Human eye
The human eyes are the sensory organ that allows you to see. Your eye captures the light around you and sends the signals to the brain in the form of the brain creating the vision.
Human eyes are one of the most important and most complex sensory organ that we human have. Eyes capture light from outside the world and convert it into image we see. Whereas it sends signal to brain out the information about outside the world. Your brain doesn’t have sensory ability to it’s own it needs your eyes to gather information around you.
In the world, most of the people are born with two eyes and when worked together, they give you wide view of about 135 degrees tall and 200 degrees wide. When both of your eyes work correctly the give you a 3D vision and depth perception.
Human eyes help in feeding information to the brain from the outside world. Basically, the eyes do the physical part of seeing things around you and send signals to the brain to process them. It builds pictures you see, captures visible lights, and converts them into a way that the brain understands.
Human eyes work pretty much the same as a camera; they help visualize objects and also help with colour, depth, and light perception. The eye helps us see objects when light comes from outside. Human eye is almost 2.3 cm in diameter and roughly looks like spherical ball filled with some fluids. Basically sight is the process done by eyes but vision is the process which starts with sight and ends with what your brain understand from what your eyes see.
Anatomy of the human eye
1. Retina
The retina is a light-sensitive thin layer of tissue present at the back of the eye that converts light into an electric signal to the brain. The cells that help light to convert into electric signals are called photoreceptors.
2. Lens
Lens are the clear inner part of eye. It is transparent and can be replaced if needed. The lens work together with the cornea and retina, it focuses light rays onto the retina. It usually gets weaken with age, resulting in need of reading glass or power glasses.
3. Sclera
The white outer covering of the eye generally forms the shape and structure of the eyeball. It is a tough white layer that protects your eyes, surrounding their
4. Iris
Iris is responsible for the colour of your eyes. It contain the muscle that control the size of the pupil. Iris Helps to regulates the amount of light that enters into the eye. It manage the pupil contraction, when there is bright light iris closes the pupil and when there is low Light iris open up the pupil to manage light that enters the eye.
5. Macula
The macula is a pigmented oval-shaped area located in the centre of the retina. Macula is the key to your vision and is mainly responsible for the centre of your vision. In the macula, there are light-sensitive cells that allow us to see details clearly. Macula getting weak as you grow older is common.
6. Cornea
Cornea is the clear front window of the the eye, which focuses and transmits light into your eye. It works as a windshield to protect inside of your eye. It is shaped like a dome and works to bend light into the eye for better focus. Your tear works as a lubricate for the cornea, as it helps to bend light that enters your eye. Cornea is the front transparent part of sclera.
7. Optical nerve
Optical nerve is a group of million nerve fibers that carries visual message to your brain. Its connects your brain to your retina. Basically it works as a data cable that connects your retina to your brain, which carries signal from your eyes, connecting multiple parts of your brain. Electric signals from retina are carried to your brain from optical nerve, where your brain convert those electric signals into images.
8. Choroid
A thin layer of tissue that has blood vessels to the back of the eye is located between the sclera and retina and is filled with blood. The choroid has the major function of supplying oxygen and nutrients to the outer retina, as well as thermoregulation, light absorption, and modulation of intraocular pressure. It maintains the temperature and volume of the eye; the choroidal circulation accounts for 85% of the total blood flow in the eye and is a high-flow system proportional to low oxygen content.
9. Fovea
The fovea is located in the middle of the macula lutea of the retina. It is mostly responsible for the sharp central vision. The fovea is about 0.35 mm in diameter. It is small in size and has a flat spot located in the centre of the posterior portion of the retina.
10. Pupil
Light enters through the small opening called the pupil. It is located in the iris and is small in size, whereas it’s size is controlled with the help of iris. Pupil is like a small black dot inside iris that works like an adjustable window. It controls how much light enters into your eyes, if it,s too bright is will get small in size and if it will be low light then it will increase it size for more light.
Function of the human eye
The human eye basically works as a camera that captures the light and passes it through different parts of the eye to convert it into an image.
- First, Light reflects from the object we are looking at.
- Then, rays of light enter the eye from the front of the eye (cornea).
- Light then passes through a watery liquid called aqueous humour to the pupil and reaches the lens.
- Then, the lens and cornea help light rays pass to the back of the eye (retina), where the lens can change its thickness to adjust according to the light.
- On its way to the retina, light passes through a thick liquid called the vitreous humour. Meanwhile, vitreous humour helps the eyeball maintain its shape.
- When light reaches the retina, it translates the light rays into electric impulses that transfer from the optical nerve to the brain to understand.
- At last, the image is formed by the millions of cells, and they relay the signal to the brain via the optic nerve. The image which is made is usually upside down, but the brain corrects the phenomenon, and we see what we see.
Conclusion
Human body have many sensory organ one of them is eye which helps with the vision part. Eyes are one of the very sensitive organ. Human eye helps to see around. It is a complex organ with 1 million nerves. It helps to intake light and convert it into the way b rain understand and we see what we see.
