The evolution of the human eye
People’s eyes tell more than their mouths. Let’s learn the evolution of the human eye!
The human eye is an amazing mechanism able to detect anything, and anywhere. Charles Darwin acknowledged that once an eye was created by random chance then selective pressure would give rise to the diversity seen within different species.
500 million years ago, a story of the human eye initiates with a simple light spot found in single-celled organisms like euglena which is a cluster of light-sensitive proteins linked to the organism’s flagellum activates when it finds the light. Being cupped enables it to sense the light better. Over the millennia as the light cups grew deeper the opening at the front grew smaller which resulted in a pinhole effect diminishing the distortion by allowing a thin beam of light into the eye, eg nautilus.
Cornea, a transparent cell covering the opening to prevent the eye, allowing the inside of the eye to fill with fluid that optimizes light sensitivity and processing, crystalline proteins formed at the surface created a structured lens in focusing light at a single point on the retina, Tear glands that secrete a protective firm. This structure of a pinhole camera with a lens and a colored ring called iris with sclera to maintain the structure serves as the basis to evolve into the human eye. The expansion of the visual cortex to process the images it’s receiving.
Our eye bares traces of its evolution i.e. inverted retina with light-detecting cells facing away from the eye-opening which results in the blind spot, where the optic nerve must pierce the retina to reach the photosensitive layer.
An example of a doozy is Anableps, a four-eyed fish that has 2 sections of the eye for looking above and underwater, Cats with night vision glow, etc.
Doctors are creating biomechanical implants for the visually impaired based on the different eye structures.
The human eye might even enable to surpass its own evolution.