suppression
Suppression is the active central inhibition of the disparate and confusing images that arise from the retina of the deviated eye.1 When fusion is not possible in a child, suppression develops to eliminate double vision. Suppression occurs only with both eyes open, because closing one eye already removes the diplopia.1 Most electrophysiologic and psychophysical evidence places the seat of suppression in the visual cortex.1
Suppression of essentially the whole retina of one eye is rare and occurs mainly in alternating exotropia. In most strabismic patients suppression is regional, covering the fovea of the deviated eye and the peripheral area of that eye that receives the image of the fixated object.1 Central suppression at the fovea overcomes confusion, and peripheral suppression overcomes diplopia.2 Physiological suppression is a separate, normal process that keeps physiological diplopia and retinal rivalry out of awareness in normal binocular vision.2
More detail
The peripheral suppression scotoma grows larger as the deviation grows larger.1 In esotropia the foveal and peripheral areas merge into one elliptical scotoma with its long axis horizontal, known as Lang's D-shaped scotoma. In exotropia the suppressed area varies, from a scotoma like the esotropic one to the whole temporal retina.2
Sources (8)
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 13
- Eperjesi and Rundström, Practical Binocular Vision Assessment, ch. 7
- American Academy of Ophthalmology. 2019. Amblyopia Preferred Practice Pattern. San Francisco: American Academy of Ophthalmology.
- Levi, D.M., Knill, D.C. and Bavelier, D. 2015. Stereopsis and amblyopia: a mini-review. Vision Research, 114, pp.17-30.
- 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.
- Von Noorden, G.K. and Campos, E.C. 2002. Binocular vision and ocular motility: theory and management of strabismus. 6th ed. St. Louis: Mosby.
- Wong, A.M. 2012. New concepts concerning the neural mechanisms of amblyopia and their clinical implications. Canadian Journal of Ophthalmology, 47(5), pp.399-409.
Reviewed October 2026