A sample of double-pass images recorded with unequal entrance (1.5-mm) and exit (4-nim) pupil diameters in the apparatus in six young subjects of group A is shown in Figure 3These images depict the intersubject variability in the retinal image. Although the average spread of every image is approximately similar within the same age range, there are substantial differences in the shape of the images, indicating the variability of the aberrations among subjects.