SightHub Optometry & Optics Glossary

A single reference for the optics, prescription and lab terms used at SightHub.
One page per term, so a search — or a shared link — lands on the exact term.

Prescription (Rx)

• ADD — Reading Addition Power
• AXIS — Cylinder Orientation (1–180°)
• BASE — Prism Direction (BU/BD/BI/BO)
• CYL — Cylinder (astigmatism correction)
• DV — Distance Vision
• NV — Near Vision
• OD — Oculus Dexter (right eye)
• OS — Oculus Sinister (left eye)
• OU — Oculus Uterque (both eyes)
• PD — Pupillary Distance (mm)
• Plano (PL) — Zero Sphere Power
• PRISM — Prismatic Power
• Rx — Prescription
• SPH — Sphere (near/far correction)
• VA — Visual Acuity (e.g. 20/20)

Refraction & conditions

• Astigmatism — Uneven Curvature Blur
• Hyperopia — Far-Sightedness
• Myopia — Near-Sightedness
• Presbyopia — Age-Related Loss of Near Focus

Lens & lab

• AR — Anti-Reflective Coating
• BF — Bifocal Lens
• CR-39 — Standard Plastic Lens Material
• DBL — Distance Between Lenses (bridge)
• ED — Effective Diameter
• FT (FT28/FT35) — Flat-Top Segment
• HC — Hard (Scratch-Resistant) Coating
• Hi-Index — Thinner Material for Strong Rx
• MBS — Minimum Blank Size
• OC — Optical Centre
• PAL — Progressive Addition Lens
• Photochromic (PGX / Transitions) — Light-Adaptive Lenses
• Poly — Polycarbonate Lens Material
• SEG Height — Multifocal Segment Position
• SV — Single-Vision Lens
• TF — Trifocal Lens
• Tint — Lens Colour Dye
• Trivex — Lightweight Impact-Resistant Material
• UV — Ultraviolet Protection

Contact lenses

• BC — Base Curve (contact lens, mm)
• DIA — Diameter (contact lens, mm)
• Dk / Dk-t — Oxygen Permeability

Employees can add and update any card. Spanish (es) terms will live beside the English ones under their own section.