bifokál

Bifokál is a term used in the field of optics and vision science to describe a type of lens or optical system that provides two distinct focal points or fields of focus. This is achieved by incorporating a prismatic element into the lens design, which splits the incoming light into two separate images, each focused at a different distance. The most common application of bifokál lenses is in eyeglasses, where they are used to correct presbyopia, a condition in which the eye loses its ability to focus on both near and distant objects.

Bifokál lenses are typically divided into two segments: the upper part, which corrects distant vision, and the lower part, which corrects near vision. The boundary between these two segments is known as the "line of demarcation" or "line of division." The position of this line can be adjusted to suit the individual's needs, depending on their specific visual requirements.

There are several types of bifokál lenses, including progressive lenses, which provide a smooth transition between the two focal points, and segmented lenses, which have a distinct line of demarcation. Bifokál lenses can be made from various materials, including plastic and glass, and can be further customized with additional features such as anti-reflective coatings and UV protection.

Bifokál lenses are widely used by individuals who experience presbyopia, as well as those who require correction for both nearsightedness and farsightedness. They offer a convenient and effective solution for managing multiple vision problems, allowing wearers to see clearly at both near and distant distances without the need for multiple pairs of glasses.