Term
| How dose an eye focus an image? |
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Definition
| Both the and the camera have a lens to focus an image onto a surface for recording. In the eye this surface is the retina. In the camera,the distance between the film and the camera lens is adjusted to bring the picture into focus before it is recordedon the film |
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| When the ciliary body contracts, the lens becomes rounder in a process known as accommodation to permit near vision. With relaxation the lens thins out to accommodate focusing on distant objects. |
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Term
| How does the eye control light? |
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Definition
| The aperture of the camera is similar to the iris of the eye;the size of their opening is ajusted to allow varying amounts of light to enter. The iris is the colored circular muscle that surrounds the center opening called the pupil |
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Term
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Definition
| A mucous membrane called the conjunctiva lines the inner surfaces of the eyelids and covers the anterior sclera surface of the eye |
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Definition
| Where the optic nerve exits the rentia, there are neither rods nor cones, so this area is referred to as the optic disc or blind spot |
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Definition
| This gradually developing opacity(cloudiness)of the lens |
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Definition
| Amblyopia is known as lazy eye because it causes the turning eye to become "lazy" |
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Definition
| This condition is caused by inflammation of the conjunctiva.It usually begins in one eye,spreading rapidly to the other from contamination by a wash cloth or by the hands |
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Definition
| This condition of excessive intraocular pressure results in atrophy (wasting away) of the optic nerve |
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Definition
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Definition
| This a condition characterized by inability of the lens to accommodate for near vision |
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Definition
| Is drooping of the upper eyelid |
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Term
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Definition
| One eye deviates with the gaze being abnormally inward or outward ,higher or lower then the other eye |
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Term
| What is the eustachian tube? |
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Definition
| The middle ear is connected by the means of the eustachian tube to the throat |
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Term
| What is the semicircular canals? |
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Definition
| These structures are responsible for maintaining equilibrium.Inside the canals hair-like nerve cell receptors are embedded in a gelatin-lke material.When the head moves the material pushes against the receptors which transmit to the brain the change in position |
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