The Sunburst Diving Beetle has great eyesight, in part due to a bifocal lens. The larvae of the beetle go through multiple molting periods in their trek to adulthood — which means it reshapes its own eyes.
In the picture below we see two different stages of the Sunburst Diving Beetle. There’s quite a difference between them. The beetle goes through three different molts before it reaches maturity, each time radically changing its physique. This is especially remarkable because the beetle has such impressive eyes. The eyes of the beetle have built-in bifocals, allowing it to accurately see objects very far away from it and very close to it.
Researchers looked into how a beetle goes about re-shaping its own eyes during the moult period. They monitored beetles during the moult between their second and third stage of development. Periodically, they took closer looks at the beetles’ developing eyes. What they found was equal parts frustrating and remarkable. They first checked an hour into the moult, and found the structures for the beetles’ eyes already in place. The beetle had regrown its eyes in the time it takes for most people to watch one episode of 24.
This makes sense, when you think about the fact that the beetle is blind while its eyes are reforming. Every minute gone is another minute a predator could swoop by. And it takes the beetles up to eight hours to adjust their lenses well enough to see clearly.
Still, one hour to new eyes is pretty impressive.
[Source: Rapid and step-wise eye growth in molting diving beetle larvae.]