Tag: human eye and its working

Aqueous humour is a transparent, gelatinous fluid similar to plasma. It is present between the lens and the cornea. It helps in protection of the eye, provides nutrition to the eye, and allows exchange of gases & other substances between the eye & air. It also helps in maintaining the pressure in the eye. Vitreous humour is also a clear gelatinous gel like fluid that fills the space between the lens and the retina. It helps in maintaining the shape of the retina by holding the retina in its place. The eyeball is approximately spherical in shape with a diameter of about 2.3 cm. The crystalline eye lens provides the finer adjustment of focal length required to focus objects at different distances and forms an inverted real image of the object on the retina.

Vitreous humour is a clear gelatinous gel like fluid that fills the space between the lens and the retina. It helps in maintaining the shape of the retina by holding the retina in its place. The crystalline lens helps in finer adjustments of focal length required to focus objects at different distances and forms an inverted real image of the object on the retina. Aqueous humour is present between the lens and the cornea and helps in maintaining the pressure in the eye

Iris is a dark muscular diaphragm that controls the size of the pupil. It is located behind the cornea.

Aqueous humour is a transparent, gelatinous fluid similar to plasma. It is present between the lens and the cornea. It helps in protection of the eye, provides nutrition to the eye, and allows exchange of gases & other substances between the eye & air. It also helps in maintaining the pressure in the eye.

The eye lens is made up of a fibrous, jelly-like material. Its curvature can be modified to change its focal length to some extent by the ciliary muscles. When the muscles are relaxed, the curvature decreases making the lens thin and the focal length increases. Similarly when the ciliary muscles contract the curvature of the eye lens increases making them thicker, this decreases the focal length of the eye.

Images formed on retina of human eye are real and inverted by the convex nature of lens in eye. 

Persistence of Vision is used in cinematography or movie projectors. Persistence of vision works because the human eye and brain can only process 10 to 12 separate images per second, retaining an image for up to a sixteenth of a second. If a subsequent image replaces it in this period of time it will create the illusion of continuity. Animation works by using an optical illusion. By presenting a sequence of still images in quick enough succession, the viewer interprets them as a continuous moving image. This is the same principle that enables live action film making and projection to work. Film theorists often refer to this illusion of movement as the persistence of vision.

Retina is a part of human eye which act as a screen with photo receptor where image will be formed and signal will be sent to the brain.

The least distance of distinct vision for a normal eye is 25 cm.