# Biomechanical Analysis in Strabismus Surgery

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2024 · $668,209

## Abstract

We propose 3 interrelated aims to define the biomechanics of the extraocular (eye rotating) muscles and optic
nerve in health and visual disease, understand novel extraocular muscle actions that maintain binocular
alignment, and characterize mechanical effects that may contribute to glaucoma and severe myopia
(nearsightedness). We aim to improve treatment of strabismus, misalignment of visual directions of the eyes,
as well as glaucoma, a common blinding optic nerve disease; and gain insight into the cause of high axial
myopia, an eye elongation and shape distortion that has become a worldwide epidemic and major cause of
blindness. These conditions may all be related to the actions of the extraocular muscles (EOMs). We propose
the dynamic, repetitive strain due to eye movement is a common factor in several visual disorders. Aim I will
clarify superior oblique (SO) palsy, a common cause of vertical double vision often treated by strabismus
surgery. This aim will evaluates EOM function by multipositional magnetic resonance imaging to test an
alternative hypotheses that SO palsy often is not caused by EOM weakness, but instead by benign misdirection
of a cranial nerve, and may improve the way strabismus surgery on the EOMs can correct the double vision.
Aim II will characterize the dynamic way the eyeball is deformed by eye movements. Everyday eye
movements impose much greater mechanical forces on critical parts of the eye than does elevated intraocular
pressure. We will investigate by in living people the mechanical effects of fast and slow eye rotations on the
retina, optic disc, and other parts of the eye during horizontal and vertical eye rotations, using high speed
confocal scanning laser imaging and optical coherence tomography. We propose that the eye deformation,
especially during rapid eye movements ubiquitous in daily life, may accumulate over time to create repetitive
strain injury contributing to glaucoma and high myopia. Healthy children and adults will be compared with
subjects who have glaucoma or high myopia. Effects of eye movement will also be studied ex vivo by precision
3D optical imaging of fresh human eye bank specimens, with and without history of glaucoma, subjected to
mechanical tension on the optic nerve that mimic effects of the eye movements imaged in the living subjects.
Aim III will use computer simulation to model and validate the effects of mechanical strain in the eye
during eye movements. We will the measured time-dependent mechanical properties of donated, post-mortem
human eyes to develop finite element models (FEMs) using modern engineering methods for computational
simulation to predict how rapid eye movements cause time-varying mechanical strains in the optic nerve and
outer eye wall that may produce glaucoma & the ocular deformities underlying extreme myopia. Using FEMs,
we will explore in theory possible options for treatment of glaucoma and axial high myopia that might be
accomplished by scleral cross-linkin...

## Key facts

- **NIH application ID:** 10877456
- **Project number:** 2R01EY008313-34
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** JOSEPH Louis DEMER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $668,209
- **Award type:** 2
- **Project period:** 1991-01-06 → 2029-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10877456

## Citation

> US National Institutes of Health, RePORTER application 10877456, Biomechanical Analysis in Strabismus Surgery (2R01EY008313-34). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10877456. Licensed CC0.

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