Purpose. The main goal of this work is to show the principles, design, and performance of a modified point diffraction interferometer (PDI) for evaluating the local higher-order aberrations of progressive addition lenses (PALs). Because aberrations have different impacts in visual perception, we propose a device to provide a customized solution with the best permissible amounts and combinations of aberrations for improving a subject's vision. Methods. A PDI has been adapted to measure local high-order aberrations in PALs. Results. High-order aberrations in three different PALs within four relevant circular regions of interest (ROIs) with a radius ranging from 0.4 to 2.4 mm were measured with an accuracy of /10 within the ROI using the tailored PDI. The interferometer also allows for easily choosing the position and number of the ROIs. Conclusions. The interferometric device is compact, robust, and accurate. The operational principle is very simple, and it provides the local high-order aberrations directly without adding additional parts to the interferometer. As expected, the amount of high-order aberrations depends on the chosen ROI of the PAL; the corridor is the more critical region.We found, in accordance with the literature, that, in the corridor, second- and third-order aberrations are dominant and spherical aberration is negligible.
- Local high-order aberration
- Point diffraction interferometer
- Progressive addition lenses
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