On the gekko pupil and Scheiner's disc.
The four pinhole apertures of the constricted gekko pupil are an adaptation for decreasing the depth of field of the eye, while decreasing the total light flux to the retina. This may be useful for distance estimation at high light levels.
D000818:Animals; D008116:Lizards / Q000502:physiology*; D011680:Pupil / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*