I Can Twist My Eye Around Its Pupil (And So Can You)

Summary by Krater

Steve Mould explains why human eyes counter-rotate when moving the head, demonstrating how cyclovergence evolved from animals with side-facing eyes to maintain both stable retinal images and depth perception.

From the video

Answers: Why do our eyes move when we move our heads?

• Human eye movement
• Cyclovergence and cycloversion
• Depth perception
• Vestibulo-ocular reflex
• Evolutionary biology of vision

What it concludes

• Eyes counter-rotate when moving the head to maintain a stable image on the retina and reduce motion blur.
• Cyclovergence helps maintain depth perception by keeping eyes in correct alignment.
• Cyclovergence is an evolutionary co-optation of the eye movement trait from ancestors with side-facing eyes.
• Combining balance information from the inner ear and visual input produces the best rotational stability for eye movement.
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