Structure And Function Of Eye

Introduction
Because of the advancements in medical science, we can know much about the structure and function of human eyes. This knowledge helps us in understanding the pathophysiology of various ocular diseases and diagnosing them correctly. The information also helps in coming up with new treatment options for ocular diseases.

Structure Of Eye
The eye is one of the most complex organs with various functional parts. Some of the structures of eyes include:

Cornea: Cornea is the transparent tissue situated in the front of the eye. The cornea allows the light to enter the eyes. The cornea plays an important role to focus the light on the retina. Refractive errors such as short-sightedness and long-sightedness may develop if the light does not fall correctly on the retina.

Iris and Pupil: A circular ring like-colored structure just behind the cornea is the iris. The pupil is the central aperture present in the iris through which light enters into the eye. Iris controls the amount of light that enters as inappropriate light may lead to poor vision. If the environment is dark, the size of the pupil increases, allowing a large amount of light to enter the eye. In a bright environment, the amount of light entering the eye reduces because of the reduced diameter of the pupil. This is done with the help of dilator muscle and pupillary sphincter muscle.

Lens and Ciliary muscles: Lens is situated behind the iris, inside the eye. The function of the lens is to focus the light on the retina. It allows us to see near and distant vision by a process called accommodation. If the person looks at the near object, the lens gets thicker, while the lens gets thinner to focus on distant objects. This process of accommodation is done with the help of ciliary muscles that are connected to the lens. These muscles also keep the lens in position by giving it the necessary support.

Aqueous and Vitreous humor: The eye is divided into two segments, the anterior segment, and the posterior segment. The anterior segment extends from cornea to lens while the posterior segment extends from lens to retina. While aqueous humor is filled in the anterior chamber, vitreous humor is present in the posterior chamber.

Retina: Retina is an important part of the eye which is essential for vision. It comprises various photoreceptor cells called the rod and cone cells that sense the color and image of the object. Blood vessels are also present in the retina to provide essential nutrients. The macula, which is the central part of the eye, is responsible for visual acuity and contains a large number of photoreceptors.

Optic nerve: The optic nerve is the part of the nervous system .It carries the nerve impulses from retina to the brain for processing. The optic nerve of both the eyes meet at the optic chiasm. The optic chiasm is important for binocular vision and is also responsible for maintaining hand-eye coordination.

Function Of Eye
Our eyes function like a digital camera. The light enters the eyes through the pupil, while cornea helps in focusing the light onto retina. The light travels through the lens before falling on the retina. The photoreceptors on the retina sense the light and send the sensory signal to the brain through the optic nerve.

The binocular vision is because of the optic chiasma in the brain, the area where optic nerves of both the eyes meet. This area is present near the cerebrum and pituitary gland. Both right and left side of the brain receives information from both the optic nerves due to their crossover at the optic chiasm. Images formed on the retina are 2D which are converted to 3D by the brain.

If you have any problem with vision or feel that your vision is deteriorating, book an appointment with the best eye doctor or best eye consultant near you today.