Match spectacle frame dimensions (eye size, bridge, BVD) to the wearer's pupillary distance.
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Geometric centre distance | GCD = lens width A + bridge width B | ISO 8624:2011, Ophthalmic optics - Spectacle frames - Measuring system and terminology |
| Decentration | Decentration = ( GCD - PD ) / 2, used to align the optical centre with the pupil | ISO 8624:2011, Ophthalmic optics - Spectacle frames - Measuring system and terminology |
| Alignment principle | The optical centre should coincide with the pupil to avoid unwanted prismatic effect | ISO 8624:2011, Ophthalmic optics - Spectacle frames - Measuring system and terminology |
| Prismatic effect | Prentice's rule: P = c · F; larger decentration or power gives more prism | Prentice CF (1886), On the prismatic effect of decentred lenses |
根据镜圈宽度、鼻梁宽度与瞳距，计算单眼移心量与所需最小镜片直径，辅助镜框选型与加工。
镜框尺寸与瞳距计算器，根据镜圈宽度、鼻梁宽度和瞳距计算移心量与最小镜片直径。。医疗专业工具，基于权威医学标准，仅供参考。