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L Chen, PB Kruger, DR Williams; Accommodation Without Higher Order Monochromatic Aberrations . Invest. Ophthalmol. Vis. Sci. 2002;43(13):956.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: It is well known that many subjects can accommodate to changes in target vergence in the absence of depth cues and even when the target is viewed in monochromatic light to eliminate a cue from chromatic aberration. In this situation, the eye’s higher order monochromatic aberrations could potentially provide an odd-error cue to focus direction (Wilson, Decker, and Roorda, ARVO 2000). We investigated whether monochromatic aberrations affect accommodation in experiments in which these aberrations were either present as they normally are or removed with adaptive optics. Method: Subjects viewed a maltese cross in monochromatic light (550 nm) through an adaptive optics system. On each trial, the deformable mirror in the adaptive optics system produced a step change in defocus, without a change of magnification, of either plus or minus 0.5 diopters, with the step direction randomly determined. The accommodative response was measured with a Shack-Hartmann wavefront sensor operating at 15 Hz. Responses were measured in two conditions, either with all the normal higher order monochromatic aberrations present or with these aberrations removed by the deformable mirror. Results: Of 5 subjects, two could not accommodate at all for steps in either condition, consistent with previous findings of large individual differences in the ability to accommodate in impoverished conditions. The remaining three subjects could accommodate in the correct direction even when higher order aberrations were removed. Conclusion: While these results do not exclude the possibility that some subjects can use monochromatic aberrations to guide accommodation, they show that subjects can accommodate correctly when higher order monochromatic aberrations as well as established cues to accommodation are removed.
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