NBEO Physiological Optics Practice Test

In progressive lenses, the fit and feel for the wearer are heavily influenced by how the power changes from distance to near. A long corridor with a relatively low add power is characteristic of soft design. The long corridor means the power shifts gradually over a wide area, which smooths out the peripheral changes and reduces distortion and image jump as you move your eyes and head. The lower add power keeps the near portion from being overly strong, further easing adaptation and comfort. Hard designs, by contrast, use shorter corridors and higher adds, which can produce more abrupt changes and more peripheral distortion, making adaptation tougher. Compact designs tend to have even shorter corridors with the near zone placed more aggressively. So SAMPLEthe description of a long corridor and/or low add aligns with soft design.