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Hypertropia in unilateral isolated abducens palsy
Matthew S Pihlblad1, Joseph L Demer2
1Department of Ophthalmology, SteinEye Institute, UCLA, Los Angeles, California.
Summary
Hypertropia is common in abducens nerve palsy, affecting 19-57% of patients. This finding does not indicate other serious neurological conditions, suggesting isolated abducens nerve palsy is a primary cause.
Area of Science:
- Ophthalmology
- Neuro-ophthalmology
- Strabismus
Background:
- Abducens nerve palsy (sixth cranial nerve palsy) can lead to significant visual disturbances.
- Hypertropia, an upward deviation of one eye, is a common sequela of various ocular motility disorders.
Purpose of the Study:
- To determine the frequency and characteristics of hypertropia in patients with isolated abducens nerve palsy.
- To differentiate hypertropia associated with abducens nerve palsy from other causes of vertical strabismus.
Main Methods:
- Retrospective review of patients with unilateral, isolated, previously unoperated abducens nerve palsy.
- Binocular alignment assessed using cover testing, Krimsky measurement, and Hess screen testing.
- Exclusion of patients with other cranial nerve palsies, orbital disease, or prior strabismus surgery.
Main Results:
- Hypertropia was detected in 19% of patients via cover/Krimsky testing and 57% via Hess screen testing.
- Mean hypertropia measurements ranged from 5.0Δ to 5.8Δ.
- In partial abducens palsy, 61% of patients exhibited ipsilesional hypertropia.
Conclusions:
- Small-angle hypertropia is a frequent finding in isolated, unilateral abducens nerve palsy.
- The presence of hypertropia in this context does not necessitate the diagnosis of multiple cranial neuropathies or skew deviation.
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