Each individual progressive lens is available in either a Standard or Short corridor design or "corridor."
Lens corridor
A lens corridor, also known as the "corridor length" or "progressive corridor," refers to the middle portion of a progressive lens where the power changes gradually from the distance prescription to the reading or near prescription.
The corridor is the area that allows for a seamless transition between different prescriptions, accommodating the wearer's needs for clear vision at various distances. The length and width of the lens corridor can vary depending on the design of the progressive lens. A longer corridor generally provides a larger area for intermediate vision, making it suitable for tasks such as computer work. On the other hand, a shorter corridor might be preferred for smaller frames or for individuals who prioritize a larger reading zone.
Standard corridor
The standard corridor offers a larger corridor and a more seamless transition between the different vision areas of the lens. This makes the lens more optimized for the wearer by offering easier use and adaptability.
Short corridor
The shorter corridor is for smaller frames that generally have less than a 30-millimeter lens height. A short corridor will have a shorter corridor for the progressive transition, which may be less optimized. Therefore, opting for a higher-quality progressive lens is advisable to improve the corridor transition in a short corridor lens. A short corridor is suitable for individuals who prefer smaller eyeglass frames.
Variable design corridor
Freeform digital lenses are only available as variable design corridors. Variable design corridors prioritize the quality of the distance and intermediate area by optimizing the lens based on the specifications of the Rx, frame measurements, and seg height. A front and backside digital lens (Freeform) must be selected to get a variable design corridor. Otherwise, non-freeform lenses will be fixed-design corridors, which means there's more focus on the reading location in relationship to the pupil, much like a traditional flat-top lens.