infraduction
Infraduction is downward rotation of one eye, a duction also called depression.1 Ductions are tested by having the patient direct gaze into the cardinal fields, and the examiner notes both the extent and the speed of each movement.1
The inferior rectus has depression as its primary action and acts purely as a depressor when the globe is abducted 23°.2 The superior oblique depresses as a secondary action and can act only as a depressor with the globe adducted 51°, so superior oblique weakness shows mainly as failure of depression in adduction.2 The third (oculomotor) nerve supplies the inferior rectus, and the fourth (trochlear) nerve supplies the superior oblique.3
A limited infraduction can come from a palsy or from restriction.1 Duction speed is typically reduced with an ocular motor palsy but intact with a restrictive process, and a cover test or Maddox rod should confirm the expected misalignment.1
Sources (7)
- Neuro-Ophthalmology: Diagnosis and Management, ch. 2
- Kanski's Clinical Ophthalmology (2024), ch. 18
- Pickwell's Binocular Vision Anomalies, ch. 17
- 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.
- Kushner, B. J. (2017). Diagnosis and treatment of diplopia. In Pediatric Ophthalmology and Strabismus (pp. 1023-1046). Springer, Berlin, Heidelberg.
Reviewed October 2026