Surgical exploration in persistent inferior oblique overactions.

Area of Science:

• Ophthalmology
• Strabismus Surgery
• Oculomotor Muscle Physiology

Background:

• Persistent inferior oblique (IO) overaction can occur after surgical disinsertion.
• Understanding the causes of this complication is crucial for surgical success.

Purpose of the Study:

• To investigate the causes of persistent inferior oblique (IO) overactions following disinsertion procedures.
• To identify factors contributing to IO overaction recurrence after strabismus surgery.

Main Methods:

• Retrospective analysis of surgical findings in nine eyes of eight patients requiring secondary surgery for persistent IO overaction.
• Detailed examination of IO muscle status, including retraction, scleral reattachment, and inadvertent inferior rectus disinsertion.
• Surgical technique involved isolating and dissecting IO muscle terminals, performing myectomy, and cauterization to prevent scleral contact.

Main Results:

• Persistent IO overactions were successfully resolved in all treated cases.
• No recurrence of IO overaction was observed during a follow-up period ranging from 4 months to 6 years.

Conclusions:

• Insufficient retraction of the inferior oblique (IO) muscle from the subtenon's space is a primary cause of persistent overaction post-disinsertion.
• Complete dissection of the IO muscle from all fascial attachments and ensuring its proximal terminal is fully outside the subtenon's space are key to prevention and management.