monofokaalinen

Monofokaalinen refers to a type of lens that has a single focal point. This means that when light passes through a monofocal lens, it is converged to a single point in space. This is in contrast to multifocal lenses, which have multiple focal points and are designed to correct for different distances.

In the context of eyeglasses, monofocal lenses are the most common type. They are prescribed to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. A monofocal lens for myopia will focus distant objects clearly, while a monofocal lens for hyperopia will help with near vision. For astigmatism, the lens corrects for an irregularly shaped cornea. Typically, a person wearing monofocal glasses will have one prescription for all their visual needs, whether that's seeing far away or up close, or a specific correction for distance and another for near if separate pairs of glasses are used.

Beyond eyeglasses, the concept of monofocal applies to other optical instruments as well. For example, in cameras, a monofocal lens, often referred to as a prime lens, has a fixed focal length. This means the lens cannot zoom; the photographer must physically move closer or further away from the subject to change the magnification. Prime lenses are often praised for their sharpness and wide apertures, which are beneficial in low light conditions. In microscopy, monofocal objective lenses are used to provide a sharp image at a specific magnification.