An optical measurement system method for measuring a characteristic of a subject's eye use a probe beam having an infrared wavelength in the infrared spectrum to measure a refraction of the subject's eye at the infrared wavelength； capture at least two different Purkinje images at two different corresponding wavelengths from at least one surface of the lens of the subject's eye； determine from the at least two different Purkinje images a value for at least one parameter of the subject's eye； use the value of the at least one parameter to determine a customized chromatic adjustment factor for the subject's eye； and correct the measured refraction of the subject's eye at the infrared wavelength with the customized chromatic adjustment factor to determine a refraction of the subject's eye at a visible wavelength in the visible spectrum.
