Visibility Vol 15 Issue 2, 2021

Magnifiers can be specified by magnification (M) or equivalent power (Fe). When comparing these two, Fe is the only independent and constant descriptor and therefore preferred in low vision practice. Yet, Fe in high plus lenses cannot be easily nor reliably measured with a clinical instrument, such as a lensometer. This study looks for the shortest possible distance under which unknown high plus lenses/magnifiers can be measured and still yield clinically acceptable Fe values.

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