The magnitude of longitudinal chromatic aberration of the human eye between 458 and 633 nm.

The longitudinal chromatic aberration (LCA) of the human eye was determined between wavelengths 458 and 633 nm for ten observers by incorporating Argon and Helium-Neon Lasers into a Badal optometer system such that tonic (or "dark focus") resting positions of accommodation could be measured under darkroom conditions. A mean chromatic range of 1.87 D was found between 488 and 633 nm. The range increased slightly to 1.91 D when the experiment was repeated under cycloplegia on a subset of three subjects. Additional wavelengths (458 and 476 nm) for a further subset (four subjects) increased the range to 2.65 D. This magnitude of LCA would support recent predictions based on Abbe and Pulfrich refractometry analyses of the dispersion of the human crystalline lens and ocular media.