ductions
Ductions are monocular eye movements, made up of adduction, abduction, elevation, depression, intorsion and extorsion.1,2 Ductions are tested by covering the fellow eye and having the patient follow a target as far as possible into each direction of gaze. The examiner watches for movement that lags or is excessive.1,3
A limited duction may come from weakness of an ocular motor nerve or muscle, or from mechanical restriction.2 The speed of the duction helps separate the two, because speed is typically reduced with an ocular motor palsy but intact with a restrictive process.2 If the examiner cannot move the anesthetized eye by pushing or pulling on the globe, the positive forced duction test suggests mechanical restriction.2
Versions can reveal a muscle weakness that ductions hide, because a patient overcomes a weak muscle more easily with a strong innervational effort during ductions than during versions.3
More detail
Ductions can be recorded as a percentage of normal excursion or on a scale from +4 to -4, where 0 is a normal duction, +4 is severe overaction and -4 means no movement past the midline.2 For the lateral rectus, -3 means the eye cannot abduct more than 22.5 degrees past the midline, -2 no more than 45 degrees, and -1 no more than 67.5 degrees.1 An apparent limitation should be confirmed with a cover test or Maddox rod, which should show the expected misalignment.2
Sources (6)
- Kanski's Clinical Ophthalmology (2024), ch. 18
- Neuro-Ophthalmology: Diagnosis and Management, ch. 2
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 12
- Rutstein, R., Daum, K. (1997). Anomalies of Binocular Vision: Diagnosis & Management, Mosby.
- Gunton, K. B. (2015). Dissociated vertical deviation: clinical features, associated abnormalities, and a new pathogenetic concept. Eye, 29(2), 213-220.
- Riordan-Eva, P., & Whitcher, J. P. (2008). Vaughan & Asbury's general ophthalmology. McGraw-Hill Medical Pub.
Reviewed October 2026