forced duction test
A physical examination technique where the eye is manually moved to distinguish between restrictive and paralytic causes of strabismus.
Full Definition
The forced duction test is performed by grasping the conjunctiva and sclera near the limbus with forceps and attempting to move the eye in the direction of limited movement. This test differentiates mechanical restriction from muscle weakness or paralysis. Positive forced ductions indicate restrictive strabismus, often due to thyroid eye disease, orbital fractures, or fibrosis syndromes. Negative forced ductions suggest paralytic or paretic strabismus from cranial nerve palsies or muscle weakness. The test requires topical anesthesia and is typically performed in the operating room or clinic setting.
Usage
Usage note: Results should specify which extraocular muscle and direction tested, and whether restriction was complete or partial.
In Context
- "Positive forced duction test confirmed mechanical restriction of the inferior rectus muscle." — Surgical consultation note
- "The forced duction test was negative, suggesting a neurogenic rather than restrictive etiology." — Clinical examination findings