Oliver Sacks, “The Island of the Colorblind“, 1997 was the topic of an earlier blog post. The Micronesian isle of Pinggelap suffers from hereditary achromatopsia (colorblindness) and neurologist Oliver Sacks describes this eye condition. While “cone cell” blindness is present, the “rod cell” is functional. In the diagram above, I show the visual process in the eye rod cell. The eye rod cell is one of “16 transducer cell-types” out of the 211 human cell-types. On the Roche Biochemical webpage , the diagram is location “V”, and coordinate “4”. Retinal isomerase, Enzyme Commission 22.214.171.124 can be seen in the center of the diagram.