How Does the Human Eye Work

The human eye functions like a light sensor. It gives man the ability to perceive the world around and observe much more than he can with the other four senses. The organ is put to optimum use throughout an entire lifetime for depth perception, to facilitate better movement in the immediate environment. The eyes help us to interpret colors, shapes and dimensions. This feat is achieved by processing the light emitted by objects around.

Parts of the Human Eye:

The anatomy of the human eye functions around an intricate system that comprises a number of independent and dependent parts. Collectively, the anatomy is responsible for capturing light reflected off objects in the surrounding, and generating images. The different parts of the human eye include:

• Anterior and Posterior Chambers or the space between the cornea and iris.
• Aqueous humor, a fluid that provides the cornea and lens with nutrients and oxygen.
• Canals of Schlemm, located around the iris, to facilitate the draining of aqueous fluid.
• Choroid, a layer of blood vessels between the sclera and retina.
• Ciliary body, the region where the aqueous humor is produced.
• Ciliary muscle, responsible for changing the shape of the lens for distance vision.
• Conjunctiva, a clear membrane in front of the eye and inner eyelids that produces mucous to lubricate the eye.
• Cornea, a dome-shaped surface that is the real optical system.
• Crystalline lens positioned behind the cornea, to maintain image-focus on the retina.
• Eyeballs in both eyes that offer binocular vision, by fusing images in the visual cortex.
• Eyelashes and eyebrows with protective hair.
• Eyelids to lubricate the eyes and keep them moist and clean.
• Eye sockets or cone-shaped cavities that protect the eye.
• Fovea, an indentation in the macula, responsible for highest visual acuity.
• Lacrimal gland or tear duct to prevents the cornea from becoming dehydrated.
• Lacrimal sac responsible for draining tears and debris from the eye.
• Iris, a ring of muscle fiber behind the cornea that responds to the brightness of surrounding light.
• Macula, a part of the retina responsible for central vision.
• Optic disk, a spot on the retina that creates the 'blind' spot.
• Optic nerve, a nerve fiber network that connects the eye to the brain.
• Six orbital muscles responsible for eye movement.
• Photoreceptor cells in the retina that send electrical signals to the brain.
• Pupil, responsible for enabling light to pass through.
• Retina, the eye film that converts light rays into electrical signals.
• Retinal pigment epithelium, a layer of cells between the retina and choroid that absorbs scattered and reflected light.
• Sclera, the white eye wall that uses internal fluid pressure to maintain eye shape.
• Visual axis, an imaginary line that facilitates the generation of a 'fixation' point.
• Vitreous cavity, the space between the lens and retina.
• Vitreous humor, a jelly like liquid that fills the eye.
• Zonules or string like fibers that hold the eye lens in position.

How Does the Human Eye Work?

Light waves from an object are reflected on the pupil through the cornea. The pupil constricts to accommodate the required light response for optimum vision. The bent light waves are reflected on the crystalline lens and nodal point, located behind the eye lens surface. Here, the image is reversed and inverted, before passing in 'clear focus' on to the retina. The retina registers tiny photons of light and turns light impulses into electrical signals. These signals are sent via the optic nerve, to the occipital cortex. Here the electrical signals are interpreted as a visual image.

The human eye is a vital organ of vision that is critical and essential to routine activities. It bears a direct impact on developmental learning, communication, and the overall quality of life. It is important to ensure that eye health is maintained at all times. Eyes are super-sensitive and hence, you need to avoid rubbing them indiscriminately. The use of eye protection gear when outdoors, a balanced diet comprising plenty of fresh fruits and vegetables and proper lighting help to maintain the health of these light-sensors.