The Eyes

The Eyes: Function & Anatomy

The eyes are key sensory organs that feed the brain information about the outside world. They do the physical part of seeing, and their signals allow the brain to build a picture of what we see. Eyes are complex and take many parts working together to function. The eye is a slightly asymmetrical globe about an inch in diameter. It sits in a protective bony socket in the skull called the orbit. Six extraocular muscles in the orbit attach the eye to the skull.

Parts of The Eye:  

The eye is made up of many layers of tissues, fluids, and other structures. 

• External Structures: this includes eyelashes, lids, muscles, accessory glands, and conjunctiva. 
• The conjunctiva is the thin membrane covering the eye
• The sclera is the whites of the eye, and is a tough, fibroid layer of collagen fibers that surrounds the eyeball and attaches to the cornea
• The cornea is the transparent front surface, which is a fixed-focus lens
• Middle Layer: this is vascular and includes the uvea, which is made up of the iris, ciliary body, and choroid. The choroid contains blood vessels that supply oxygen and nutrients to the inside of the eye. 
• The iris is the colored part of the eye, which is a muscular ring
• The pupil is the hole inside the ring of the iris
• The ciliary body is the structure of the eye that secretes transparent liquid within the front of the eye 
• The choroid is the layer of blood vessels between the sclera and retina

• Innermost Layer: this is made up of nervous tissue called the retina. 

The retina is the curved back layer of the eye, which is covered in light-sensitive cells called rods and cones. They can see shape, color, and pattern

• The macula is a small, oval-shaped, pigmented area in the center of the retina at the back of the eye that is responsible for central vision, color vision, and fine details
• The fovea is the depression in the very center of the macula, where eyesight is the sharpest
• Fluids: the eye is filled with fluids that are called humours.
• The aqueous humour is the fluid that fills a small chamber just behind the cornea 
• The vitreous humour is a thick, jelly-like fluid that fills the eyeball and keeps it firm
• Tears lubricate the eye and make up three layers called the tear film
• The lens is a fine-focus lens made of a highly concentrated protein solution that gives it refractive power
• The optic nerve sends information or signals from the retina to the brain to be interpreted
• Eye color is determined by multiple genes inherited from each parent and is created by the amount and type of pigment in the iris. 

Vision 

We have binocular vision, and the right and left eyes each have slightly different views. The brain then combines the two views, resulting in a three-dimensional image. The cornea has a fixed focus, and adjustments in focus are made by the lens that sits just behind the iris. The cornea has tiny muscles that can change shape to adjust for how far or near the focus needs to be. 

The colored part of the eye, or the iris, is a muscular ring that controls the amount of light that enters the eyes. It causes the pupil to dilate in darkness or constrict in bright light. 

No rods or cones are at the back of the retina where the optic nerve enters. This is a tiny patch of blindness or a blind spot. The brain compensates for this blind spot by processing the surrounding image and filling in the blank spots accordingly. 

The macula is about 5.5 millimeters in diameter and is the most sensitive part of the retina. We use this when we are looking directly at objects, such as when we are reading. At the center of the macula is the fovea, which contains high concentrations of cone photoreceptors, or light-sensing cells 

Systems & Hormones: 

Vision is a process that involves many body systems working together. These include the eyes, brain, and the nervous system. The retina is a neural portion of the central nervous system (CNS). When light hits the retina, light receptors trigger chemical reactions, sending electrical signals through the optic nerve. The neural system of the visual system includes the optical nerve, optic chiasm, optic tracts, lateral geniculate nucleus (LGN), and the visual cortex. These parts of the nervous system process visual stimuli from the retina into nerve impulses that travel to the brain. The parasympathetic system helps the eye focus on closer objects by constricting fibers. 

Many hormones are involved in this body system. Estrogen and progesterone affect eye oil glands, affecting moisture, elasticity, and how light travels to the eye. Thyroid hormones affect the muscles around the eye and can impact the optic nerve and vision. Testosterone helps to maintain the meibomian glands that produce the oily layer of tears. Melatonin has recently been correlated with neuroprotection of the eye. Insulin can also affect vision. 

