Definitions:

1. Refers to the human ability to perceive or observe something without the use of any visual aid or instrument. NOUN
   • Bacteria are too small to be seen with the naked eye.
2. Seen something using only your natural vision, unaided by optical instruments. NOUN
   • The comet was bright enough to be seen with the naked eye.

Synonyms:

• direct observation
• macroscopic view
• unaided vision