Human eye is the most remarkable and most delicate optical instrument.
Principal. Its principal is simmilar to a photographic camera , it is far most delicate and perfect than the finest camera ever designed by human being ingenuity
Structure of human eye. The human eye consist of nearly spherical ball of about 2.5cm diameter.
Its outermost coating is made of a tough and opaque white substance known as SCLEROTIC. Sclerotic prevents the shape of eye and protect it against external injury .
Front portion of the sclerotic is transparent and slightly bulged outward and known as CORNEA . There is a layer of black tissue below the sclerotic and is called CHOROID. It serves to absorb any stray light and thus avoid blurring of image by reflecting from the eye ball.
In front of the eye , Choroid emerges into a colorful diaphragm known as IRIS with a hole in the middle called PUPIL. When we refer to the color of the eye we refer to the color of iris of the person. By means of involuntary muscles control, it regulates the amount of light entering the eye. In strong light, the pupil contracts so as to admit less light whereas in dim light it expends so as to admit as much light as required.
Behind iris is a crystalline lens with a jelly like layer. The layer is held in position with the help of CILIARY MUSCLES. The lens devides the eye ball into two chambers - the front chamber is called anterior chamber and the other between lens and retina called posterior chamber. Anterior chamber is filled with a fluid called AQUEOUS HUMOUR while the posterior chamber is filled with VITREOUS HUMOUR.
The innermost coating of eye , convering the rear of inner surface , is a very delicate membrane called the RETINA . It is richly supplied with blood vessels and nerve fiver and serves as a light - sensitive screen to receive the image . The sensation of vision in the retina is carried to the brain by a nerve called OPTIC NERVE. The most sensitive part of retina is known as yellow spot. It is a slightly raised portion with a slight depression known as the forvea centralis . The portion where the optic nerve enters the eye is totally insensitive to light and is known as blind spot
EYELIDS are provided to control the amount the light fallin on the eye Lids also protect the eye from dust.
If you have any problem just comment below and stay turned also visit our other site for amazing tricks
Principal. Its principal is simmilar to a photographic camera , it is far most delicate and perfect than the finest camera ever designed by human being ingenuity
Structure of human eye. The human eye consist of nearly spherical ball of about 2.5cm diameter.
Its outermost coating is made of a tough and opaque white substance known as SCLEROTIC. Sclerotic prevents the shape of eye and protect it against external injury .
Front portion of the sclerotic is transparent and slightly bulged outward and known as CORNEA . There is a layer of black tissue below the sclerotic and is called CHOROID. It serves to absorb any stray light and thus avoid blurring of image by reflecting from the eye ball.
In front of the eye , Choroid emerges into a colorful diaphragm known as IRIS with a hole in the middle called PUPIL. When we refer to the color of the eye we refer to the color of iris of the person. By means of involuntary muscles control, it regulates the amount of light entering the eye. In strong light, the pupil contracts so as to admit less light whereas in dim light it expends so as to admit as much light as required.
Behind iris is a crystalline lens with a jelly like layer. The layer is held in position with the help of CILIARY MUSCLES. The lens devides the eye ball into two chambers - the front chamber is called anterior chamber and the other between lens and retina called posterior chamber. Anterior chamber is filled with a fluid called AQUEOUS HUMOUR while the posterior chamber is filled with VITREOUS HUMOUR.
The innermost coating of eye , convering the rear of inner surface , is a very delicate membrane called the RETINA . It is richly supplied with blood vessels and nerve fiver and serves as a light - sensitive screen to receive the image . The sensation of vision in the retina is carried to the brain by a nerve called OPTIC NERVE. The most sensitive part of retina is known as yellow spot. It is a slightly raised portion with a slight depression known as the forvea centralis . The portion where the optic nerve enters the eye is totally insensitive to light and is known as blind spot
EYELIDS are provided to control the amount the light fallin on the eye Lids also protect the eye from dust.
If you have any problem just comment below and stay turned also visit our other site for amazing tricks
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