power 4dPower of the lens (P) = 4 D. Refractive Index (r) = 1.5. To Find: The radius of curvature. Calculations: The following equation determines a lens's power: where P is the power ofAFL's OPM5 and OPM4 Optical Power Meters for accurate fiber optic testing. Featuring Wave ID, rugged desn, and compatibility with various networks. ... -4D (Filtered-InGaAs) for hh