When swimming underwater, everything around you appears blurred. That's because water represents a very different environment for our eyes, which have been created to be able see in an atmospheric environment. Accordingly, a fish taken out of its normal habitat into an atmospheric environment might also be expected to see everything as blurred. However, one species of fish, which lives in rivers and lakes from Southern Mexico to northern South America, can see very well both in the water and above. This is the anableps, better known as the four-eyed fish. Not only able to see very clearly outside the water, this fish can even focus on objects in the air.
The anableps actually has only two eyes, but each is divided horizontally; that is, each eye has two separate optical systems, each with its own focal length. This flawless design explains why the anableps see two different images at the same time. When swimming slightly beneath the surface its pupils remain above the surface of the water and constantly scan the air. In this way the fish is able to feed on flying creatures or flee swimming ones.
The two separate focal points in the fish's eye let it receive two images at the same time.
A spotted band of tissue containing pigment and each of the visible irises divide each eye into two halves at the water line, and these form two pupils, one above the water and the other beneath it. Looked at from above, the irises resemble fingers floating in the air inside protuberant eyes.
The four-eyed fish is able to leap into the air to catch insects and to dive into the water to hunt swimming creatures. However, it mainly catches crustaceans moving in the shallow water near the shore, algae, or insects trapped on the water's surface.
Scientists have established that the fish pays more attention to the air, where it can perceive objects that are smaller and more distant. Even so, it frequently dives down into the water to feed or to escape predators.
How Did This System Come Into Being?
It's no doubt that it is impossible for a fish to design two different visual optical systems for itself, according to the different optical properties of air and water, and then to install both systems so that they can work in harmony within a single eye.
Could its eyes have come into being by random processes, as the theory of evolution maintains? In other words, could this optical design—the likes of which is found nowhere else—have appeared by chance mutation in one individual's eyes, and then have been transmitted to subsequent generations?
Of course not. Complex structures such as eyes depend on a great many inter-related components working together. The absence of or a defect in any one will mean the eye serves no purpose at all. Systems like this are known as "irreducibly complex." For example, the human eye cannot be reduced to any simpler form, since without every single one of its features, it can serve no function at all. This is further proof that the eye couldn't have "evolved" in stages over the course of time.
As Darwin himself admitted, "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." (Charles Darwin, The Origin of Species: A Fascimile of the First Edition, Harvard University Press, 1964, p.189) This single example undermines the very foundations of his theory of evolution.
Darwin was aware that he faced a grave dilemma with regard to the "evolution of the eye." Indeed, he confessed this in the chapter of his book called Difficulties on Theory. The American physicist H. S. Lipson, who read Darwin's book, made the following comment about these "difficulties" of Darwin's:
On reading The Origin of Species, I found that Darwin was much less sure himself than he is often represented to be; the chapter entitled "Difficulties of the Theory" for example, shows considerable self-doubt. As a physicist, I was particularly intrigued by his comments on how the eye would have arisen. (H. S. Lipson, "A Physicist's View of Darwin's Theory", Evolution Trends in Plants, vol. 2, no. 1, 1988, p. 6.)
Since evolutionists can't account for the emergence of a single eye, they obviously can offer no explanation of the origin of the four-eyed fish, which can see as well as a human being above the water, but as well as a fish underneath it. The four-eyed fish, has been created by God, with an extraordinary system, using no previous models, and utterly flawlessly.
Evolutionists refuse to see this obvious truth and still insist on believing in nonsense, but everyone else should determinedly avoid falling into the same error.
This deep lack of understanding is given to them in return for their rejection of the existence of God. In one verse God reveals:
Do not be like those who forgot God so He made them forget themselves. Such people are the deviators. (Surat al-Hashr: 19)
Since the refraction indices of water and the eye's cornea are nearly the same, light reflected from underwater objects passes directly through the cornea and is focused in the lens, which has a higher index. Air, on the other hand, has a lower refractive index than the cornea, for which reason the light is refracted twice. The anableps sees both images clearly by using its flawless, egg-like lenses. The section of the lens at the same level as the pupil has been given a spherical shape, just like a fish's eye. A swimming insect larva can thus be focused onto the retina. The less rounded upper part, on the other hand, more closely resembles the human eye and compensates for the two refractions that take place when looking at objects in the air. The fish can thus see even a mosquito perfectly clearly. This perfect design is just one of the countless examples of God's incomparable creative artistry.