Constant Esotropia Flashcards
(23 cards)
What is constant exotropia?
A form of exotropia where the eye deviates outward consistently
What are the types of exotropia?
- Primary
- Secondary
- Consecutive
- Constant
- Intermittent
What is the global prevalence of exotropia?
1.23% (Govindan et al 2005)
Which gender is more affected by constant exotropia?
Female (60-70% of cases, Laughton et al 2023)
What are the risk factors for strabismus?
- Low birth weight - < 2500g
- Gestational age - < 37 weeks
- Head circumference at birth - > 37cm
What congenital abnormalities are associated with exotropia?
Exotropia is more strongly associated with congenital abnormalities (22% malformations or chromosomal abnormalities)
What are the mechanical factors contributing to exotropia?
- Shape and angle of the orbits
- Wider inter-pupillary distance (IPD)
- Less overlap of visual fields (VF)
Fill in the blank: Excessive divergence or insufficient convergence can result in _______ deviation.
exo
When does constant exotropia typically present?
Around 18 months to 2 years
What is infantile exotropia?
Constant exotropia from birth, often associated with a congenital abnormality
What factors affect the prognosis for exotropia?
- Earlier onset leads to less chance of gaining functional outcome
- Longer duration results in less favorable outcomes
What is the aim of managing primary constant exotropia?
- Restore binocular single vision (BSV)
- Improve alignment if non-functional
What investigations are important for primary constant exotropia?
- Visual acuity (VA) for amblyopia
- Cover test (CT) for constant exotropia
- Ocular motility (OM) assessment
What is the significance of the amblyopia and strabismus questionnaire (AS20)?
It assesses psychosocial impact and improvement post-operatively
What surgical procedures are common for correcting constant exotropia?
- Lateral rectus recession
- Medial rectus resection
What is the risk associated with strabismus surgery?
Anterior segment ischemia, a rare but serious complication
Fill in the blank: If no potential for BSV, aim for slight _______.
overcorrection
What therapeutic use does botulinum toxin have in treating exotropia?
It is injected into the appropriate muscle to help with alignment
What is the purpose of the post-operative diplopia test?
To assess the risk of diplopia after surgery
What are some potential outcomes of the post-op diplopia test?
- Suppresses to certain prism diopters (PD)
- Homonymous diplopia with increasing prisms
- No diplopia with correcting prisms
What is the aim of treatment for amblyopia in children under 8 years?
To treat amblyopia effectively
What role do exercises play in the management of primary constant exotropia?
They are used to correct the angle in functional cases
What is the recommended reading for the topic of constant exotropia?
- Ansons & Davis 4th edition, pages 344-379
- Von Noorden & Campos, pages 356-372
