Esotropia

• Primary SOT


  1. Original problem was SOT

  2. Broken down into constant and intermittent

  3. Constant=always SOT

  4. Intermittent=SOT/SOP
• Secondary SOT


  1. Secondary to pathology which affects foveal function

  2. Accom active

  3. Vision loss during childhood
• Consecutive SOT


  1. Prev XOT

  2. Probs after surgery

  3. Overliberal to prevent redivergence
• Constant Partially Accommodative SOT

  • Hyperopia/associated with unilateral amblyopia
  • Size inc without Hyperopic rx/at near if greater than 10 diopters/when they accom
• Infantile Esotropia


  • Congenital/onset before 6 months
  • Cross fixation/~30% neurological and developmental problems
• Cover Test


  • Large angle, >40 diopters/ alt SOT=no amblyopia but if they had surgery then may have constant unilateral with amblyopia. Should look for DVD=dissociated vertical divergence and manifest latent nystagmus
  • May have a vertical deviation
• Dissociated vertical divergence


  • Before 2 years old
  • Eye spontaneously drifts upwards when covered/daydreaming
  • Extort as elevates, intorts as depresses
  • Spielmann occluder
  • Bilateral and asymmetric
  • Hard to measure
• Ocular Movements Associated with Infantile SOT


  • IO overacts/abduction often
• Nystagmus


  • Manifest latent=present when both eyes are open but inc when one eye is covered
  • Vision better on adduction and no nystagmus/reduced
  • Nystagmus amp inc on abduction
  • Clinically may not be able to see manifest component
  • Infantile=manifest latent nystagmus
• Nystagmus blockage syndrome


  Manifest only, infantile horizontal nystagmus, SOT inc, nystagmus red in amp so px can see more
• Compensatory head posture


  • Face turn to fixing eye to reduce nystagmus
  • So if fixing is LE turn head to left hand side so it adducts
  • Works because of cross fixation
• Asymmetry OKN


  • Temp to nasal is normal but nasal to temporal=weak
• Assessment of binocular function

  • Unlikely to have any binocular function and because onset is early, might find suppression responses
  • Maldevelopment of cerebral visual motor pathways
• Early Onset Non-Accommodative esotropia


  • 6 months to 2 years
  • Refractive error insignificant to angle
  • Amblyopia is common as don't alternate
  • BSV=poor
  • Near deviation ~= to distance as don't accommodate
• Late onset non-accommodative esotropia

  • Intermittent originally
  • Dip during early rapidly moves to suppression
  • Correcting refractive error wont make a difference bc accom unaffected
  • Neurological problems=refer!
• Myopia associated with esotropia


  • Associated with high levels of myopia
  • Prevalence of SOT/vertical tropia inc
  • Might affect pulley systems
• Fully accommodative esotropia


  • Intermittent/always hyperopic rx/+2-+7
  • To see clearly: accommodate and converge- Need specs
  • Cover test: Full rx: well controlled SOP at all distances
  • Without: SOT/SOP alt/unilateral
  • Binocular functions are good with rx
• Convergence Excess esotropia


  • Usually hyperopia, sometimes=emme, rare=myopia
  • Due to high AC/A
  • Cover test with specs: SOT at near with specs with accom target, SOP + BSV at near with light, SOP + BSV at distance
  • Cover test w/o specs: SOT at all distances
• Near Esotropia


  Cover test: SOT at near, SOP + BSV at distance but equal vision
• Distance Esotropia


  • Cover test: SOP + BSV at near, SOT at distance initially but can become more constant
  • Condition=rare. Exclude 6th nerve palsy
• Cyclic esotropia


  • Rare
  • SOT on squinting day
  • SOP + BSV on non squinting day
• Strabismus and birth history

  • Strab More common in premature/low weight
  • Forceps/birth trauma?
• Amblyopia and esotropia


  • Constant: common
  • Alt constant: uncommon
  • Intermittent: uncommon unless decompensating and untreated in childhood/anisometropia
  • Consecutive SOT: common
• Expected finding for ocular motility
• Controlled binocular acuity


  1. All px with intermittent if co-op allows

  2. Near: snellen/budgie

  3. Distance: logmAR

  4. Get them to read down the chart and every couple of lines, cover an eye and see if they straighten

  5. Can be done subjectively too and ask if they get diplopia
• Results for controlled binocular acuity

  • Convergence excess SOT: near SOT as they accom as they read further down the chart
  • Near SOT: SOT present all the time
  • Fully accom SOT: With Rx, SOP all the way down
  • Record line before as still binocular
• Post-operative diplopia test


  1. Px who are constant but no binocular function. May have suppression.

  2. If they are considering surgery to look functionally normal

  3. May get dip after surgery

  4. Measure angle of deviation with prisms. First, base opposite deviation and then same side. Prism inc until notes dip. Px fixates light. Can combine with red-green goggles

  5. If even after small correction, gets dip=bad candidate
• Aims of investigation


  • Diagnose type of strab
  • Suppression- cosmesis purposes
  • Measure angle/density
  • Post-op dip test
  • Can you restore BSV in all positions of gaze?
• First stage of management of esotropia


  1. Refraction: cyclopentolate/atropine

  2. Fundus and media exam

  3. Correction of ametropia

  4. Amblyopia therapy esp if under 7 years

  5. Ensures you don't make them decompensate

  6. SOT + Supression + less than 5 check density with sbisa bar
• Purpose of first stage management


  • Improve alignment of visual axes
  • Enhance ARC
  • Restore BSV= if can't, cosmesis
• Conservative management options


  • Optical: prisms/manipulate rx
  • Orthotic exercise
  • Observe/monitor
• Non-conservative management options


  • Surgery/botox
• Hyperopic glasses


  • Relax accommodation so in turn convergence
  • Full plus rx
• Prisms


  • Base out resolves dip
  • Do post-op dip test
  • Assess binocular function before surgery
• Orthoptic exercises


  1. Want to give less convergence

  2. Want to improve negative relative convergence- give cats and cut hoes in tummies

  3. To EXERCISE: give base IN prism
• Surgery


  1. Angle is greater at near=both MR recessions

  2. Angle is greater at distance= both LR recessions

  3. Near=distance= 1 x MR 1 x LR

  4. Px sleeps, do half the surgery, tie off muscles on adjustable sutures

  5. Wake up px, fine tune by pulling on sutures to get eye as straight as possible

  6. Good for pxs with poor VA before surgery
• Botulinum toxin type a injection


  • Injection
  • Neurotoxin which paralyses muscle it is injected into so MR for SOT
  • LR has advantage therefore eye moves out
• Advantages of Botox


  • Results=temp
  • Consecutive=already had surgery
  • Residual=reduces deviation so px may be able to regain control
  • Secondary=poor vision in one eye
  • Good for px who are unfit for anaesthesia
  • Good for confirming if px at risk of intractable dip using post-op test
• When to refer to HES


  • All chn under 5 years old
  • Recent onset - immediately if incomitant/neurological worries
  • Associated with pathology
  • Px becoming worse
  • Reconstructive surgery
  • Px you cant treat/manage
  • Unsure diagnosis
  • Amblyopia therapy - referral?
  • Symptomatic px that you cant treat
• Before referring to HES


  If not urgent:

  Refract and prescribe

  Full rx if hyperopia

  Cycloplegia if under 12

  Give full cyclplegic rx