Progressive lenses are glasses designed for those with degrading eyesight. Unlike normal glasses, progressive lenses offer the wearer different types of magnifications that would require the wearer to use multiple pairs of glasses to achieve otherwise.
Progressive lenses are corrective lenses used in glasses to correct prebyopia and other common disorders. Unlike other lenses, progressive lenses contain a gradient of increasing lens power, designed to help train the wearer's eye to improve vision. The glasses start with a very weak or no gradient and gradually increase the power of the lens as it goes lower. The final magnification power of the lens is usually about 1 to 2.5 dioptres depending upon the wearer’s condition.
Progressive lenses are most commonly used by older adults. After age 40, some people find that their eyes have a harder time focusing. Even with the use of normal reading glasses some users find reading to become progressively difficult because of how weak the muscles in their eye become.
Instead of using multiple types of different focused reading glasses users can view different objects through different magnifications by tilting their head slightly so that they’re looking through a different portion of the lens. Progressive lenses also lack the distorted images that are caused by bifocal and trifocal lenses.
Some new users have trouble adjusting to the different focuses on their glasses and will often get headaches and dizzy spells while wearing their new glasses. Removing the glasses for about an hour or until the symptoms pass is the typical solution until the user is familiar with the lenses.
People who wear progressive lenses often complain about distorted images that wearers can find distracting and discomforting. Since progressive lenses have the magnification of many different lenses, viewing small spots in the lens can cause the image to blur and distort.