Progressive lenses described as having a short corridor and/or a high add power are classified as which design?

Prepare for the NBEO Physiological Optics Test with flashcards and multiple choice questions, each offering hints and explanations. Equip yourself for your exam!

Multiple Choice

Progressive lenses described as having a short corridor and/or a high add power are classified as which design?

Explanation:
Progressive lens designs are described by how quickly the power changes across the lens (the corridor length) and how strong the near add is. A short corridor means the progression from distance to reading power happens over a small distance, and a high add power means a steep power gradient. This combination creates a more abrupt, quickly changing lens surface and often more peripheral distortion, which is characteristic of a hard design. Soft designs use a longer corridor with a smoother transition, making adaptation easier and reducing peripheral distortion, while medium sits between. Ultra isn’t defined by this specific short corridor/high add pairing. So the described features align with a hard design.

Progressive lens designs are described by how quickly the power changes across the lens (the corridor length) and how strong the near add is. A short corridor means the progression from distance to reading power happens over a small distance, and a high add power means a steep power gradient. This combination creates a more abrupt, quickly changing lens surface and often more peripheral distortion, which is characteristic of a hard design. Soft designs use a longer corridor with a smoother transition, making adaptation easier and reducing peripheral distortion, while medium sits between. Ultra isn’t defined by this specific short corridor/high add pairing. So the described features align with a hard design.

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