Kr. Aggarwala et al., ACCOMMODATION TO MONOCHROMATIC AND WHITE-LIGHT TARGETS, Investigative ophthalmology & visual science, 36(13), 1995, pp. 2695-2705
Purpose, The objective of the current study was to compare accommodati
on to targets illuminated with monochromatic light from different regi
ons of the visible spectrum with accommodation to white-light targets.
Methods, One of 10 narrow-band interference filters (430, 450, 470, 5
00, 530, 550, 570, 590, 630, and 670 nm) was used to produce monochrom
atic light from a tungsten-halogen source to illuminate a Maltese cros
s-target in Maxwellian view. Luminance of each monochromatic light was
matched by minimum border photometry against a standard white light (
3000 K) that was maintained at 200 cd/m(2). Chromatic difference of fo
cus of the eye was minimized for all monochromatic targets by the use
of an achromatizing lens. A white-light target also was used, and the
subject's eye was achromatized or the eye had normal chromatic aberrat
ion. The target was moved sinusoidally toward and away from the eye at
a temporal frequency of 0.2 Hz over a 1 D amplitude (peak to peak). A
ccommodation was monitored continuously by an infrared recording optom
eter, and responses were Fourier analyzed to obtain gain and phase lag
at the temporal frequency of stimulation. Results, Accommodative gain
was highest and phase lag was smallest when the target was illuminate
d by white light in the presence of normal chromatic aberration. The a
chromatized white-light gain of accommodation was statistically simila
r to the gain for monochromatic targets, indicating that the presence
of chromatic aberration facilitates accommodation. Significant intersu
bject variability was present in the accommodative tracking ability to
monochromatic targets. Conclusions, Accommodation to monochromatic ta
rgets is not as accurate as accommodation to a white-light target, and
this effect is related to the presence of ocular longitudinal chromat
ic aberration for the white-light target.