Anatomy of the Eye
Despite vision being one of our most important senses, understanding the optical system and how our eyes work can be tricky. There are many different structures that work together to give us the clear sight we need for our daily activities.
To give you a basic idea of how our eyes work: light enters the front of the eye and travels through the center of the eye to the light-sensitive tissue at the back of the eye. There, it is converted into electric signals. The signals are then sent to the part of the brain that controls our sense of sight.
The cornea is the transparent dome-like layer covering the front of the eye. A healthy cornea is round and shaped like a basketball. Light passes through the cornea and is focused on the retina at the back of the eye.
The iris is the colored part of the eye. At the center of the iris is the pupil, a circular opening that widens and shrinks depending on how much light is entering the eye. If there is a lot of light, the pupil shrinks; if there is too little light, it dilates (i.e., widens).
The lens is a structure that sits behind the cornea and the iris. Its job is to work with the cornea to focus light rays entering the eye onto the retina. A healthy lens is clear. The lens is supported by the ciliary muscles, which help it change shape to change the focal distance of the eye. The muscles contract and relax to help the lens focus on nearby and faraway objects.
The vitreous body is a chamber located behind the lens. It is filled with a clear, jelly-like substance that helps the eye keep its globe-like shape.
The retina is a layer of tissue that lines the back wall of the eye. Its photoreceptor cells receive the light that the lens has focused, process it and convert it into electric signals to send to the brain. If the retina starts to pull away from its normal position in the back wall of the eye, it can no longer receive or process light and the brain cannot receive this information.
The macula — the central portion of the retina — has a high concentration of photoreceptor cells. It is the part of the retina responsible for providing clear detailed central vision.
The macula is made of many tightly packed cones and is covered and protected by a layer of tissue called the macular pigment. The macula is the area of tissue most damaged by macular degeneration. New medical foods, like Lumega-Z, provide nutritional support for macula health by restoring and replenishing the macular pigment layer.
The optic nerve is a bundle of approximately 1 million nerve fibers that send the electric signals from the retina to the visual cortex of the brain. Made up of ganglionic or nerve cells, the optic nerve is sensitive to changes in pressure inside the eye (a measure known as intraocular pressure). When fluid can’t properly drain out of the eye, intraocular pressure can spike or gradually rise, and the pressure can compress the optic nerve, causing irreversible vision loss.
For more information about the anatomy of the eye and the problems that lead to serious diseases including glaucoma and age-related macular degeneration, please contact Guardion Health Sciences today.