While there are not many things that an octopus and human being have in common, octopuses may actually be the key to detecting early signs of human age-related macular degeneration. A study, led by Professor Shelby Temple at University of Bristol, looked into polarization vision systems in animals, and how this technology can improve testing in humans for age-related macular degeneration (AMD). It was recently published in the Journal of Experimental Biology.
Since light travels in waves, polarized light refers to light that vibrates on the same plane (the same “surface” or level). Essentially, the more the light waves deviate from the plane, the less “polarized” the light is. Several marine animals (including octopuses) are colourblind, and this is due to how wavelength significantly affects light transmission in bodies of water. Because of this, being able to see with colour does not bring much of an advantage to marine species. Instead, they will use their coloured vision in order to take advantage of the certain wavelengths that may be present in their surroundings.
Cephalopoda, the class category for octopus, cuttlefish, and squid, use photoreceptors to detect light. Overtime, these photoreceptors have evolved into perceiving the orientation of polarized light. This drastically contrasts from the way humans perceive light, such that macular pigments in the eye absorb higher frequency light (blue or violet light). This forms a shadow on the retina, which as a result helps absorb polarized light. The more macular pigments a person’s eye contains, the better protected they are against sight loss. The reason for this is because these pigments are the body’s natural protection against violet-blue light, which tend to have higher frequencies, shorter wavelengths, and therefore more energy.