Cell Size and Scale. Some cells are visible to the unaided eye The smallest objects that the unaided human eye can see are about 0.1 mm long.
That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny. Smaller cells are easily visible under a light microscope. Hunter S. Thompson leaves voicemail for an A/V dealer - Boing Bo. Imagining the Tenth Dimension - A Book by Rob Bryanton.