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59 Cards in this Set
- Front
- Back
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Cornea |
Clear front window of the eye. Transmits & focuses light into the eye |
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Iris |
The colored part of the eye. The iris helps regulate the amount of light that enters the eye |
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Lens |
The transparent structure inside the eye that focuses light rays onto the retina |
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Macula |
Small area in the retina that contains some light sensitive cells. Allows to see fine details clearly |
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Optic nerve |
Nerve that connects eye to the brain. Carries the impulses formed by the retina to the brain, which interprets images |
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Pupil |
Dark center. Determines how much light is let into the eye. It changes size due to the amount of light available. |
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Retina |
Nerve layer that lines the back of the eye. Senses light and creates impulses that are sent through the optic nerve to the brain |
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Vitreous |
Clear jelly like substance that fills the middle of the eye |
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Sclera |
White part of the eye. Blood vessels are present to give blood and nourishment |
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Extraocular eye muscles {EOMS} |
6 EOMS attached helps eye have full range of motion. Hold eye in position |
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What's the eyeball also called |
Globe |
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What is it called when the eye(s) are misaligned |
Strabismus |
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What is double image |
Diplopia |
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What and where is the bulbar conjunctiva |
Mucous membrane it covers the sclera (white part of eye) |
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What is the function of the bulbar and palpebral conjunctiva |
They line the eyelids so objects(contacts) can't disappear behind the eye |
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What is the episclera conjunctiva |
Rich in blood vessels nourish underlying Sclera |
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Functions of Cornea |
- 2/3 of focusing power - strongest focusing power and thinnest part is the center - 5 layers, only one who can regenerate is the outermost layer (epithelium) |
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What's the part of the cornea that can regenerate cells & where is it located |
The epithelium Outermost layer of the cornea |
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What are the 2 segments inside the eye |
Anterior segment - divided into two chambers •anterior & posterior
Posterior segment |
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What is the anterior(front) chamber filled with |
Aqueous - area providing nutrition to areas lacking blood vessels (crystalline lens and cornea) |
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What does the iris Separate |
The anterior chamber from the posterior chamber |
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The bony orbit surrounding the globe is made of how many different bones |
7 |
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The size of the pupil adjust according to what? |
The level of light & accommodation (focusing) |
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What does the pupil use when it is adjusting to light and accommodation? |
Iris sphincter and dilator muscles |
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What chamber is the crystalline lens located |
The posterior chamber |
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What are the very thin fibers that the crystalline lens is suspended by? |
Zonules |
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What muscle are the Zonules attached to |
The ciliary muscle |
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What does the ciliary muscle do? |
Contracts and dilates to adjust the power of the lens to focus from far to near or vice versa |
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What is presbyopia |
It happens around 45+ years old, experience difficulty with near focus. Distance vision remains the same. |
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What is a cataract |
Clouding of the normally clear lens tissue. Causes decreased vision |
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What does the posterior segment consist of |
Vitreous, posterior sclera, choroid, and retina |
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What are the two photoreceptors in the eye |
Rods & cones |
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When the eyeball grows (elongate) what does it cause |
Nearsightedness aka Myopia |
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What are the function(s) of rods |
They function is dim lighting at night. They have no color reception |
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What are the function of cones |
They function in daylight conditions. The macula, is aligned with central line of sight has a high concentration of cones. Able to see great detail clearly. |
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What does the optic never(disk) lack? |
Photoreceptors, source of physiologic blind spot -15 degrees temporal to fixation just below horizontal midline |
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Where does vision begin |
Occipital Cortex in the posterior aspect of the brain |
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How many cranial nerves(CN) do humans have |
12 |
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How many CN affect vision |
7 (CN II - CN VIII) |
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What CN is responsible for sighg |
CN II |
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What CN(s) are responsible for innervating extraocular muscles |
CN III - CN IV - CN VI |
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What CN provides sensation of touch |
CN V |
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What CN provides reflex tearing and blinking |
CN VII |
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What is myopia |
Nearsighted |
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What happens when there is damage to a specific part of CN VIII |
Can result in nystagmus (rhythmic, involuntary eye movement) |
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When eyes are shorter it causes |
Farsightedness aka hyperopic |
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What is hyperopic |
Farsighted |
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Why do the eye lids close? |
-when lashes sense danger -when the eye sees a threat approaching -spread tears across the eye |
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What produces watery part of tears |
Lacrimal gland |
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Where is the lacrimal gland located |
Above eye toward outer edge under the brow |
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What is the function of puncta |
To drain tears when they are pushed across the eye toward the nose |
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What's is called when eyes maintain alignment |
Fusion |
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What are the three degrees of Fusion |
- image from one eye is superimposed over the image from the other eye - flat-fusion and a two dimensional image is formed - provides binocular depth perception |
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What is accommodation |
Ability of the eye to increase its focusing power for close objects. Also plays a role in depth perception |
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What is accommodation |
Ability of the eye to increase its focusing power for close objects. Also plays a role in depth perception |
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What is refractive error |
Lack of clear focus |
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What is accommodation |
Ability of the eye to increase its focusing power for close objects. Also plays a role in depth perception |
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What is refractive error |
Lack of clear focus |
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What are the two most common refractive errors |
- astigmatism • causes object of focus to be blurred - myopia • nearsightedness, distant vision to be blurred |
