肉眼

1. Origins, structure, and basic meaning

• Structure: 肉眼 is read as にくがん and is a noun for the unaided eye or unaided vision, without a telescope, microscope, or similar instrument.
• Basic usage: Use 肉眼で確認する for the means of seeing and 肉眼では見えない for the limit of unaided vision.

2. Common pitfalls and similar expressions

• で and では
  • で marks the means of observation; では contrasts unaided vision with other methods and stresses its limitation.
• Difference from 裸眼
  • 肉眼 contrasts with optical instruments, while 裸眼 usually contrasts uncorrected eyesight with glasses or contact lenses.