Question

Positive forced duction test is seen in?

• A. Extraocular muscle palsy
• B. Mechanical restriction of ocular movement
• C. Concomitant squint
• D. None

Hint:

Resistance on passive rotation means something is physically tethering the eye.

Answer 1

The Correct Option is B

Step 1: In the forced duction test the examiner grasps the globe with forceps and passively rotates the eye to check whether something is physically holding it back.

Step 2: A POSITIVE (abnormal) test means resistance is felt during passive rotation. The eye cannot be moved because a tethered, fibrosed or entrapped muscle or band is restricting it. This is the picture of mechanical restriction, for example thyroid eye disease or an orbital floor (blow-out) fracture with inferior rectus entrapment.

Step 3: A NEGATIVE (normal) test means the globe rotates freely with no resistance. The eye does not move on its own because the muscle is weak or paralysed, that is, an extraocular muscle palsy. The muscle is intact mechanically, only its power is lost.

Step 4: Therefore mechanical restriction gives the positive test. Muscle palsy gives a negative test, and a concomitant squint has full movements, so the answer is mechanical restriction of ocular movement.