Progressivgläsern

Progressivgläsern, also known as progressive lenses or multifocal lenses, are ophthalmic lenses that provide correction for presbyopia, a condition where the eye's natural lens loses its ability to focus on near objects. Unlike bifocal or trifocal lenses, which have distinct lines separating different focal powers, progressive lenses offer a seamless transition between a distance correction at the top of the lens, an intermediate correction in the middle, and a near correction at the bottom. This gradual change in prescription allows the wearer to see clearly at all distances without the visual interruption of a line.

The design of progressive lenses involves complex optical engineering. The distance prescription is typically in the upper portion of the lens. As the wearer looks downwards through the lens, the prescription gradually increases to accommodate for intermediate and then near vision. The precise power progression and the width of the different zones are tailored to individual needs and can vary between lens designs. Side effects, such as peripheral distortion or a "swim" effect, can occur, especially during the initial adaptation period, as the lens surface is curved to achieve the progressive power change. Lens manufacturers offer various designs, some aiming to minimize these distortions and optimize the viewing areas. Successful adaptation to progressive lenses usually requires a period of adjustment, during which the wearer learns to move their head and eyes to find the correct focal point for the desired viewing distance.