Updated: Nov 2, 2022
The human eye is a complex organ and can be thought of as one of the most advanced and capable vision systems in existence.
What camera system has all of these attributes?!!
Pan- and tilt
Stereo vision and depth sensing
Curved image plane
Ultra-high resolution & foveated vision
High dynamic range (HDR)
Peripheral motion detection
On-chip signal compression
Pattern matching, object recognition or "advanced AI"
Humans have been curious about how the eye works for thousands of years. Early debates about how the eye worked centered around theories of "extramission" where it was thought to emit light and scanned what was reflected back, or "intromission", where the eye was thought to only receive light. These theories were debated into the Renaissance period by scholars like Leonardo Davinci. In 1604, Kepler was the first to suggest the correct function involving a lens and image formation at the retinal plane. Since then, research to uncover and fully explain the human visual system has become a broad and fruitful area of scientific and cognitive discovery.
Today, the optical principles of image formation and light sensing by the retina are well understood, yet how all the different types of retinal neurons and cortical neurons function to produce the visual experience is still an active area of research and investigation.
The basic principles of the human vision system align with the core functions of a camera, composed of a lens and image-sensing element. The human eye lens and retinal plane are exquisitely optimized to work as an efficient image-capturing system.
The image above shows how the eye's cornea, lens, and iris work like a camera lens to focus light to an image plane - the retina. As with typical lenses, the image is inverted. At the retina, rod and cone photoreceptors sense the focused light and emit an electrical response that travels through a series of retinal neurons, through the optic nerve, and ultimately to the visual cortex.
The eye is a fascinating optical system and is often described as the "window" into the body. Optical devices for imaging and measuring the eye help improve vision, and detect and prevent diseases not only in the eye but across the entire body as well.