THE HUMAN EYE

The human eye is a vital and important organ in the body. It is the organ for seeing and located around the head. It is found in all animals and vertebrates. The eye is spherical in shape.
The eye is made up of tissues, muscles and several protective structures which are:
[image source: Google]
•Eye socket
•Eyelids
•Eye lashes
•Tear glands
•Conjunctiva
It is housed in a protective cavity in the skull called the eye socket.
MUSCLES OF THE EYES
[image source: Google]
The eyes is attached to the socket by muscles which serves to hold it firmly in a place and enable it to rotate freely upward, downward and sideways without moving the head. The muscles are listed below;
•Trochlea
•Levator
•Frontal bone
•Superior obligue
•Optic nerve
•Lateral rectus
•Inferior rectus
•Maxilla
•Inferior Obligue
The black big ball in the eye is called the #Iris. The pupil is located in the Iris. They control the amount of light passing through the eyes. Surprisingly, when bright light shines on the eyes, circular muscles of the Iris contracts, making the pupil small, thus, reducing the amount of light entering the eyes.
[image source (Iris): Google]
FORMATION OF IMAGES
The ability to see involves a lot of processes. The image or the object viewed must first be formed in the #Retina. The stimulus of light reflected from the figure must then be reconciled by sensory cells in the retina depending on the intensity of the light. The impulse of this stimulus must be transmitted through the #OpticNerve to the optic lobe of the brain which correctly interpreted the image.
HEALTH PROBLEMS ASSOCIATED WITH THE HUMAN EYES
There are lot of health related issues associated with the eyes. These conditions could be caused by careless attitude, bacterial infections,...etc. Some other defects of the eyes could be caused by old age. The underlisted are some of the diseases of the eyes:
•Myopia
•Hypermetropia
•Presbyopia
•Astigmatism
•Colour Blindness
•Night Blindness
•Cataracts
•Conjunctivitis
•Floaters
•Flashes
[image source: Google]
SIZE OF THE HUMAN EYES
The transverse size of a full grown adult's eyes is 24.2mm and the sagittal size is 23.7mm with no significant difference between sexes age. The eyeball grows rapidly and by age thirteen (13), the eye has attain full size.