UCLA researchers decode muscle mechanics behind the blink

A blink of an eye looks natural and instant, but is it? Without a functional eyelid, the eye can dry, annoy and eventually lose the ability to see clearly.

Now, a group of UCLA industrial engineers and ophthalmologists has revealed new details about the muscle. Published in Proceedings of the National Academy of SciencesThe study found that the Orbicularis oculi – the muscle that controls the movement of the eyelids – conventions to complex patterns that vary depending on the action and move the eyelid to more than just a downward motion.

Researchers studied how the muscle behaves differently in different actions, such as spontaneous flashes, protective rapid closures and compressed closing movements.

“The movement of the eyelid is as complicated and more accurately controlled by the nervous system than he had previously understood,” said corresponding writer Tyler Clites, Assistant Professor of Engineering and Aerospace Engineering at the UCLA Samueli School of Engineering. “Various parts of the muscle activate in carefully timed sequences depending on what the eye does. This level of muscle control has never been recorded in the human eyelid.

In volunteer experiments, the researchers examined five different ways that close their eyes:

• Spontaneous flash: an automatic, unconscious flash that regularly occurs to keep the eye lipped
• Voluntary blink: an intentional flash, such as when one is called upon to blink in the command
• Reflexive Blink: A rapid, unintentional flash activated to protect the eye from a collision
• Softly closure: a gentle, slow -descent of eyelids, similar to the principle of sleep
• A forced closure: a deliberate compression of the eyelids closed

To record the activity in Orbicularis Oculi with high precision, an ophthalmic surgeon introduced tiny wire electrodes into the eyelid. The researchers then used a motion capture system to monitor the eyelash movement in Ultraslow. These tools allowed the group to measure the subtle differences in the movement of the eyelids, including speed, direction and part of the muscles began the action.

“People can lose the ability to blink due to stroke, tumor, infection or injury.” We know that a small electric pulse can stimulate the muscle.

With this fundamental knowledge of their manufacturing manufacturers at hand, researchers can now work to refine an original neuroproduction to help people with flash.

“Understanding the way the eyelid works is vital to the design of an accurate stimulation model for an intention as well as for diagnostic purposes,” said first author Jinyoung Kim, a UCLA doctoral engineering student and a member of the UCLA Team Research Team. “We are more than excited to bridge this gap and move on to work with patients who have facial paralysis and help improve their lives.”

Other writers, all from UCLA, include Ashley Shirriff, Jordan Cornwell and Maria Paula Quintero Mutis with ophthalmic plastic and remoderative surgery. And Ereni Delis and Sophia Wang, both undergraduate researchers in the Clites team. The Clites also have a common school appointment in the Biomedical Departments in UCLA Samueli and Orthopedic Surgery at the Geffen School of Medicine.

The research was funded by the National Institute of Eye Institute of the National Institute of Health.