ANSI/IES LS-7-20—Eye and Brain Visual System
A study from MIT found that the brain can identify entire images that are seen for as little as 13 milliseconds. The optic nerve, the line from the eyeball to the brain, connects the eyes to the brain—enabling the brain to create a sense of vision from the external image that the eyes captured from the visible light. ANSI/IES LS-7-20— Lighting Science: Vision – Eye And Brain applies to the human visual system.
Vision and Perceptions
The interaction of the eyes and brain results in vision. From vision comes perceptions, and hence visual perception is the ability to see and interpret one’s visual environment. From perceptions we are able to build our unique, individual worlds. Our view of the world is tremendously affected by the luminous environment. ANSI/IES LS-7-20 considers the eye and brain as a single unit to help us grasp the biological machinery that provides vision.
What Is ANSI/IES LS-7?
ANSI/IES LS-7-20 explains the human visual system, including its components in the eye and the brain. The American National Standard describes the structure and function of these various components as well as the ways in which individual people differ in their visual abilities—including the effects of age on vision.
The standard covers components of the eye such as the retina, optic nerve, and visual cortex and how the eye adapts has to the prevailing light condition in order to function well. ANSI/IES LS-7-20 also discusses visual perceptions: the result of the visual system’s processing of optical input. These perceptions include brightness, lightness, color, depth, and motion.
Optical Illusion Science
Our experience of reality, however, is not perfect. We often have misperceptions of reality, meaning the story our brains generate do not always matches the real world. This is why optical illusions exist; our brains unconsciously bend our perception of reality to fill in gaps using our past experiences. As humans, we do not have (and would not want) the necessary machinery to carefully process all of the information that continuously bombards us. The way we are wired enables the brain to predict the path of motion before it happens—before it becomes our reality. This is what allows us to hit baseballs with bats, swat away flies, or catch a football. Since our sensory systems are lagged, meaning they are not informing us what is presently occurring but what is occurring hundreds of milliseconds ago, we have evolved to predict the future so we are more coordinated and get hurt less often.
Eye and Brain Connection
Our brain does not have sensory abilities of its own. It needs our eyes (and other senses, like hearing and touch) to gather information about the world around us. The eyes and brain work together to process the outside world. The eyes are the “physical” part of seeing, telling us the color, texture, size, and shape of an object as well as its depth, distance, and size. Whereas, the brain “builds” the picture, processing and analyzing the visual information we physically see. For example, the brain gives you the information to recognize your friend in a crowded room.
How does this eye and brain connection exactly work? Well, the eye and brain are connected through the optic nerve. When light hits the retina (i.e., a light-sensitive layer of tissue at the back of the eye), rods and cones (i.e., photoreceptors/specialized cells) can convert light energy into nerve signals. These signals travel through the optic nerve to the brain, where the visual cortex interprets them as images, creating our perception of what we see.
ANSI/IES LS-7-20— Lighting Science: Vision – Eye And Brain is available on the ANSI webstore.
