Fluorescence microscopes are often used due to the generally better image quality when compared to white light microscopes. This is based on the use on ultra-violet light with its shorter wavelengths therefore allowing a better resolution.
Cross section of a bone from a racing horse:
The images on the left show the normal fluorescence images, with minimised over exposure. Normal fluorescence images cannot show the structures beneath them at the same time. In order to make the images on the right, a combination of fluoresence and phase contrast was used to obtain an image with the detailed background.