Change Language German
General Information
- 2/3 of infants exhibit mild exotropia in the first months of life
Congenital Exotropia
- Rare
- Often present at birth
- Findings: normal refraction, large and constant angle of strabismus (usually > 35 prism diopters), amblyopia is rare
- Associations:
- Dissociated vertical deviation (DVD)
- Inferior or superior oblique muscle overaction
- May spontaneously regress within 6 months; otherwise, surgery is indicated
Divergence Excess
- Exodeviation at least 10 prism diopters greater for distance than near
Convergence Insufficiency
- Typically seen in individuals with excessive near vision demands, e.g., students
- Findings: reduced near point of convergence, independent of any heterophoria
- Treatment: orthoptic exercises to normalise the near point and maximise fusion amplitudes
- If not regressing within a few weeks, consider base-in prisms
Convergence Paralysis
- Occurs in the context of Dorsal Midbrain Syndrome (Parinaud Syndrome)
- Normal adduction and accommodation
- Exotropia and diplopia during attempts at near fixation
- Treatment: base-in prisms
Decompensated Exophoria
- Diagnosed using alternating cover test
- Causes
- fatigue, sedatives, alcohol
- serious illnesses
- Asthenopic symptoms with prolonged near work
- Treatment indicated for significant asthenopic symptoms or progression to intermittent exotropia
Intermittent Exotropia
- Most common form of exotropia
- Usually starts before age 4
- Often involves squinting in bright light
- Suppression only in exo-position, amblyopia is rare
- Often presents around age 2 with exophoria that becomes exotropia during visual inattention, bright light, fatigue, or illness
- Classification:
- Exotropia for distance
- Exotropia for near
- Nonspecific exotropia with the same angle of strabismus for distance and near
- Therapy: glasses, consider reducing myopia correction to induce accommodative convergence, convergence training, amblyopia treatment with occlusion therapy, surgery
(Secondary) Sensory Exotropia
- Due to monocular or binocular vision deterioration from acquired lesions like cataract
Consecutive Exotropia
- Develops spontaneously in an amblyopic eye or more often after surgical correction of an esodeviation
Differential Diagnoses
- Duane Retraction Syndrome Type II
Sources
- EyeWiki Exotropia
- Kanski’s Clinical Ophthalmology: A Systematic Approach; John E Salmon MD; Elsevier; 9th Edition (2019)
- The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease; Kalla Gervasio MD, Travis Peck MD et al; Lippincott Williams&Wilkins; 8th Edition (2021)