Dear Editor:
We have read the article by Costea and associates; however, we believe that some discussion is required [1]. The authors review the history of the optic chiasm from antiquity to the twentieth century. It is presented that within the optic chiasm, the nervous fibers from the lower retinal quadrants loop forward into the termination of the opposite optic nerve before passing back into the optic tract (named anatomically the Wilbrand’s knee).`
Indeed, the Wilbrand’s knee appears in the majority of current textbooks of ophthalmology and neuro-ophthalmology, and damage to it was previously assumed to be responsible for junctional scotoma. However, Wilbrand’s Knee is an artifact, and does not exist in the normal primate optic chiasm [2]. Horton demonstrated that optic nerve fibers cross the optic chiasm without entering the contralateral optic nerve [3]. The Wilbrand’s knee forms in long-term after monocular enucleation, presumably from shrinkage of the optic chiasm caused by atrophy of fibers from the enucleated eye. Therefore, the anterior chiasmal syndrome occurs from combined compression of the optic chiasm and one or both optic nerves, and has a limited localizing value.
References
Costea CF, Turliuc Ş, Buzdugă C et al (2017) The history of optic chiasm from antiquity to the twentieth century. Childs Nerv Syst 33(11):1889–1898
Grzybowski A (2007) History of ophthalmology: a distinguished or extinguished field of scholarly activity? Acta Ophthalmol Scand 85(6):691–692
Horton JC (1997) Wilbrand’s knee of the primate optic chiasm is an artefact of monocular enucleation. Trans Am Ophthalmol Soc 95(4):579–609
Funding
Dr. Grzybowski reports grants, personal fees, and non-financial support from Bayer; grants and non-financial support from Novartis; non-financial support from Alcon; personal fees and non-financial support from Valeant; grants and non-financial support from Allergan; grants and non-financial support from Pfizer; and grants and financial support from Santen. Dr. Kanclerz reports non-financial support from Visim.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
No conflicting relationship exists for any author.
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Grzybowski, A., Kanclerz, P. The Wilbrand’s knee does not exist in the optic chiasm. Childs Nerv Syst 34, 2133 (2018). https://doi.org/10.1007/s00381-018-3969-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00381-018-3969-5