secondary angle of deviation
In incomitant strabismus, the secondary angle of deviation is the angle of misalignment of the sound eye when the paretic eye is made to fixate. It is larger than the primary deviation.
Holding fixation with the paretic eye demands extra innervation to the weak muscle. By Hering’s law the same extra drive reaches that muscle’s yoke in the sound eye, which overshoots.
Sources (5)
- Ansons, A.M. and Davis, H. eds. 2014. Diagnosis and management of ocular motility disorders. 4th ed. Oxford: Wiley-Blackwell.
- Noorden, G.K. and Campos, E.C. 2002. Binocular vision and ocular motility: theory and management of strabismus. 6th ed. St. Louis: Mosby.
- Rutstein, R. and Daum, K. 1997. Anomalies of Binocular Vision: Diagnosis & Management. St. Louis: Mosby.
- Rowe, F.J. 2012. Clinical orthoptics. 3rd ed. Oxford: Wiley-Blackwell.
- Von Noorden, G.K. and Campos, E.C. 2002. Binocular vision and ocular motility: theory and management of strabismus. 6th ed. St. Louis: Mosby.
Reviewed October 2026
Related terms
Nearby in the glossary
- saccades
- saccadic velocity
- second-degree fusion
- secondary angle of deviation
- secondary position
- sensory fusion
- sensory strabismus