OPHTHALMOLOGY

Gregory Eippert, MD

Q: Basically, how do our eyes work? What is unique about human vision? A: In basic terms, human vision has four components. 1) Light comes into our eyes passing through the cornea, pupil, and lens. 2) The light continues through the eye to the back layer of the eye, the retina. 3) The rods and cones of the retina generate impulses that are sent thru the optic nerve to the visual cortex part of the brain. 4) The brain interprets the impulses into the images we see. Human vision is actually a visual system and much more dynamic and intricate than these four basic components. The human eye is the second most complex organ in the body after the brain and encompasses an extraordinary range of abilities that we use to navigate through our world. We see color, detect motion, identify shapes, gauge distance and speed, and can alternately focus on objects at a variety of distances. We see in three dimensions. We can also fill in blind spots and automatically correct distorted information that we may visualize. Our eyes are highly moveable and allow for a wide visual field, up to 200 degrees horizontally (side to side) and 130 degrees vertically (up and down). The part of the eye that accomplishes these tasks is the retina which contains around 150 million lightsensitive rod and cone cells. The retina is actually an outgrowth of the brain and is connected to the brain by the optic nerve. The optic nerve conveys the signals from the retina to the visual cortex in the brain where hundreds of millions of neurons process the signals and produce our vision. This process requires the use of 65% of our brain power, more than is used by any other organ in our body. Our eyes are one of our most useful senses and enable us to participate in daily life activities and enjoy the world in which we live. Even if your eyes are normal and you have good vision, they can change over time like any other part of the body. This is why it’s important to find an eye doctor and have regular, comprehensive eye exams. Many eye and vision problems have no obvious signs or symptoms. Early diagnosis and treatment of eye and vision problems is important for maintaining good vision and eye health.