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The effect of longitudinal chromatic aberration on the lag of accommodation and depth of field

2016; Wiley; Volume: 36; Issue: 6 Linguagem: Inglês

10.1111/opo.12320

1475-1313

Matt Jaskulski, Iván Marín‐Franch, Paula Bernal‐Molina, Norberto López‐Gil,

Optical measurement and interference techniques

Abstract Purpose Longitudinal chromatic aberration is present in all states of accommodation and may play a role in the accommodation response and the emmetropisation process. We study the change of the depth of field ( DOF i) with the state of accommodation, taking into account the longitudinal chromatic aberration. Methods Subjective DOF i was defined as the range of defocus beyond which the blur of the target (one line of optotypes of 0.1 log MAR shown on a black‐and‐white microdisplay, seen through different colour filters) was perceived as objectionable. The subject's eye was paralysed and different, previously‐measured accommodative states (corresponding to the accommodative demands of 0D, 2D and 4D) were simulated with a deformable mirror. Different colour conditions (monochromatic red, green and blue and polychromatic (white) were tested. The DOF i was measured subjectively, using a motorised Badal system. Results Taking as reference the average accommodative response for the white stimulus, the blue response exhibits on average a lead of 0.45 ± 0.09D, the green a negligible lead of 0.07 ± 0.02D and red a lag of 0.49 ± 0.10D. The monochromatic DOF i, calculated by averaging DOF i over the red, green and blue colour conditions for each accommodative demand was 1.10 ± 0.10D for 0D, 1.20 ± 0.08D for 2D, and 1.26 ± 0.40D for 4D. The polychromatic white DOF i were greater than the average monochromatic DOF i by 19%, 9% and 14% for 0D, 2D, and 4D of accommodative demand, respectively. Conclusion The longitudinal chromatic aberration causes a dioptric shift of the monochromatic accommodation response. The study did not reveal this shift to depend on the accommodative demand or to have an effect on the DOF i.