how are the vision defect caused? please tell me very very fast . it's very urgent.
Answers
Causes of blindness include macular degeneration, stroke, cataract, glaucoma, infection and trauma. Symptoms and signs may include eye pain, eye discharge, or the cornea or pupil turning white. Treatment of blindness depends upon the cause of the blindness.
and are as follows.
Explanation:The human eye is an impressive system for turning light rays into images. The light reflected by objects in the field of view first hits the cornea, which is protected by a clear tissue covering called the epithelium. The cornea is responsible for about 70% of the refraction or focusing of the light.
The human eye is an impressive system for turning light rays into images. The light reflected by objects in the field of view first hits the cornea, which is protected by a clear tissue covering called the epithelium. The cornea is responsible for about 70% of the refraction or focusing of the light.The light then passes through the pupil, i.e. the central opening in the iris, and reaches the lens. The lens does the final focus adjustment so that the light is bundled, i.e. focused, when it reaches the retina. At the retina, the light is translated into electrical impulses and sent to the optic nerve. The optic nerve takes these impulses to the brain, which translates them into images.
The human eye is an impressive system for turning light rays into images. The light reflected by objects in the field of view first hits the cornea, which is protected by a clear tissue covering called the epithelium. The cornea is responsible for about 70% of the refraction or focusing of the light.The light then passes through the pupil, i.e. the central opening in the iris, and reaches the lens. The lens does the final focus adjustment so that the light is bundled, i.e. focused, when it reaches the retina. At the retina, the light is translated into electrical impulses and sent to the optic nerve. The optic nerve takes these impulses to the brain, which translates them into images.If all goes well, the cornea and lens bundle the light rays exactly on the retina. This is what we call “normal vision.” Everything is in sharp focus at all distances.