Abstract
Nowadays, progressive addition lenses are widely applied to correct people’s vision disorders, but the design and machining of progressive addition lenses are still difficult. Generally, a progressive addition lens has a freeform front surface and a spherical back surface. In this article, the design of the front surface was simplified as a minimization problem of a functional, and the solution was obtained directly using a variational-difference method. After solving this problem, the description of the surface was discussed, and an evaluation method was proposed to analyze the fitting accuracy of Zernike polynomial method and B-spline interpolation method with different degrees. As a result, the progressive addition lens surface was constructed by the method with smaller fitting error. Moreover, a new generation algorithm of entrance parameters for tool path generation was put forward, which can reduce the interpolation error. The experimental results indicate that the design method was feasible and the machined surface quality was satisfactory using the proposed algorithm.
Highlights
Presbyopia affects people when they are 40 years or older.[1]
The C spindle is fixed on the platform moving along Xaxis and the tool moving along Z-axis
The front surface of the designed Progressive addition lenses (PALs) was machined without cutting fluid, and the values of BASE and ADD for the surface were 3 and 2 diopter, respectively
Summary
Presbyopia affects people when they are 40 years or older.[1] Traditional single-vision lenses can help presbyopic patients by providing good vision for near viewing. In order to see far regions clearly, people need to take off the spectacles. Progressive addition lenses (PALs) can overcome this inconvenience and are widely used in the correction of presbyopia nowadays. The far-view zone has smaller optical power than that in near-view zone, and the connection of these two view zones is achieved by intermediate zone where the change of optical power is smooth and progressive.[2] All zones have astigmatism because of the optical power distribution. A satisfied PAL design means that the variation of optical power from upper part to lower part is smooth and progressive and the astigmatism in blending zones is relatively low
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
