human vision & optical systems
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
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light enters your eye through the _______ | pupil
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surrounding the pupil is a coloured muscle calle the _______ | iris
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the iris's job is to: | change the size of the pupil so the right amount of light will go in
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when it is dim, the iris _____ | dilates (expands)
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when it is bright, the iris ________ | contracts
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covering iris and pupil is the __________ | cornea
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cornea is: | a transparent tissue that lets light through but holds the eye together
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white part of eye is called the _____ | sclera
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behind the pupil is a ____________ that is flexible enough to change its shape | convex lens
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light rays pass though the lens and focus onto the screen at the backk of the eye, called the _____ | retina
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cells in the retina convert the light rays into electrical signals which are sent to the brain through the: | optic nerve
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as light rays contact the eye...: | the curved cornea causes them to refract so that the image can form on the retina
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the ______ is adjusted by muscles to do the final bit of focussing so that the image iwll form at just the right distance to appear on the retinca | lens
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the _________ does most of the focussing and the _________ does the rest of the focussing | cornea, lens
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if the object is far away, the lens is _________ | thinner
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if the object is close, the lens is _______ | thicker
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Where the optic nerve enters the retina is a small area where there are no light-sensing cells, called the: | blind spot
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_____________ are used to detect shades of light and dark. In low light, these cells are the main ones we use to see | Rod cells
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__________ detect colour. There are three types, which detect primarlily the three primary colours, red, green, and blue (as well as their corresponding secondary colours). | Cone cells
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In normal vision, the muscles change the shape of the _____ so that light from near and far objects focuses in the right place -on the retina | lens
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If a person is near-sighted, they see near objects fine but have difficulty focussing distant object. This is normally because: | the eye has become elongated, so the light rays from distant objects converge in front of the cornea
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Near-sightedness is fixed with: | a concave lens
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Far-sightedness is fixed with: | a convex lens
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If a person is far-sighted, they see distant objects fine but have difficulty focussing nearby objects. This is normally because: | the eye has become shorter, so the light rays from distant objects do not converge in time they reach the cornea
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when people get older, people usually get: | near-sightedness
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when people get older, people have eye problems because: | the muscles are weaker
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If a person has astigmatism, the __________ has a distorted shape so that it's images are focussed on more than one place on the _____________ | cornea,retina
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astigmatism is corrected with: | a special kind of glasses or contact lenses
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blindness | vision problem (no light, no colour (or just certain colours), any type of vision problem)
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To hide a column, click on the column name.
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You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
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Created by:
jlarose
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