| 释义 |
spherical equivalent equivalent, sphericalA spherical power whose focal point coincides with the circle of least confusion of a spherocylindrical lens. Hence, the spherical equivalent of a prescription is equal to the algebraic sum of the value of the sphere and half the cylindrical value, i.e. sphere + cylinder/2. Example: the spherical equivalent of the prescription −3 D sphere −2 D cylinder axis 180º is equal to −4 D. |