Unilateral four muscle surgery for extra-large monocular exotropia

Area of Science:

• Ophthalmology
• Strabismus Surgery
• Pediatric Ophthalmology

Background:

• Recurrent exotropia is a common complication after surgery for monocular large angle constant sensory exotropia.
• Current surgical approaches typically focus on the affected eye only.
• Oblique muscle weakening may augment horizontal rectus muscle surgery by reducing abducting forces.

Purpose of the Study:

• To evaluate the efficacy of simultaneous oblique muscle weakening combined with ipsilateral horizontal rectus muscle surgery.
• To assess the outcomes for patients with constant monocular exotropia exceeding 35 prism diopters (PD).

Main Methods:

• Retrospective case series involving patients who underwent unilateral lateral rectus recession and medial rectus resection.
• Simultaneous weakening of both ipsilateral oblique muscles was performed.
• The primary outcome measure was ocular alignment in the primary position.

Main Results:

• Mean preoperative exotropia of 57.9 PD improved to 3.3 PD postoperatively (p < 0.005).
• 92% of patients achieved an exodeviation of 10 PD or less, with 58% reaching orthotropia.
• Associated vertical deviations were resolved in 2 out of 3 patients.

Conclusions:

• Weakening ipsilateral oblique muscles can enhance horizontal rectus surgery for large angle monocular exotropia.
• This combined surgical technique may reduce abducting forces.
• Oblique muscle surgery offers a potential advantage in simultaneously correcting associated vertical deviations.