What do we know about the neurobiology of infantile-onset strabismus (IOS)? What has clinical and basic science work in humans and nonhuman primates (NHPs) revealed during the last 25 years?
Infantile-onset strabismus in humans and NHPs is a constellation (or syndrome) of ocular motor behaviors: eye misalignment; subnormal binocular fusion; latent fixation nystagmus (LN); dissociated vertical deviation; and in some, dissociated horizontal deviation. Children at greatest risk are those who suffer cerebral lesions around the time of birth. The common lesion is damage to the posterior-most fibers of the optic radiations, the binocular inputs to striate cortex.1- 3 These infants have a 30- to 60-fold greater chance of getting IOS compared with healthy infants. Similarly, in infant NHPs, the full IOS constellation is produced reliably (100%) by perturbation of inputs to visual cortex.4 No manipulation of eye muscles or brainstem pathways is needed. The severity of IOS in the NHP increases monotonically with neuroanatomic loss of cortical binocular connections.5 The binocular defect is passed forward from striate to extrastriate cortex, regions that mediate balanced gaze (middle temporal/medial superior temporal visual areas) and vergence.6,7 Infantile-onset strabismus behaviors, including LN, correlate with physiologic loss of binocular responses in these regions. These cortical regions drive brainstem gaze nuclei, most notably the midbrain nucleus of the optic tract and contiguous nuclei of the accessory optic system (AOS).8 The major visual drive in NHPs to brainstem gaze neurons is descending and cortical, not direct from the retina or subcortical. Taken together, the hunt for the perpetrator of IOS points upstairs to the cortex not downstairs to the brainstem.
Thank you for submitting a comment on this article. It will be reviewed by JAMA Ophthalmology editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 3
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.