Situational restriction: Using your physical exam to differentiate pulley abnormalities from other vertical deviations secondary to restrictive conditions

The description of the orbital pulley system has changed the way we understand eye movements and ocular motility disorders. The presence of abnormalities in the orbital pulley system can complicate the assessment of vertical restrictive conditions. The standard tests for restriction are reviewed. These include version and duction testing, assessing saccades, differential intraocular pressure measurements, forced duction testing, and forced generation testing. We introduce the concept of situational restriction and how to look for it during your physical exam. Situational restriction is a limitation of ocular rotation that is dependent on the path that is taken to try to arrive at a tertiary position of ocular rotation. Specifi cally, it shows noncommutative movement that breaks Listing's Law. The presence of situational restriction denotes that a pulley abnormality is present.