GLOSSARY N–Z

Still fluent. Keep going.

**Nose pads** — The adjustable cushions on metal frames that carry the weight on your nose. **OD / OS** — Prescription shorthand: OD is your right eye, OS your left. Latin, obviously. **Pantoscopic tilt** — The slight forward tilt of the frame front, tuned so lenses sit at the right angle. **PD** — Pupillary distance: the millimeters between your pupils. Get it right or nothing else matters. **Photochromic** — Lenses that darken in sunlight and clear indoors. Transitions GEN S is the famous one. **Polarized** — A filter that kills horizontal glare off water, roads, and hoods. Non-negotiable for drivers. **Polycarbonate** — Impact-resistant lens plastic. The default for kids and sport. **Progressive** — A no-line multifocal: distance to reading in one smooth gradient. **Rimless** — Lenses mounted directly to temples and bridge, no frame around them. Maximum disappearing act. **Rx** — Shorthand for prescription. Your lenses, your numbers. **Saddle bridge** — A wide bridge that distributes weight across the nose. Comfort-first design. **Temple** — The arm that runs to your ear. Holds the hinge's other half. **Trivex** — Light, strong lens material like polycarbonate, with sharper optics. **UV protection** — Blocking ultraviolet light. Non-negotiable in any lens worth wearing. **Vertex distance** — The gap between your lens and your eye. Small number, big optical consequences.