Term
| What are the three primary layers of the eye? |
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Definition
| Fibrous, vascular, and nervous tunics |
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Term
| What are the two types of photoreceptor? |
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Definition
|
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Term
| What are rods primary purpose? |
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Definition
| Sensing in dim light and twilight |
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Term
| What are the cones primary purpose? |
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Definition
|
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Term
| What photoreceptor is best for detailed vision? |
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Definition
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Term
| How many photoreceptors are there in one retina? |
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Definition
| 120 million rods, 6 million cones |
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Term
| What is the macula of the retina? |
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Definition
| The central portion of the retina responsible for detailed vision |
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Term
| Where in the retina are rods predominantly found? |
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Definition
|
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Term
| Where in the retina are cones predominantly found? |
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Definition
| Macula of the central retina |
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Term
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Definition
| The center of the macula with the highest concentration of cone photoreceptors |
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Term
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Definition
| Where the optic nerve enters/exits the eye |
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Term
| Are there photoreceptors in the optic disc? |
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Definition
| No, this is commonly referred to as the 'blind spot' in each eye |
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Term
| What are the three primary chambers of the eye? |
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Definition
| Anterior chamber, posterior chamber and vitreous chamber |
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Term
| What is contained in the vitreous chamber? |
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Definition
| The vitreous humor, the large gel like substance which helps give the eye its shape |
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Term
| What is the clear front portion of the eye? |
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Definition
|
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Term
| What are the 5 layers of the cornea? |
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Definition
| Epithelium, Bowmans membrane, stroma, Descements membrane and endothelium |
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Term
| Of the 5 layers of the cornea, which is thickest, taking up 90% of the corneas thickness? |
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Definition
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Term
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Definition
| The opening in the iris that allows light to enter the vitreous chamber |
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Term
| What controls the size of the pupil? |
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Definition
|
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Term
| What is the colored part of the eye called? |
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Definition
|
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Term
| Whata re the two main muscles in the iris? |
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Definition
| dilator and sphincter muscle |
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Term
| What is the iris dilator muscle's shape and function? |
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Definition
| Like spokes on a bicycle wheel, they open the iris when contracted |
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Term
| What is the iris sphincter muscle's shape and function? |
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Definition
| Ring like, it functions like a draw string on a hoodie to close the iris when contracted |
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Term
| What is the typical range of pupil size the iris can accommodate? |
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Definition
| 2mm to 8mm typically, though 1mm to 10+mm are possible for some people |
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Term
| What is the crystalline lens? |
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Definition
| A clear collagen lens that focuses light entering the eye |
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Term
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Definition
| The focusing capacity of the crystalline lens to change focus from distance to near |
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|
Term
| What structures hold the crystalline lens in place? |
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Definition
|
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Term
| How do zonules help with accommodation? |
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Definition
| They control the tension on the crystalline lens, tailoring its shape to the desired power |
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Term
| What is the ciliary muscle? |
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Definition
| The muscle that controls accommodation |
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Term
| What happens when the ciliary muscle is contracted? |
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Definition
| Tension on the zonules decrease and the crystalline lens thickens allowing the eye to focus closer |
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Term
| What happens when the ciliary muscle relaxes? |
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Definition
| Tenion in the zonules increases, thinning the crystalline lens allow the eye to focus further away |
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Term
|
Definition
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Term
|
Definition
| Where the eyelids meet near the nose |
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Term
| What is the lateral canthus? |
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Definition
| Where the eyelids meet towards the ear |
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Term
| What are meibomian glands and where are they located? |
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Definition
| Oil glands in the eyelids |
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Term
| Where is the lacrimal gland? |
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Definition
| Above the outer aspect of the eye inside the orbit |
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Term
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Definition
| The limit of the 'pouch' that attaches to the front of the eye, it is why objects can't go completely behind the eye |
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Term
| What is the lacrimal puncta? |
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Definition
| A set of drains in the upper and lower eyelid that carries tears into our nasal cavity |
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Term
| How does the cornea 'breathe' or get oxygen? |
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Definition
| As it is clear, it has no blood supply and gets oxygen directly from the air that contacts the front of our eye |
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Term
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Definition
| The ring shaped junction where the iris (colored part) and sclera (white part) meet |
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Term
| What is the strongest layer of the eye? |
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Definition
|
|
Term
| How many extra ocular muscles or oculomotor muscles are there? |
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Definition
|
|
Term
| What is the lateral rectus? |
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Definition
| The eye muscle that pulls the eye out toward the ear |
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|
Term
| What is the superior rectus? |
|
Definition
| The muscle that pulls the eye upwards |
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|
Term
| What is the inferior rectus? |
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Definition
| The muscle that pulls the eye downwards |
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|
Term
| What is the inferior oblique? |
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Definition
| Rolls the eye, looks up and to the side |
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|
Term
| What is the superior oblique? |
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Definition
| Rolls the eye, looks down and to the side |
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Term
|
Definition
| The 'pulley' that the superior oblique muscle slides through |
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Term
|
Definition
| An eye that properly focuses light, they will not need glasses for distance |
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Term
|
Definition
| The loss of near focusing power that leads to the need for near adds, progressives, bifocals |
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Term
|
Definition
| The crystalline lens hardens and can no long be squished into a shape that focuses near |
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Term
|
Definition
| Nearsightedness, will need glasses for far away |
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Term
|
Definition
| Farsightedness, will need glasses to see comfortably at near and often far if severe enough |
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Term
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Definition
| When the eye focuses light to two different points, leading to ghosting or doubling of the image |
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|
Term
| What distance does astigmatism effect in vision? |
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Definition
| All, a patient with astigmatism will have it up close and far away |
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