Optical or light microscopes are fundamental tools in microscopy that utilize visible or ultraviolet light to produce an image, typically achieving magnifications up to approximately ${}1000\times$. They come in two primary configurations: a simple microscope passes light through just one lens, a design notably used by Antonie van Leeuwenhoek; whereas a compound microscope is more sophisticated, passing light through two or more sets of lenses in a series to achieve greater magnification. Bacteria, whether living or fixed to a slide, may be viewed under these microscopes to indicate shape, motility, arrangement, and size. However, due to the absence of inherent contrast in standard optical microscopes, finer internal details often cannot be examined without additional techniques. This limitation has led to the use of various advanced light microscope types—such as brightfield, darkfield, phase-contrast, fluorescence, and confocal microscopes—to enhance contrast and resolution for specific applications.