Visual Optics

Question 1

Focal length

Answer 1

distance behind a convex lens at which parallel lights rays converge

Question 2

If light sources is moved [closer/farther], point of focus moves further behind lens

Answer 2

closer

Question 3

Diopter =

Answer 3

1 / focal length

Question 4

Unit describing refractive power of a lens

Answer 4

diopter

Question 5

Thickening the lens [increases/decreases] focal length

Answer 5

decreases

Question 6

Two types of fibers associated with ciliary muscles

Answer 6

1) meridional fibers

2) circular fibers

Question 7

What happens when meridional fibers are contracted

Answer 7

ligaments are pulled forward and medially, releasing tension

Question 8

What happens when circular fibers contract

Answer 8

tension on ligaments decreases (functions like a sphincter)

Question 9

Ciliary muscles are regulated by ____ nervous system

Answer 9

parasympathetic

Question 10

Parasympathetic activity causes ciliary muscles to _____

Answer 10

contract. Lens becomes more convex, refractive power increases

Question 11

Has reflex control over pupil diameter

Answer 11

autonomic nervous system

Question 12

Symathetic activation causes pupil _____

Answer 12

pupil dilation (mydriasis)

Question 13

Parasympathetic activation causes pupil ____

Answer 13

constriction (miosis)

Question 14

Small diameter pupil results in ___ depth of focus

Answer 14

long

Question 15

Large diameter pupil results in ____ depth of focus

Answer 15

short

Question 16

When eye fixated on nearby object, three reflexes are evoked

Answer 16

1) convergence of eyes, to center object on fovea
2) accommodation to focus object
3) miosis (pupil constriction) to maximize depth of focus

Question 17

Bilateral small pupils that constrict when patient focuses on near object but do not constrict when exposed to bright light

Answer 17

Argyll Robertson pupil

Question 18

Condition strongly associated with Argyll Robertson Pupil

Answer 18

neurosyphyllis

Question 19

Eye with no visual defects

Answer 19

Emmetropia

Question 20

Hyperopia (farsightedness)

Answer 20

caused by eyeball that is too short or lens system that is too weak. Light rays are not bent enough when lens is completely relaxed

Question 21

Myopia (nearsightedness)

Answer 21

Caused by eyeball that is too long or lens system which is too strong. No way to reduce lens strength when ciliary muscle is fully relaxed.

Question 22

Light from one plane is focused at a different distance than light from a second plane

Answer 22

Astigmatism

Question 23

Why can’t a spherical lens correct for an astimatism?

Answer 23

different degrees of correction are required in different planes

Question 24

Mechanism of exchange between aqueous and vitreous humors

Answer 24

diffusion

Question 25

Which humor in the eye is free flowing liquid?

Answer 25

aqueous humor

Question 26

Which humor in the eye is gelatinous?

Answer 26

vitreous humor

Question 27

Aqueous and vitreous humors. Which is anterior?

Answer 27

aqueous humor

Question 28

Secretes the aqueous humor, which is continuously formed and reabsorbed

Answer 28

ciliary body (also called ciliary processes)

Question 29

What determines intraocular pressure

Answer 29

Balance between formation and reabsorption of aqueous humor

Question 30

Damage to the optic nerve (specifically retinal ganglion cells)

Answer 30

Glaucoma

Question 31

Typical cause of elevated intraocular pressure

Answer 31

decreased outflow of aqueous fluid

Question 32

How does elevated intraocular pressure cause glaucoma

Answer 32

pressure may compress optic nerve and cause permanent damage

Question 33

Angle-Closure (narrow angle) Glaucoma

Answer 33

Iris blocks flow of intraocular fluid (anatomical barrier). Rapid rise in intraocular pressure and damage to optic nerve

Question 34

Open Angle Glaucoma

Answer 34

Flow of introcular fluid impeded at trabecular meshwork (no anatomical barrier). More common than the other type. Slower rise in intraocular pressure.