The state of accommodation during the measurement of axial chromatic aberration of the eye.

The axial chromatic aberration of the eye was determined as in previous studies by finding the lens required to eliminate or minimize blur of the fixation target when it is illuminated by a series of monochromatic sources. Objective measurement of the refraction of the eyes during this procedure showed that accommodation remained constant throughout. Hence, the conclusion that the accommodative state does not in this case respond automatically to changes in the vergence of light falling in the retinal plane. It is suggested that some other stimulus, perhaps perceived distance, predominates. Further, the least amount of plus lens required to blur a near target was about the same for white and red but much less for blue. This substantiates an earlier finding that the eye accommodates for near only sufficiently to place the blue end of the chromatic interval on the retina.