually occurs following early onset partially accommodative esotropia with a high degree of hyperopia. • Develops as the amplitude of accommodation decreases, or precipitated by the late correction of hyperopia •Post-operatively - usually several years after surgical correction of accommodative SOT - especially if hyperopic correction is now prescribed
35
Consecutive Exotropia: Management
• partial correction of hyperopia + Base out prism • vergence exercises sometimes helps • remedial surgery
36
Symptomatic (Secondary) Exotropia
• Due to severe loss of vision in one eye in adult life • Management = Cosmetic surgery
37
Onset of Exotropia before 1 year old
• usually symptomatic (or secondary) due to visual loss from birth • rarely congenital exotropia, often with nystagmus and DVD Management • No optometric treatment - refer