just about everything, including humans, see by refracting (bending) light through a lens (right behind your pupil) to focus it onto the retina where rods and cones detect the image and send the info to your brain. this works great except when your trying to see in very muddy water. lobsters do not refract, they reflect. refracting takes the light that is immediately available directly infront of the pupil and it works great when light is abundant and the viewer can afford to ignore the stray light photons that do not fit the standard light-path. the major of light in the lobster habitat are are those stray photons and there is not enough of them for good visibility. the average light-path is obscured by the murky water. what the lobster does is to take the stray light photons and reflect them to their retina. take ten projectors on one wall and point them in ten different directions. put some obstacles in the center of the room so the image does not reach the opposite wall. now place mirrors along the sides and focus each image onto a single area on the opposite wall bypassing the obstacles in the center so you have a single image on opposite wall. those mirrors are a model for how the lobster sees in its impossible to see habitat.

so how is this useful for us? the eye of the lobster is being used as a model for new deepspace telescopes and security screening devices. the telescopes work by focusing the scattered light/x-rays/gamma rays/whatever from deep space into an identifiable image that would otherwise be unintelligible. what is really interesting is the security screening devices.

these hand held devices emit low frequency x-rays in order to see through walls/boxes/etc. traditional x-rays expose an object and record the image on the film behind what is being exposed. the image is formed by the x-ray photons that were not able to reach the film. this device does the opposite. it emits the radiation and detects the scatter radiation that is coming back through the wall/object/container and focuses it using the lobster eye model to create the image. it is not a good enough image for medical use, but the image is good enough to screen containers being shipped into the country or scan a wall/door to see where the criminal/attacker is hiding. the potential for this technology is huge and, frankly, just down right cool.

university of melbourne, school of physics on lobster eyes
howstuffworks on lobster eye lenses
thought criminal on lobster eye lense for screening
lobster eye lens on usa today
lobster eye lens with compton scatter