Term
How does the snellen eye chart work? (20/x) |
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Definition
the smallest line of the chart seen by the patient at 20 feet can be seen by a normal individual at the distance given in the denominator |
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Term
Are optical vision problems correctable or uncorrectable? |
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Definition
correctable, they have to do with images not being focused on the retina |
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Term
Are retinal and retro-orbital vision problems correctable or uncorrectable? |
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Definition
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Term
A lesion of the optic nerve causes what? |
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Definition
Total blindness on the effected side |
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Term
A lesion at the optic chiasm causes what? |
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Definition
Inability to see in the lateral field of vision (tunnel vision)= bitemporal hemianopsia |
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Term
What does a lesion of the optic tract cause? |
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Definition
Inability to see to the objects on the contralateral side of the head (homonymous hemianopsia) |
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Term
What is the optic radiation? What does a lesion there cause? |
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Definition
The extension of the optic tract in the occipital lobe. Causes homonymous hemianopsia just like a lesion to the optic tract does |
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Term
What does homonymous mean in relation to visual defects? |
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Definition
the defect occurs in the same portion of the field for each eye |
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Term
The region of the eyeball where the optic nerve enters is called what? |
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Definition
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Term
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Definition
optic disk swelling often caused by increased intracranial pressure |
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Term
Which artery supplies the eye? This is the first branch of what major artery? |
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Definition
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Term
The ophthalmic artery gives rise to what artery? Where does this branch to? |
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Definition
-Central retinal artery -has a branch to the upper half and lower half of the retina |
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Term
Loss of one of the branches of the central retinal artery causes what? |
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Definition
altitudinal scotoma (A localized defect in the visual field bordered by an area of normal vision) |
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Term
Transient loss of any part of a retinal artery is called what? |
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Definition
Amaurosis fugax (this is a TIA probably from the ICA) |
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Term
Which artery supplies the optic radiations? |
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Definition
the middle cerebral artery (the radiations pass through the parietal and temporal lobes) |
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Term
Which artery supplies the primary visual cortex? |
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Definition
the posterior cerebral artery? |
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Term
What is optic neuritis? What is it often related to? |
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Definition
-inflammatory demyelination of the optic nerve -often related to MS |
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Term
What are 4 clinical features of optic neuritis? |
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Definition
-eye pain (esp. on movement) -monocular vision problems -afferent pupillary defect -abnormal visual evoked potentials |
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Term
Is complete recovery common or uncommon with optic neuritis? |
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Definition
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