Translation

肉眼 / 裸眼

Meaning

Vision achieved without the assistance of magnifying tools like glasses, telescopes, or microscopes.

Examples

• The comet was visible to the bare eyes on a clear, dark night.
  晴れた暗い夜には、彗星が肉眼で見えた。
• Scientists discovered the tiny fracture in the metal beam using a microscope, as it was invisible to the bare eyes.
  肉眼では見えなかったため、科学者たちは顕微鏡を使って金属梁の小さな亀裂を発見した。