An objective method of measuring the longitudinal chromatic aberration of the eye by carrying out retinoscopy through various coloured filters (usually a red and a green filter). However, it is necessary to use a retinoscope source of high luminance (e.g. halogen). The difference in the retinoscopic value obtained with the two coloured filters represents the longitudinal chromatic aberration of the eye between these two dominant wavelengths.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann