Vision

Question 1

white part of the eye, composed of tough connective tissue.

Answer 1

Sclera

Question 2

Anteriorly to sclera, the outer layer consists of transparent

Answer 2

cornea

Question 3

contains many blood vessels which nourish the retina

Answer 3

choroid

Question 4

Choroid layer becomes specialized anteriorly to form the

Answer 4

ciliary body and iris

Question 5

contains the rods and cones, the photoreceptors that convert light energy into nerve impulses.

Answer 5

retina

Question 6

has the highest level of visual acuity (i.e. the ability to distinguish between two-point light sources.

Answer 6

fovea

Question 7

The posterior cavity between the lens and retina contains jellylike substance

Answer 7

the vitreous humor.

Question 8

The anterior cavity between cornea and lens contains a clear watery fluid, the _______ _____.
carries nutrients for the cornea and lens and is produced at a rate of about 5 ml/day by a capillary network

Answer 8

aqueous humor

Question 9

The fluid produced by aqueous humor drains into a canal of ________ at the edge of the cornea and eventually enters the blood

Answer 9

canaal of schlemm

Question 10

The condition associated with increased intraocular pressure is known as

Answer 10

glaucoma

Question 11

the second leading cause of blindness in the United States and the leading cause of blindness among African Americans

Answer 11

Glaucoma

Question 12

characterized by progressive optic neuropathy with loss of retinal neurons and the nerve fiber layer, resulting in blindness if left untreated.

Answer 12

Glaucoma

Question 13

results from rapid increases in intraocular pressure. Patients present with a painful, red eye and are at risk of rapid permanent vision loss-medical emergency.

Answer 13

Acute closed-angle glaucoma

Question 14

much more common and presents as painless progressive loss of vision. Typically, the peripheral vision is affected first and the central vision is affected later.

Answer 14

Open-angle glaucoma

Question 15

intraocular pressure is normal, but optic nerve damage and visual field loss still occur

Answer 15

Normal-tension, or low-tension glaucoma

Question 16

results from rapid increases in IOP

Answer 16

Acute closed-angle glaucoma

Question 17

The point on the retina at which the optic nerve leaves and through which blood vessels pass is the

Answer 17

optic disc

Question 18

the neural rim of the optic disc shrinks and the physiologic cup within the optic disc enlarges

Answer 18

pathologic “cupping.”

Question 19

The main goal of glaucoma therapy is to

Answer 19

lower intraocular pressure (IOP).

Question 20

treatment for glaucoma

Answer 20

Laser surgery and incisional surgery

Question 21

drugs to treat glaucoma that decrease aqueous production

Answer 21

Carbonic anhydrase inhibitors
Alpha-adrenergic agonists
Beta-adrenergic antagonists

Question 22

drugs to treat glaucoma that increase aqueous outflow

Answer 22

Prostaglandin derivatives
Cholinergic agonists
Alpha-adrenergic agonists

Question 23

Changing the shape of lens to focus an object is called __________.

Answer 23

accommodation

Question 24

a circular ring of smooth muscle attached to the lens by suspensory ligaments.

Answer 24

ciliary muscle

Question 25

In the normal eye, the ciliary muscle is relaxed and the lens is _____ for far vision. When the ciliary muscle contracts, the lens becomes more ______ and stronger for near vision.

Answer 25

flat | convex

Question 26

fibers on lens, which occasionally become opaque so that light rays cannot pass through, a condition known as

Answer 26

cataract

Question 27

how may cataract be treated

Answer 27

defective lens can usually be surgically removed and vision restored by an implanted artificial lens or compensating eyeglasses.

Question 28

With advancing age the lens becomes sclerotic and less flexible. With loss of elasticity, the lens can no longer assume the spherical shape required to accommodate for near vision. This age-related reduction is known as

Answer 28

presbyopia

Question 29

caused by uneven curvature of the cornea. | occurs in combination with nearsightedness or farsightedness.

Answer 29

Astigmatism

Question 30

Astigmatic errors can be corrected with _______ lenses, frequently in combination with ______ lenses, or with _____ ______ lenses.

Answer 30

cylindrical spherical hard contact

Question 31

During embryonic development the retinal cells _______ ______ of the nervous system, so the retinal layers are actually facing backward from the incoming light. Light must pass through several retinal layers before reaching the photoreceptors.

Answer 31

“back out”

Question 32

The point on the retina at which the optic nerve leaves and through which blood vessels pass is called the ______, , also often referred to as the blind spot

Answer 32

optic disc

Question 33

The area immediately surrounding fovea, ______ ______, also has a high concentration of cones and fairly high acuity, but less than in fovea, because of overlying ganglion and bipolar cells in the macula.

Answer 33

macula lutea

Question 34

major cause of gradual or sudden, painless, central vision loss in the elderly, brought on by deterioration of the macula.

Answer 34

Age-related Macular Degeneration (AMD)

Question 35

Age-related Macular Degeneration (AMD) occurs in two forms

Answer 35

nonexudative (dry) form and an exudative (wet) form.

Question 36

is most common type of macular degeneration and affects 90% of the people who have the condition. there is a breakdown or thinning of the layer of retinal pigment epithelial cells (RPE) in the macula.

Answer 36

Dry AMD (Age-related Macular Degeneration)

Question 37

Loss of the ________ leads to degeneration of photoreceptors resulting in loss of vision in advanced AMD.

Answer 37

pigment epithelial cells (RPE)

Question 38

treament for Dry AMD

Answer 38

There is no FDA approved treatment for dry AMD. Some evidence exists, that treatment with vitamins C and E, beta-carotene, and zinc may retard dry macular degeneration

Question 39

Abnormal blood vessel growth (angiogenesis) is a hallmark of _____. Neovascular vessels from the choroid grow underneath the RPE and leak serum and blood, damaging the macula and causing central vision loss.

Answer 39

Exudative macular degeneration (wet AMD)

Question 40

treament for wet AMD

Answer 40

Macugen and Lucentis

Question 41

a selective VEGF antagonist

Answer 41

Macugen (Pegaptanib)

Question 42

a humanized anti-VEGF antibody fragment that inhibits VEGF activity by competitively binding with VEGF.

Answer 42

Lucentis (ranibizumab)

Question 43

monochromatic (single color) receptor, which are highly sensitive to light and allow objects to be seen in low intensity light

Answer 43

Rods

Question 44

(increased light sensitivity in response to prolonged darkness) occurs to much greater extent in rods than in cones.

Answer 44

Dark adaptation

Question 45

There are three types of cone photoreceptors, with overlapping sensitivity to light of different wavelength:

Answer 45

1. Blue (or S) cones absorb light of short wavelength 2. Green (or M) cones absorb light of medium wavelength 3. Red (or L) cones absorb the light at the long wavelength.

Question 46

properties of cones (6)

Answer 46

``` color vision low sensitivity day vision concentrated in fovea 3 mil per retina high acuity ```

Question 47

properties of rods (6)

Answer 47

``` 100 million per retina Vision in shades of gray High sensitivity Low acuity Night vision More numerous in periphery ```

Question 48

deficiency of vitamin A

Answer 48

results in night blindness (rod cell dysfunction)

Question 49

xerophthalmia

Answer 49

dry eyes that are prone to ulceration and infection

Question 50

follicular hyperkeratosis

Answer 50

rough elevations of skin around hair follicles resembling goose bumps

Question 51

common condition in which there is a range of possible defects in color vision.

Answer 51

Color blindness

Question 52

common cause of color blindness

Answer 52

X-linked recessive mutations are a common cause of defective color vision, resulting in a higher proportion of males than females with this condition

Question 53

The pupillary constrictor fibers release _______, which activates muscarinic AChRs. Sympathetic pupillary fibers release norepinephrine, which activates a1-adrenergic receptors.

Answer 53

acetylcholine

Question 54

Drugs that inhibit ________, or that stimulate a1-adrenergic receptors, dilate the pupils, whereas drugs that stimulate _________ or block a1-adrenergic receptors cause pupillary constriction.

Answer 54

mAChRs | mAChRs

Question 55

Used as miotics | (to constrict pupil) for control of intraocular pressure in glaucoma

Answer 55

Parasympathomimetics

Question 56

Cholinergic agonists of Parasympathomimetics

Answer 56

Cholinergic agonists: pilocarine, carbachol, methacholine

Question 57

Used as mydriatics (to dilate pupil) to aid in eye examination or as cycloplegics (to relax ciliary muscles)

Answer 57

Parasympatholitics

Question 58

Parasympatholitics Anticholinergic agents

Answer 58

Mydriatic: eucatropine

Question 59

Cyctoplegic and mydriatic drugs

Answer 59

homatropine, scopolamine, atropine, cyclopentolate

Question 60

Sympathomimetics

Answer 60

Used for mydriasis; do not cause cycloplegia

Question 61

Sympathomimetics drugs

Answer 61

Phenylephrine, hydroxyamphetamine,epinephrine, cocaine

Question 62

Lateral geniculate nucleus

Answer 62

in the thalamus separates information received from the eyes and relays it via optic radiation to different zones in the cortex

Question 63

Damage of visual cortex of one side will produce the loss of visual field on the opposite side to the lesion. Occipital hematoma produce _______ _______ and headache

Answer 63

homonymous hemianopia

Question 64

The overlapping area seen by both eyes at the same time is known as the ________, which is important for depth perception.

Answer 64

binocular (“two-eyed”) field of vision

Question 65

amblyopia

Answer 65

misaligned eyes

Question 66

diplopia

Answer 66

double vision

Question 67

Drugs that possess anticholinergic properties that are known to induce visual disturbances.

Answer 67

Antihistamines antipsychotics tricyclic antidepressants