Our eyes are attuned to visible light, which has wavelengths in the neighborhood of 0.0000005 meters. That's small enough that we usually don't need to worry about the wavelength-resolution problem since we don't look at things that are 0.0000005 meters wide.

However, the wavelength of visible light is too wide to analyze anything smaller than a cell. To observe things under higher magnification, you must use waves with smaller wavelengths. That's why people turn to scanning electron microscopes when studying sub-microscopic things like viruses. However, even the best scanning electron microscope can only show a fuzzy picture of an atom.