Accommodation through simulated multifocal optics

Abstract

We evaluated the interaction of multifocal patterns with eye's accommodation. Seven patterns were mapped on the spatial light modulator and the deformable mirror of an adaptive optics visual simulator, and projected onto the subjects' eyes, representing different contact lens designs: NoLens, Bifocal Center Distance (+2.50D), Bifocal Center Near (+2.50D) and Multifocal Center Near-MediumAdd (+1.75D) and Center Near HighAdd (+2.50D), positive and negative spherical aberration (±1µm). The change in spherical aberration and the accommodative response to accommodative demands were obtained from Hartmann-Shack measurements. Positive spherical aberration and Center Distance designs are consistent with a higher accommodative response (p=0.001 & p=0.003): steeper shift of SA towards negative values and lower accommodative lag.

Fig. 1.

Phase maps of the MCLs simulated in the SLM: MediumAdd (+1.75 D near add), HighAdd (+2.50 D near add), Center Distance (+2.50 D near add), Center Near (+2.50 D near add), right gray scale panels, and 1 µm positive and negative SA, left color panels, were induced on the DM. Maps are represented for a pupil diameter of 6 mm.

Fig. 2.

Left panel (A) Schematic of the AO system used in this experiment; Right upper panels (B): Illustration of the removal of SLM residuals on S4 with the HA pattern (1) Wave aberration measured in IR light (eye + SLM with MA pattern) (2) SLM residual of MA measured with artificial eye in IR light (3) Wave aberration of the eye alone after removing the SLM residual. Right lower panels (C): Illustration of adding the simulated CL computationally to the eye, shown as example of subject S4 with HA phase map. Pupil diameter was 4.36 mm for 0D and 3.24 mm for 6D.

Fig. 3.

Left panels: Pupil diameter changes with accommodation for all subjects plotted against accommodation demands from 0 to 6D. Right panel: Average slope (across subjects) for each condition. Red lines/bars represent NL; light brown represent CD; dark brown represent PSA; light green represent CN; bright green represent MA; olive green represent HA; darkest green represent NSA.

Fig. 4.

Left panels: Relative change in 4^th order spherical aberration of the eye alone for a fixed pupil diameter (shown in the lower left corner of each panel, representing the minimum diameter in the series, to which data have been cropped), for all conditions and subjects. Right panels: Average slope (across subjects) for each condition (spherical aberration/D). Red lines/bars represent NL; light brown represent CD; dark brown represent PSA; light green represent CN; bright green represent MA; olive green represent HA; darkest green represent NSA. Error bars stand for standard deviations across 5 repeated measurements.

Fig. 5.

Left panels: Spherical aberration of eye + phase maps for all subjects as a function of accommodative demands (D) for natural pupil diameters. The numbers in the left and right bottom of each panel indicate the pupil diameter (averaged across conditions, for 0 and 6D), for each condition and all subjects. Right panels: Average slope (across subjects) for each condition (spherical aberration/D). Red lines/bars represent NL; light brown represent CD; dark brown represent PSA; light green represent CN; bright green represent MA; olive green represent HA; darkest green represent NSA. Error bars stand for standard deviations across 5 repeated measurements.

Fig. 6.

Through-focus Volume under the MTF (3-5 c/deg) curves for subject S1 for each condition and all vergences (0-6 D, indicating by different line styles). The first row shows the NL condition, the second-row center distance conditions (PSA, CD), and the third row the center near conditions (CN, MA, HA, NSA).

Fig. 7.

(A) Accommodative lag (defocus shift in best image quality) for all subjects and conditions. (B) Average Slope of Accommodative lag curves (top: 0-3D accommodative demand; bottom: 3-6 D accommodative demand). Red lines/bars represent NL; light brown represent CD; dark brown represent PSA; light green represent CN; bright green represent MA; olive green represent HA; darkest green represent NSA. Error bars stand for standard deviations across 5 repeated measurements.