Confocal microscopy is based on spatial filtering. The word confocal refers to two pinhole or two slit apertures that are in conjugate planes. In 1951, Hiroto Naora invented a confocal microscope. The invention of the confocal microscope is usually attributed to Professor Marvin Minsky who claims to have invented his confocal microscope in 1955. Mojmír Petráň invented the Confocal Spinning Disk Microscope based on a Nipkow disk in 1966. In 1996, Akira Ichihara and coworkers at Yokogawa Research Institute Corporation published an article, High-speed confocal fluorescence microscopy, using a Nipkow scanner with microlenses for 3-D imaging of single fluorescence molecule in real time, which demonstrated the utility of the Yokogawa microlens Nipkow disk confocal microscope operating in the fluorescence mode on biological specimens. Examples of applications of confocal microscopes to ophthalmology and dermatology are presented.