Which type of PD measurement is taken for fitting a progressive lens?

For fitting a progressive lens, the correct measurement type is monocular distance. This is because progressive lenses require precise measurements for each eye to ensure that the lens's multifocal zones align correctly with the wearer's visual needs. Monocular distance measurements are taken individually for each eye, allowing for the proper placement of the distance, intermediate, and near vision zones tailored to where the wearer's pupils are positioned. Proper monocular measurements contribute significantly to the overall comfort and effectiveness of the progressive lenses, as they help create a seamless transition between different vision zones.

Other measurement types, such as binocular distance or full distance, would not account for individual eye differences and might lead to misalignment or discomfort in wear. Monocular near measurements focus on reading and close-up tasks but do not provide the necessary data for the distance vision aspect that progressive lenses need to accommodate properly.