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Updated: Jun 23, 2026
05:46
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Toward an implantable functional electrical stimulation device to correct strabismus.
Federico G Velez1, Jun Isobe, David Zealear
1Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, California 90095, USA. velez@jsei.ucla.edu
Summary
Electrical stimulation can restore eye movement in cases of sixth cranial nerve palsy. This study demonstrates that stimulating the lateral rectus muscle, even when denervated, can achieve significant eye abduction.
Area of Science:
- Ophthalmology
- Neuroscience
- Biomedical Engineering
Background:
- Sixth cranial nerve palsy, or abducens nerve palsy, affects eye movement, specifically abduction.
- Complete palsy results in a loss of the eye's ability to move outward.
- Restoring abduction is crucial for binocular vision and reducing diplopia.
Purpose of the Study:
- To assess the feasibility of using electrical stimulation to reanimate the lateral rectus muscle.
- To investigate the potential for recovering eye abduction in simulated sixth nerve palsy.
Main Methods:
- Utilized a feline lateral rectus muscle model.
- Applied charge-balanced, biphasic, current-controlled electrical stimuli.
- Varied stimulation parameters (frequency, amplitude, pulse duration) and measured eye deflection.
- Simulated denervation using botulinum toxin A injections.
Main Results:
- Electrical stimulation evoked abduction in both control and chemically denervated lateral rectus muscles.
- Stimulation of denervated muscles resulted in 17 degrees of abduction.
- Stimulation amplitude was a key factor in controlling eye movement, with frequencies above 175 Hz showing limited additional benefit.
- Minimum fusion frequency remained stable after 4 weeks of chemical denervation.
Conclusions:
- Electrical stimulation is a viable method for inducing contractions in denervated lateral rectus muscles.
- Modulating stimulation amplitude is effective for controlling eye movement.
- Coordinated modulation of both frequency and amplitude is likely necessary for precise control of eye position.
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