Which multifocal contact lens is usually made of rigid (GP) material with the reading portion located at the bottom?

The choice of segment bifocal contact lenses is based on their unique design, which incorporates distinct regions for distance and near vision within a single lens. These lenses are typically made from rigid gas permeable (GP) materials, giving them the ability to maintain shape and provide clear vision at varying distances.

In segment bifocal designs, the reading portion is strategically positioned at the bottom of the lens. This placement allows for comfortable and natural reading, as it aligns well with the typical gaze of someone reading or working on a close task. The upper section of the lens is formulated for distance vision, enabling users to transition smoothly between viewing far and near objects without any significant adjustment or compromise in visual acuity.

In contrast, blended bifocals and other multifocal options may not strictly follow this structure or may feature progressive designs that provide a gradient of vision correction without clear demarcation lines. Executive bifocal lenses, while also having a clear division, are generally broader in design and may not always be made from GP material. Hence, segment bifocal lenses specifically meet the criteria presented in the question regarding their construction and functional characteristics.