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| 1. |
Explain construction and working of human eye |
| Answer» The light coming from an object enters the eye through cornea and pupil. The eye lens converges these light rays to form a real, inverted and diminished image on the retina. The light sensitive cells of the retina gets activated with the incidence of light and generate electric signals. These electric signals are sent to the brain by the optic nerves and the brain interprets the electrical signals in such away that we see an image which is erect and of the same size as the object. Before we go into the defects of vision let us be familiar with the terminology used by the ophthalmologists like least distance of distinct vision, far point and power of accommodation of the eye.\xa0Functions of the Parts of Human EyeScleraProtects and contains internal partsCorneaCornea is responsible for maximum refraction of incident lightAqueous HumourPrevents collapse of the eye due to atmospheric pressure changesIrisIris controls the light entering the eye by adjusting the size of pupilCrystalline LensFocuses the light reflected by objects on the retina.Ciliary MusclesAlter focal length of the crystalline lensRetinaReceives optical image and converts it to electrical impulsesVitreous HumourMaintains the shape of the eyeOptic NerveCarries electrical impulses to the brain. Brain interprets these impulses and produces the sense of vision. | |