Which lens type is primarily made of rigid material but features a reading portion?

The correct answer is segment bifocal. This lens type is specifically designed with two distinct optical zones: one for distance vision and a separate portion for near vision, typically used for reading. The reading portion is embedded within the rigid material of the lens, allowing the wearer to transition between seeing objects at varying distances without changing glasses.

Segment bifocals are particularly beneficial for individuals who require assistance with near vision tasks, like reading, while still needing to see clearly at distance. The rigid nature of the material used in these lenses provides durability and can also offer sharper vision compared to softer materials.

While other lens types may serve specific purposes, they do not combine a distinct reading segment within a rigid structure like a segment bifocal does. This makes segment bifocal lenses uniquely valuable for those with presbyopia, allowing for clear vision across different ranges effectively.