Term
| near point of accommodation |
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Definition
| the closest distance at which an object can be focused |
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Term
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Definition
| the region of the optic disk that lacks photoreceptors |
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Definition
| the sharpness of vision, usually tested with a snellen chart(printed card with letters and numbers of decreasing sizes) |
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Definition
| the unequal curvature of the refractive surfaces of the cornea and/or lens |
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Term
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Definition
| result from the bleaching or light adaptation of stimulated cones. the light adapted cones cannot initiate impulses, only the unadapted cones are responding |
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Definition
| results when a person lacks one of the three cone types(red, blue, or green). they percieve colors differently and/or cannot see the color |
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Definition
| the sensitivity. a measure of how well a person hears. |
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Term
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Definition
| the ability to determine the specific location of a sound source. |
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Term
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Definition
| test that uses a tuning fork to detect any form of deafness. the tone will seem louder to an ear with conductive deafness and seem softer to an ear with neural deafness |
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Definition
| a test that compares the conduction in air to the conduction in bone with a tuning fork that causes the temporal bone to vibrate and bypass the normal conduction pathway |
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Definition
| the rapid, involuntary movement of the eyes, resulting from the stimulation of the semicircular canals |
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Term
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Definition
| a test for the defective functioning of the vestibular nerve. caused by the continuing movement of the semicircular canals |
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Term
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Definition
| a state of physical balance. an interruption in equilibrium can be caused by a specific motion to each semicircular canal that still moves after the person has stopped |
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Definition
| the eyes inability to focus on near by objects due to the crystallization of the lens |
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Definition
| the condition of the eye where incoming rays of light reach the retina before they converge into a focused image. far sightedness |
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Term
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Definition
| a condition in which light is brought to a focus in front of the retina because the eye is too long. near sightedness |
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Definition
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Definition
| deafness associated with the loss of vibrational signals along the conversion of airborne sound waves to fluid vibrations |
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Definition
| where the transmission of sound waves to the inner ear occurs normally, but they are not translated into electrical signals properly so the auditory cortex is unable to perceive sound |
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Term
| major causes of conductive deafness |
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Definition
| problems in the outer or middle ear such as the build up of earwax, a ruptured eardrum or the accumulation of fluid as a result of an ear infection |
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Term
| major causes of sensorineural deafness |
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Definition
| a defect in the organ of corti, or the nerves that run from the inner ear to the brain, or damage to the auditory cortex itself |
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