Early Onset Sixth-Nerve Palsy with Eccentric Fixation.

Area of Science:

• Ophthalmology
• Pediatric Neurology
• Strabismology

Background:

• Early onset sixth-nerve palsy is a rare condition affecting eye alignment in children.
• Congenital sixth-nerve palsy can lead to significant visual deficits, including strabismus and amblyopia.
• Eccentric fixation is a common visual adaptation in cases of early onset paralytic strabismus.

Observation:

• Four cases of early onset sixth-nerve palsy were reviewed, with three congenital.
• All patients presented with esotropia and eccentric fixation, often masked until after surgery.
• MRI revealed abnormalities in three out of four patients.

Findings:

• Surgical interventions included vertical muscle transposition with Botulinum Toxin A (BTXA) and medial rectus recession with lateral rectus resection.
• Significant reductions in esotropia were observed postoperatively.
• Eccentric fixation persisted in some cases, suggesting a complex etiology.

Implications:

• Congenital sixth-nerve palsy may impair cross-fixation, leading to eccentric fixation.
• Reverse occlusion was ineffective in correcting eccentric fixation.
• Early surgical management is crucial to mitigate the development of eccentric fixation and associated visual impairments.