ETNOCENTRICITY

  We use to think that ophthalmology deals with human vision, the vision system of the most advanced species. At most, we grudglingly concede that also the insect eye is pretty advanced and that we do not quite understand how the insect brain, whatever there is, can compilate the multipicture it receives.

 DARWIN famously wrote in On the Origin of Species that the eye is so complex that its evolution by natural selection seems "absurd". And André Breton, Senior Surrealist, said that “the eye exists in its savage state”. These statements make good sense when one regards the eyes of Tripedalia cystophora of the gnidarian family. These provide the freswimming and evilly stinging cubozoan jellyfish with 360 degree vision from its “bizarre cluster of eyes”,  4x6 = 24 of them,  placed om ropalliums around the guy´s periphery, and feeding four parallel brains.

 In a recent article in Nature, Nilsson et al also show that “box-jellyfish lenses contain a finely tuned refractive gradient producing nearly abberation-free imaging”. This certainly shows that “even simple (indeed..) animals have been able te evolve the sophisticated visual optics previously known only from..” etc etc. Unfortunately the retinae of these eyes are not correctly placed to receive the sharpest image. Sloppy construction, one might say...certainly no “intelligent design” or creationism, nor common sense Darwinism. Nilsson suggests that“cubozoan eyes are good for spotting large, stationary objects, while filtering out unnecessary detail such as plankton drifting with the current.” If so, why would the rest of a good imaging system (cornea, iris, lens, retina) have to be there? Seems like quite some overkill.

  It is tempting to instead listen to Fred Hoyle and Chandra Wickramasinghe who have some interesting suggestions for a more complicated evolutionary process. Brace for the impact...you will have the intellectual roller coaster ride of the day.

   Be all this as it may...some vision things are certainly happening outside the interest sphere of our most revered and peer reviewed ophthalmology journals or pub.med.search engines. And it pays to look outside once in a while. Let google search for vision....surprising things come up. Not necessarily useful for your choice of cataract sutures or glaucoma medication.

   But food for thought.

  The article about jellyfish vision was found in Nature, go read here or here for more information. If your library has a proper license you may even be able to read the full Nature article o