Near Addition as a Corridor-Positioning Variable in Progressive Addition Lenses: A Functional Approach to Intermediate Zone Accessibility in High Myopic Presbyopes

This paper presents a functional perspective on the role of near addition in progressive addition lens (PAL) performance, with particular emphasis on intermediate-zone accessibility in high myopic presbyopes. It proposes that near addition should not be viewed solely as a measure of near magnification or accommodative support, but also as a variable influencing the vertical positioning and functional accessibility of intermediate viewing zones within the progressive lens corridor. The paper explores how add selection may influence habitual gaze behaviour, intermediate visual access, and the functional experience of progressive lens wearers. It highlights the distinction between optical power progression and functional accessibility, suggesting that some progressive lens difficulties may arise not simply from corridor design, but from the interaction between addition power, corridor geometry, and the wearer’s habitual visual behaviour. This framework offers a functional approach to understanding and evaluating intermediate-zone accessibility, particularly in high myopic presbyopes.