Figure 3.

Subjects watched movies on the screen at 2000 mm distance. As proposed by Marcos et al.²², subjects are assumed to be in best focus at 570 nm (see illustration at the bottom of the Figure). According to the LCA function in human subjects (shown below in Fig. 4), the red channel in RGB (630 nm) is defocused hyperopically by − 0.23D, the blue channel (450 nm) myopically defocused by + 1.10D while the RGB green channel (538 nm) is slightly myopically defocused by + 0.24D. The respective calculated blur circles are shown in red box 1. Movies were filtered as shown in red box 2. With the filter “red in focus”, the image of the red channel remained untouched while green and blue were spatially filtered according to the LCA. With the filter “blue in focus”, the image of the blue channel remained untouched while red and green were spatially filtered according to the LCA. Combining box 1 and 2, the blur circles on the retina could be changed so that either blue was low pass filtered and red was sharp, or both were low pass filtered by combining natural LCA with the calculated blur circles accordingly to the LCA function (box 3).