How is the relationship between lens diameter and base curve expressed in terms of change?

The relationship between lens diameter and base curve is fundamentally established in the practice of optical dispersion and lens design. As the diameter of a lens increases, the base curve becomes flatter due to the principles of lens geometry. Specifically, the correct expression is that every 1mm increase in diameter corresponds to a 0.50 diopter (D) change in the base curve.

In optical terms, this relationship is significant for the optical performance of lenses, especially in ensuring that the lenses maintain their focal properties and visual clarity. A flatter base curve allows for more light to pass through without excessive distortion, which is crucial for vision correction.

The other options either misrepresent the relationship or suggest it does not exist, which is not the case. Understanding this proportional relationship helps practitioners make informed decisions about lens fitting and design, ultimately affecting patient comfort and vision quality.