A fluorescent microscope uses fluorescence as a detection method. Fluorescent microscopes are able to give detailed images of cell and tissue features that might not be visible using conventional light microscopy. While some cell structures fluoresce naturally, in other cases fluorochromes need to be added to the sample before imaging. In other cases, cells can be genetically modified so a protein of interest fluoresces. This allows scientists to observe where a protein of interest performs its action in a live cell. One drawback to fluorescence microscopy is that viewing the samples will cause the fluorescence to fade over time. Addition of anti-fading reagents can help reduce this effect.