For many sea-dwelling animals, seeing is extremely important for
hunting and defence. Accordingly, most of the sea-dwelling animals are equipped with eyes
perfectly designed for underwater.
Under water, the ability to see becomes more and more
limited with depth, especially after 30 meters. Organisms living at this depth, however,
have eyes created according to the given conditions.
Sea-dwelling animals, unlike land-dwelling animals, have spherical
lenses in perfect accordance with the needs of the density of the water they inhabit.
Compared to the wide elliptical eyes of land-dwelling animals, this spherical structure is
more serviceable for sight under water; it is adjusted to see objects in close-up. When an
object at a greater distance is focused upon, the whole lens system is pulled backwards by
the help of a special muscle mechanism within the eye.
One other reason why the eyes of the fish are spherical is the
refraction of light in water. Because the eye is filled with a liquid having almost the
same density as water, no refraction occurs while an image formed outside is reflected on
the eye. Consequently, the eye lens fully focuses the image of the outside object on the
retina. The fish, unlike human beings, sees very sharply in water.
Some animals like octopus have rather big eyes to compensate for the
poor light in the depths of water. Below 300 meters, big-eyed fish need to capture the
flashes of the surrounding organisms to notice them. They especially have to be sensitive
to the feeble blue light penetrating into the water. For this reason, there are plenty of
sensitive blue cells in the retina of their eyes.
As is understood from these examples, every living being has
distinctive eyes specially designed to meet its particular needs. This fact proves that
they are all created just the way they have to be by a Creator Who has eternal wisdom,
knowledge and power.