Accessory Extraocular Muscle as a Cause of Restrictive Strabismus.

Area of Science:

• Ophthalmology
• Anatomy
• Medical Imaging

Background:

• Restrictive strabismus is typically caused by various factors, but accessory extraocular muscles are rarely reported.
• Existing literature primarily consists of isolated case reports detailing this anomaly.

Observation:

• This study retrospectively analyzed 7 patients with atypical restrictive strabismus and enophthalmos.
• All patients exhibited an anomalous orbital structure identified via magnetic resonance imaging (MRI) as an accessory extraocular muscle.
• The muscle inserted onto the posterior globe near the optic nerve in the affected eye.

Findings:

• Orbital imaging (MRI/CT) is crucial for diagnosing this rare condition.
• Seven patients presented with enophthalmos, restricted eye movements, and an accessory extraocular muscle.
• Surgical correction yielded only partial improvement in one of five surgically treated patients.

Implications:

• Accessory extraocular muscles should be considered in the differential diagnosis of atypical restrictive strabismus.
• Accurate diagnosis relies on advanced orbital imaging techniques.
• This condition presents a unique challenge in surgical management and outcomes.