# ESTABLISHING THE NEUROPHYSIOLOGICAL BASIS FOR RESTORATION OF NATURAL BLINK

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2024 · $213,801

## Abstract

PROJECT SUMMARY
Facial paralysis from stroke or other neurological disorders often causes loss of the eye-blink reflex, leading to
pain and visual disability. Eyelid dysfunction leaves the eye chronically exposed, which is not only painful, but is
fundamentally incompatible with functional vision. Further, because eyelid movement plays a critical role in facial
expression and human communication, loss of natural eyelid motion can also have negative social and cultural
implications. Unfortunately, current surgical management strategies have major limitations in both functionality
and appearance. In theory, dynamic natural blink restoration via a facial neuroprosthesis would be an ideal
solution; unfortunately, this ideal has proven elusive, due in large part to a lack of knowledge regarding the
neurophysiological mechanisms that enable eyelid function. There is a critical need for neuroprostheses that
reproduce functionally complete and aesthetically natural eye closure, blink, and other behaviors. In response to
this need, our long-term goal is to advance a novel class of neuroprostheses that are informed by a deep
understanding of the fundamental neuromechanics of the muscle that controls the eyelid. To achieve our long-
term goal, we will first carry out fundamental neuroscientific studies to establish the currently-unknown
mechanisms that link segmental muscle activation to eyelid motion and function. The innovation of this work lies
in our ability to measure intramuscular activation and three-dimensional eyelid kinematics with unprecedented
precision and resolution. This sets our work apart from all other prior research into eyelid function, and will allow
us to develop the first predictive dynamic neuromuscular model of the eyelid. In the present work, our objective
is to study the neurophysiology of how activation sequences and intensities produce blink and other eyelid
behaviors under both healthy and pathological activation. We will accomplish this by first studying eyelid function
in persons without paralysis during a range of eyelid behaviors, including spontaneous blink, reflexive blink, and
forced closure. As the participants perform these behaviors, we will record high-resolution intramuscular EMG
from multiple points within and around the eyelid, while simultaneously tracking the three-dimensional motion of
several points along the eyelid margin in high definition. We will use these data to implement a mechanistic
neuromuscular model of the eyelid musculature, which can then inform where and when stimulation from future
neuroprostheses should be delivered. We will then repeat these experiments in a group of persons with partial
facial paralysis, to study the mechanisms by which eyelid function can be compromised. Upon completion of this
work, we expect to have established the mechanistic basis for model-informed facial neuroprostheses that
restore natural blink. These results are expected to provide the foundation for development an...

## Key facts

- **NIH application ID:** 10953294
- **Project number:** 1R21EY036680-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** Tyler R Clites
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $213,801
- **Award type:** 1
- **Project period:** 2024-09-01 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10953294

## Citation

> US National Institutes of Health, RePORTER application 10953294, ESTABLISHING THE NEUROPHYSIOLOGICAL BASIS FOR RESTORATION OF NATURAL BLINK (1R21EY036680-01). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10953294. Licensed CC0.

---

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