Imaging of the superior rectus in superior rectus overaction after retrobulbar anesthesia.

OBJECTIVE

Vertical diplopia after cataract surgery caused by an overaction of an extraocular muscle is more common when the superior rectus muscle is involved, whereas contracture is more common when the inferior rectus muscle is involved. However, no documented imaging has been presented. The aim of this report was to study the superior rectus in such a patient with magnetic resonance imaging (MRI).

DESIGN

Observational case report.

METHODS

Ophthalmologic examination and thin-sectioned MRI across the superior rectus muscle were performed in a patient with superior rectus overaction after cataract surgery.

MAIN OUTCOME MEASURES: Ocular alignment, ocular movement, and the superior rectus muscle on MRI.

RESULTS

Magnetic resonance imaging disclosed focal thickening of the superior rectus muscle near the orbital apex in a patient who showed superior rectus overaction after retrobulbar anesthesia for cataract extraction.

CONCLUSIONS

The focal thickening of the superior rectus muscle in this patient is consistent with the theory that segmental contracture leads to overactive muscles after retrobulbar anesthesia.