Ophthalmology Book

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Strabismus

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  1. Epidemiology
    1. Accounts for 50% of Amblyopia (most common cause)
  2. Types
    1. Esodeviation (Cross-Eyed)
      1. Both eyes turn inward
      2. Accounts for >50% of ocular deviations in children
    2. Exodeviation (walleye)
      1. One eye turns outward while other eye faces forward
      2. Deviation most evident with distant vision
      3. Parents often note changes on a bright day
        1. Eye deviates outward
        2. Child closes one eye
    3. Fourth Cranial Nerve palsy (superior oblique palsy)
      1. Eye rises when Head Tilted to side of palsy
      2. Findings
        1. Hypertropia (deviating eye turns up)
        2. Hypotropia (deviating eye turns down)
  3. Signs: Screen at every well child check
    1. Test Specifically for strabismus
      1. Only 50% children with strabismus have obvious defect
  4. Signs: Organized by strabismus type
    1. Manifest (Tropia): Strabismus that is always present
      1. Corneal Light Reflex
      2. Cover-Uncover Exam
      3. Bruckner Test (Red Reflex)
      4. Fixation and following
    2. Intermittent Strabismus
      1. Healthy newborns develop alignment after age 4 weeks
      2. Intermittent exodeviation under 6 months
      3. Esodeviation much more likely to be pathologic
    3. Latent (Phoria): Present if binocular vision blocked
      1. Only found when specifically tested
      2. Cover-Uncover Exam
  5. Signs: Small-Angle Strabismus (Accommodative esotropia)
    1. Identified with Cover Testing
    2. Seen in Farsighted toddlers
    3. Corrected with glasses or bifocals
    4. Abnormal use of accommodative convergence
      1. Normal reflex for near vision
      2. Farsighted children use convergence all the time
  6. Screening
    1. General
      1. See testing above
      2. Photoscreening (picture of eyes and Red Reflex)
        1. May be used in future for mass screening
    2. Timing
      1. Screen frequently in first 3 years of life
      2. Example protocol: 8, 12, 18, 25, 31, 37 months of age
      3. Early diagnosis results in best outcome
    3. References
      1. Williams (2002) BMJ 324:1549
  7. Diagnosis: Immediate Ophthalmology Consult Indications
    1. Manifest (constant) deviation in any age
    2. Intermittent Exodeviation >6 months
    3. Intermittent Esodeviation >2 months
  8. Diagnosis: Pitfalls - Pseudostrabismus
    1. Esotropia may be apparent despite normal alignment
    2. Iris appears to be surrounded by different white
    3. Illusion of different amount white on each side of iris
      1. Flat nasal bridge
      2. Large epicanthal folds
    4. Differentiate from strabismus with proper testing
      1. See Strabismus signs above
    5. Refer to Ophthalmology for any question of misalignment
  9. Management: Early consultation is critical
    1. Surgical Realignment of eyes
    2. Amblyopia treated prior to realignment surgery
  10. Prognosis for congenital esotropia
    1. Repair under age 1 year
      1. Offers best chance of near-normal binocular vision
    2. Repair over age 1 year
      1. Significantly worse prognosis for binocular vision
  11. References
    1. Berson (1987) Ophthalmology Study Guide, AAO, p. 95-110
    2. Essman (1992) Am Fam Physician 46(4):1243
    3. Mills (1999) Am Fam Physician 60(3):907
    4. Simon (2001) Am Fam Physician 64(4):623

Strabismus (C0038379)

Definition (MSH)Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)
ConceptsDisease or Syndrome (T047)
ICD9378.30, 378.4, 378.40, 378.9
BasqueESTRABISMOA
DanishSkelen/strabimus
DutchStrabismus
EnglishDisorder of binocular eye movements, Heterophoria, Heterotropia, Ocular dissociation, Phoria, Phorias, Squint, Strabismus, Unspecified heterophoria, Unspecified heterotropia
FinnishKARSASTUS
FrenchStrabisme
GermanSchielen/Strabismus
Hebrewpzila
Hungariankancsalsag
ItalianStrabismo
NorwegianSKJELING/STRABISME
PortugueseEstrabismo
SpanishEstrabismo, estrabismo latente, heteroforia no especificada, heterotropía, heterotropía no especificada, heterotropia, heterotropia no especificada
SwedishSKELNING
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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