Special Senses II Flashcards
What are the three layers of the eye
Sclera, choroid, retina
What is the sclera
White part of eye
What is the transparent part of the eye
The cornea
What is the colored part of the eye
The iris
What does the iris control
The amount of light passing through into the eye (size of pupil)
What is the choroid
The vascular middle layer of the eye
What is accommodation
The process of the lens changing shape to view objects at different distances
What is the purpose of the ciliary body
The ciliary body pulls on the lens to change its shape
What is refraction
The bedding of light to focus it on a point in the retina
How are the cornea and lens involved in refraction?
The cornea and lens are important for focusing (bending) the light onto the retina
What happens when the eyeball is too short
You are farsighted (hyperopia)
How do you correct farsightedness
Convex lenses
What happens if the eye is too long
You are nearsighted (myopia)
How do you correct nearsightedness
concave lenses
What is presbyopia
Age related far sightedness
What is astigmatism
Defect in cornea that causes the bending of light to be distorted
Where do cataracts occur
Lens
Why do cataracts occur
Proteins cluster together in the lens
Which structure is light sensitive and contains photoreceptor cells
The retina
What is considered the ‘physiological blind spot’ of the eye?
The optic disk, where the optic nerve attaches to the retina. There are no photoreceptor cells here
What is the fovea?
The focal point where the light hits on the retina (has the most photoreceptor cells)
What is the macula in the eye
Part of the fovea
What is the difference between rod and cone photoreceptors?
Rods=monochromatic
Cones=Color vision
What are the cavities and fluids that are contained in the eye called?
Vitreous Humor- fills space behind the lens, provides intraocular pressure to hold the retina and lens in place.
Aqueous Humor-Fills the space behind the cornea and in front of the lens
What is glaucoma
Elevated intraocular pressure
What is age related macular degeneration
A severe and irreversible loss of central vision due to the destruction of the macula (it’s like having a black spot in the center of your vision). There is no effective treatment.
What is diabetic retinopathy
damage to blood vessels bleeding into the retina
What does the visual field look like for someone that has cataracts?
Dimmed vision and blurry
What does the visual field look like for someone that has glaucoma
Everything blacked out except for small hole of vision
What does the visual field look like for someone with macular degeneration?
Distorted image
What does the visual field look like for someone with diabetic retinopathy
black spots in vision
What are three accessory structures of the eye?
1.Eyelid
2.Lacrimal apparatus (lacrimal gland, canaluculi and lacrimal duct)
3.Muscles
What does the eyelid do?
Protects and moistens eye
What does the lacrimal apparatus do?
Produces, distributes, and removes tears
What do the muscles of the eye do?
They move the eye in every direction
