Eye
- 1. The Human Eye Contents : 1. Location of eye 2. Structure of eye 3. Binocular vision
- 2. • The eyes are located in a deep protective bony cavities known as orbits. • The eye is hollow spherical in shape, about 2.5 cm In diameter and it’s weight is about 6 to 8 gms. • The eyes has two parts wall and contents. • The wall of eye is composed of three layers , 1. Outer fibrous sclera And cornea 2. Middle choroid 3. Inner retina
- 4. The cornea serves as a protective covering for the front of the eye and also helps focus light on the retina at the back of the eye. The pupil is the black dot in the middle of the eye. The iris—the circular, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye.
- 5. Behind the iris sits the lens. By changing its shape, the lens focuses light onto the retina. Through the action of small muscles (called the ciliary muscles), the lens becomes thicker to focus on nearby objects and thinner to focus on distant objects. The retina contains the cells that sense light (photoreceptors) and the blood vessels that nourish them. The most sensitive part of the retina is a small area called the macula. Each photoreceptor is linked to a nerve fiber.
- 6. The photoreceptors in the retina convert the image into electrical signals, which are carried to the brain by the optic nerve. There are two main types of photoreceptors: cones and rods. Cones are responsible for sharp, detailed central vision and color vision and are clustered mainly in the macula. Rods are responsible for night and peripheral (side) vision. Rods are more numerous than cones and much more sensitive to light, but they do not register color or contribute to detailed central vision as the cones do. Rods are grouped mainly in the peripheral areas of the retina.
- 7. The eyeball is divided into two sections, each of which is filled with fluid. The pressure generated by these fluids fills out the eyeball and helps maintain its shape. The aqueous humor, which nourishes the internal structures.It is filled with a watery clear fluid which is secreted by ciliary processes of ciliary body. The back surface of the lens to the retina contains a jellylike fluid called the vitreous humor. It is full of transparent fluid thick which is secreted by retina during development of eye .
- 8. Binocular Vision In many animals,due to the position of their eyes,They can see one set of objects from the left eye and an entirely different set of objects through the other.but in human beings,both eye focus on only one set of object .this characteristic vision is called as single binocular vision. It occurs when light rays from an object strike corresponding point .
- 10. Thank you Presented by:Mr.Hardikkumar.B.Prajapati B.pharm , student Smt.B.N.B.Swaminarayan pharmacy college, Salvav ,Vapi