Design for progressive addition lenses

Progressive addition lenses design is focused on utilizing the shape of lens surface, which is not rotationally symmetric, and provides power addition. The lenses should meet power variation progressively without allowing the aberrations to attain detrimental values. The principle and e idea of designing progressive addition lenses are introduced. Several kinds of design methods are illustrated, and their advantages and drawbacks are also represented. Based on one of design methods, which the distance and near power points are determined firstly, then an umbilic line of progressive dioptric power is optimized to satisfy realistic requirements on stability of power and binocular compatibility, the form of the progressive power surface will be gotten, a progressive addition lens design that matches the particular visual needs of the patient is given out. Progressive addition lenses were manufactured with Satisloh VFT-compact machine. The lenses manufactured were measured using the Class Plus lens analyzer to provide sphere and cylinder across the surface of the lens. The results of measurement show that the lenses having a progressive power surface with a near portion and a distance portion, the near portion being of higher power than the distance portion, the form of the progressive power surface of the lens is effective to distribute surface astigmatism. In the current study, it is also shown that the optical characteristics of the different progressive addition lenses designs are significantly different from one another. The lenses designed and manufactured meet the needs. Compared with the lenses designed using Seiko software, the performance is similar with each other.