The science of vision is a very intricate and complicated topic that demands much patience and comprehensive research for an in-depth understanding of the material. Because the makeup of the human eye is so complex, it would be nearly impossible for a person to truly understand all of the functionalities concerning the eye without thoroughly studying the topic at hand. Almost like an actual camera, the eyeball receives light through an opening (whereas the light receives the camera). It then has a specific lens to completely focus the sensitive membrane at the back of the eyeball.
A circular and radial muscle within the iris that unwinds and contracts to adjust the pupil’s size controls the light that gets to the eyeball itself. Firstly, the light must pass through the cornea, which in simple terms is a tissue put in place for the protection of the eyeball. Given its flexibility and adjustability, the cornea can reflect the light to center it towards the retina, located at the back of the eyeball. The retina, being covered in thousands, and millions of light-sensitive receptors, known as “rods” and “cones,” contain pigment molecules that change shape when hit by light.
These are just the basic functionalities of the eyeball, but more can be found and said about this topic through in-depth research. Information about the eyeball can be found on the Internet and within textbooks found on amazon or provided by professors. The high index of 1.74 can usually be found at the back of most ophthalmology textbooks. If satisfactory information is not found within a textbook, one can also look online or, better yet, watch documentaries about the eye and site for better understanding.