Eyes are also affected by the sleep-wake cycle and vice versa. During the deepest sleep phase, blood flow to the eyes increases, which helps deliver essential nutrients and flush out toxins. This process aids in the restoration and repair of cells in the eyes. Blue light, whether from the sun or screens, communicates via our eyes with our brains when daytime is and when we should be awake. Exposing our eyes to blue light at the wrong time can disrupt our sleep cycles, which in turn can affect our vision if we are sleep-deprived.

 

Fun Body System Facts: 

• The eyes have more than 100 million light-sensitive cells. 
• The eyes function like cameras capturing light and sending data back to the brain. Eyes see things upside down, and our brains turn the image the right way up.
• We can blink as many as five times in one second.
• The eye is the fastest muscle in the body.  
• If the eye were a camera, it would have 576 megapixels.
• Brown is the most common eye color. Green eyes are one of the rarest eye colors. Some conditions can make it so that eyes are gray, red, or violet. 

What is necessary for optimal eye health? 

Our eyes crave a well-balanced, nutrient-dense diet. Fruits and vegetables, especially leafy greens such as spinach and kale, omega-3 fatty acids such as fish like salmon, tuna, and halibut, and Vitamins C and A are especially important for eye health. Being active helps with blood flow to the eyes. Being sure to rest your eyes and do eye exercises helps to keep your eyes in optimal health. 

Nutrition Support: 

Leafy Greens	Salmon	Carrots	Peaches/ Apricots	Gamma-linolenic Acid
Nuts & Seeds	Sweet Potatoes	Red Peppers	Vitamins: A, C, E	Carotenoids
Fruits	Beans & Legumes	Sunflower Seeds	Zinc
Vegetables	Blueberries	Spinach	Lutein
Omega-3’s	Dark Chocolate	Raspberries	Zeaxanthin

Eye Health Recipe: Bright Eyes Smoothie

Eye nutrition can be as easy as a delicious smoothie! This smoothie is full of fiber, potassium, antioxidants, vitamins, carotenoids, beta-carotene, omega-3s, lutein, and zeaxanthin, making it a powerhouse for eye health! 

 

 

 

Ingredients

• 3 fresh apricots, pitted
• 2 fresh peaches, pitted
• 1 cup fresh squeezed orange juice
• 1 tablespoon ground flaxseed
• 1 tablespoon raw sunflower seeds
• Ice
• Optional: honey to taste, Celtic sea salt for added minerals

Directions

Place all of the ingredients in a blender. Blend on high speed until completely smooth.

Lifestyle Support: 

• Wear blue-light glasses when looking at screens
• Use safety eyewear when appropriate 
• Give your eyes a break when looking at something for long periods of time
• See to blood sugar and blood pressure health
• Practice eye exercises
• Find ways to de-stress and relax
• Eat a nutrient-dense diet
• Get plenty of sleep 

Herbal Friends of the Eyes: 

Rehmannia	Chinese Yam	Asiatic Dogwood	Tree Peony	Alisma
Poria	Cinnamon	Marigold	Bilberry	Eyebright
Gingko	Fennel	Green Tea	Turmeric	Grapeseed
Goldenseal	Passionflower	Saffron	Yarrow	Calendula

Companion RidgeCrest Products: 

• EssentialEyes®
• Blood Pressure Formula™
• Blood Sugar Balance™ 
• SereniZen® formerly Anxiety Free

Supporting Supplements: 

• Gamm-linolenic Acid- Primrose Oil 
• Zeaxanthin & Lutein
• Grapeseed Extract
• Resveratrol

Related Blogs:

• Physiology: Eyes
• The Third Eye
• The Pineal Gland
• Blue Light and Circadian Rhythms 
• Eye Exercises 

 

About The Author:

Shae Brackett is our Customer Service Director and Social Media Manager and has been with RidgeCrest since 2016. Shae is the mastermind behind our exceptional customer experience, ensuring every call, email, and customer experience is handled with love and care. She guides the customer care team, is our culture caretaker, helping to facilitate our employee experience, and our online creative oracle for our Facebook, Instagram, blog, and meditations. She describes herself as creative, thoughtful, nature-loving, compassionate, and nurturing. Her favorite herbs are Ginger and Lavender, and she proudly recommends SereniZen® (formerly Anxiety Free), PhysiQOL™, SinusClear®, and Belly Be Happy®.  Learn more about our team here.