# Brainstem Saccade Circuitry in Strabismus

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2022 · $436,472

## Abstract

ABSTRACT
 When navigating a complex, three dimensional environment primates, including humans, must constantly
move their eyes to ensure that objects of interest activate the foveae of both eyes. For children with infantile
strabismus syndrome the eyes are chronically misaligned, which makes normal binocular vision impossible.
Persistence of this condition can lead to lasting impairments of visual function, including amblyopia, and
impaired depth perception. Oculomotor abnormalities include a lack of disparity vergence, saccade
disconjugacy, latent nystagmus, and a nasalward bias of smooth pursuit gain. Existing treatments are
successful in some patients but, in others, improvements in eye alignment prove to be transient. Monkeys with
strabismus experimentally induced in infancy show visual and oculomotor abnormalities that closely match
those found in human children. In recent years, work with these nonhuman primate models has provided
compelling evidence that prolonged disturbance of binocular vision in infancy alters the development of neural
circuits serving vision and eye movements. Over the past several years we have found clear evidence of
abnormalities affecting several brainstem oculomotor regions, including paramedian pontine reticular
formation, abducens nucleus, supraoculomotor area, nucleus prepositus hypoglossi (NPH), and the interstitial
nucleus of Cajal (INC). In pattern strabismus, the horizontal and vertical misalignments vary with eye position
along the orthogonal axis. We have found preliminary evidence that the neural basis of pattern strabismus
involves abnormal crosstalk between brainstem pathways that produce the horizontal and vertical components
of eye movements. Our studies are guided by the overarching hypothesis that loss of binocular vision during a
sensitive period in early postnatal life leads to a cascade of abnormalities that affect both visual and
oculomotor areas of the brain. At present, however, critical brainstem oculomotor regions have not been or
only incompletely studied in strabismus, which makes it very difficult to test specific developmental etiological
hypotheses. We will use a combination of single unit recording and microstimulation to elucidate the
relationship between brainstem abnormalities and the oculomotor symptoms of infantile strabismus syndrome.

## Key facts

- **NIH application ID:** 10400106
- **Project number:** 5R01EY024248-09
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Mark M Walton
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $436,472
- **Award type:** 5
- **Project period:** 2015-01-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10400106

## Citation

> US National Institutes of Health, RePORTER application 10400106, Brainstem Saccade Circuitry in Strabismus (5R01EY024248-09). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10400106. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*