Education, study and knowledge

The 11 parts of the human eye (and their characteristics)

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They say that the eyes are the windows to the soul, that just by looking at a person we can know them completely. By staring we become aware of the lies, truths, and reactions we cause in others.

See every detail of the world and discover the beauty in the colors and shapes that everyday life has. But have you ever wondered: How exactly does our ocular system work?

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After all, it is made up of many parts that we can see and others that we cannot because they are within our brains, connected by thousands of nerve endings that work to make our eyes. Are you curious to find out more?

In this article we will talk about the parts of the eye and all its characteristics so you can appreciate all the inner work that makes seeing possible.

How does the human eye work?

Essentially, the human eye is a photoreceptor organ, that is, it is capable of detecting light and its nuances, to give shape and meaning to objects in the world. This occurs thanks to the transformation of light energy into electrical impulses, which are sent through the optic nerves to the vision nerve center, located in the occipital part of the brain.

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There are 6 eye muscles that are responsible for performing eye movements (up, down and sideways) and to focus convergently. That is, both visual fields (left and right) can be oriented towards the same object that is being viewed. This is thanks to a simultaneous operation of both.

Human eye anatomy

The human eye is a sphere with a radius of 12 millimeters, with a kind of dome on its front, which has a radius of 8 millimeters. It is also extremely sensitive to external agents that penetrate inside, including the smallest such as dust or water droplets, because it is an innervated organ, which means that it has many fibers nervous.

But also, has an anatomy that can be divided into three major structures, depending on their layers. Which have different parts that are responsible for a specific function. Find out what they are.

Eye anatomy

1. Outer layer of the eye

It is the "invisible" layer that supports and protects the entire eye organ., as it is in the front part, exposing itself to external factors and agents of the environment.

1.1. Cornea

This refers specifically to the convex dome or spherical cap that covers the eye as such. It is characterized by being a transparent tissue without blood vessels, although it is affected by the innervation of the eye that connects it to the nervous system. Its main function is to refract and send light towards the back of the eye, that is, towards the retina.

1.2. Sclera

This part is visible to us, we know it as the white background of our eyes, where it is also observable small blood vessels in addition to the iris. It is also known as the ocular skeleton, as it is what helps it to retain its shape.

Its structure is opaque and fibrous in texture and it contains the external muscles that allow the movements of the eye.

1.3. Conjunctiva

It is a membrane that surrounds the sclera and its function is the production of tears and mucus. Which serve as a form of lubrication and natural disinfection of the eye.

2. Middle layer of the eye

It is the visible layer, since it represents the focal point of the entire eye organ, including its color.

2.1. Choroid

They contain the blood vessels and connective tissue of the eyeball, which oxygenate and nourish it so that it can function properly. They also have a kind of pigment that helps reduce excess brightness, thus preventing blurred vision.

2.2. Crystalline

It is the natural lens that the eye has and its main function is to focus on objects perceived from different distances, helping the retina to shape the image we are seeing.

It is located behind the iris and is composed of a biconvex, elastic and transparent lens, which has the ability to change shape to adapt its focus. This ability is also known as "accommodation."

2.3. Iris

We know this structure as the one that has the color of our eyes (which is given according to our concentration of melanin). But it is also responsible for protecting and regulating the amount of light that enters our eyes and according to the level of illumination. present around us has the ability to contract or dilate, processes called miosis and mydriasis respectively. It also serves as a separation of the anterior and posterior layer of the eye.

2.4. Pupils

We can see it as the small black hole in the center of the iris, since it is bordered by it. It is a hollow cavity, so it is possible to see the inside of the eye itself. This works together with the pupil in regulating the amount of incoming light, so it also has the capacities of mydriasis and miosis depending on the ambient light.

2.5. Ciliary body

It is responsible for several functions that influence the structures of the middle layer. For example: it is in charge of joining the iris with the choroids, it is the one that produces the acidic humor of the eyeball and it is the one that provides the process of accommodation of the lens.

3. Inner layer of the eye

Also known as posterior cavity, is what you can find the end of the road and takes care of the visual functions.

3.1. Aqueous humor

As its name implies, it is a clear aqueous liquid rich in vitamin C, glucose, lactic acid and proteins. That both the internal cavity and the anterior cavity are presented. Its main function is to oxygenate and nourish the cornea and lens.

There needs to be a delicate balance between the production and output of aqueous humor, since an excess of this inside the cornea can cause high intraocular pressure and cause diseases such as glaucoma.

3.2. Vitreous humor

On the contrary, this is actually a transparent fabric with a gelatinous texture that is responsible for protecting the eye from possible impacts. It occupies two thirds of the ocular structure as it is found throughout its interior.

3.3. Retina

It is located in the deepest part of the eyeball and occupies the function of visual capacity, including its acuity and the discrimination of the details of objects. Therefore, both its structure and its role is complex. It is a photosynthetic membrane, so it is the place where light is transformed into energy to be carried to the nervous system through the optic nerves.

It has cells that are sensitive to light (rods and cones) known as photoreceptors. Curiously, there are only 3 cones and they are responsible for the perception of color, but thousands and thousands of rods which are responsible for producing black and white tones and adapting our night vision, therefore, they are more sensitive.

Care for our eyes

It is important that we have a routine of care for our eyesso that they can maintain their health and optimal function for a long time. It is normal that over time, the visual capacity wears out, but if we subject our eyes to certain activities we can accelerate this degeneration earlier than normal.

1. Exposure to light

Excessive exposure to light is one of the most common causes of eye disease, discomfort, and deterioration of eye quality. Since the structures are overworking in the face of a luminosity difficult to regulate for a long time.

So it is necessary that you avoid spending too much time in front of your computer or any electronic device, do not look directly into the light out of the sun, going outside on a very sunny day without sunglasses, and dimming artificial lights in a small space.

2. Reduce reflection

The reflection of light on the natural lens or on the glasses also causes eye ailments such as headaches, a feeling of heaviness or eye swelling, irritation and dryness. That, if not treated in time, can lead to major complications over time, such as blurred vision or loss of focus.

So make sure to reduce the brightness of your electronic devices as much as possible so that they adapt to your field of vision and to the ambient brightness, opt for night mode if you read at night and put blue light filters on them during the day. Also be sure to ask for anti-reflective lenses in your glasses when you go to your optician, to avoid the reflection of light on the lenses.

3. Strain your eyes

This occurs when we try to focus the eye as much as possible to a point that causes discomfort. For example, when reading small print, reading on a bright screen, or on the contrary, doing activities without the adequate amount of light. So always try to make the most of natural daylight and don't keep working in the dark.

4. Take care of your sugar

Sugar levels are closely related to the health and functionality of the eye, remember that the Aqueous liquid has glucose and having diabetes or insulin problems can affect visual quality with the passage of weather. Influencing the appearance of cataracts.

5. Nurture yourself

It is important to consume nutrients that benefit eye health, such as foods rich in vitamins C and A, minerals that help protect them from UV rays and proteins that boost the immune system to prevent disease and discomfort eyepieces. For example: fruits of green, yellow and orange tones, vegetables rich in beta-carotene, dairy products, eggs and white meats.

6. Have a regular eye checkup

It is always important to visit an ophthalmologist at least once a year to check the health of our eyes. In this way we can be prevented from natural disasters, recommended treatments or tips to reduce their appearance.

In the same way, if they have glasses indicated by a specialist, you should have a regular check-up to evaluate the quality of the lenses and the evolution of your improvement.

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