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Clinical Med B > intro to eyeballs > Flashcards

intro to eyeballs Flashcards

1
Q

What is the macula

A

The pigmented part of the retina located in the very center.

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2
Q

what is the fovea

A

The fovea is the area of best visual acuity. It contains a large amount of cones—nerve cells that are photoreceptors with high acuity.

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3
Q

What is the order of the parts of the eye that light shines through when we see things

A

light reflects off of objects and goes through:
1. cornea
2. iris
3. pupil
4. lens
5. retina
6. optic nerve carries those light signals to brain.

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4
Q

what does hyperopia cause

A

farsightedness (nearby objects look blurry)

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5
Q

what part of the eye is where light actually enters the eye

A

the pupil

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6
Q

what is the job of the lense of the eye

A

to focus the light entering the eye by bending/flattening/changing shape to focus the light rays

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7
Q

What are the parts of the eye that are in charge of changing the shape of the lense

A

ciliary body/ciliary muscles
suspensory ligaments

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8
Q

How would the lense shape change in order to see an object that is near to you.

A
  1. ciliary muscles contract
  2. suspensory ligaments slacken
  3. lens becomes thicker
  4. light focuses on retina
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9
Q

How would the lense shape change in order to see an object that is far away from you.

A
  1. ciliary muscles relax
  2. suspensory ligaments become taut
  3. lens becomes thinner
  4. light focuses on retina
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10
Q

what happens to the focal length of the lens when looking at a close by object

A

focal length of the lens decreases

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11
Q

what happens to the focal length of the lens when looking at a far away object

A

focal length of the lens increases

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12
Q

What causes hyperopia

A

too little curvature of the cornea due to the eyeball being too short for the refractive power of the cornea and lens

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13
Q

What is the focal point

A

where light focuses precisely on the retina.

For good vision, the focal point must be on the retina

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14
Q

What is refraction

A

the process of bending light to produce a focused image on the retina.

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15
Q

why do most vision problems occur

A

because of an error in how our eyes REFRACT light

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16
Q

when do refraction errors occur

A

when the shape of your eye keeps light from focusing correctly on your retina

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17
Q

What are the types of errors of refraction

A

myopia
hyperopia
astigmatism
presbyopia
keratoconus

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18
Q

what causes myopia

A

too much curvature of the cornea due to the eyeball being too long for the refractive power of the cornea and lens.

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19
Q

What is the result of myopia

A

nearsightedness (trouble seeing distant objects)

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20
Q

where is the focal point in someone with myopia

A

in front of the retina

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21
Q

how is myopia corrected

A

with a concave lens

“Wide view lens, diverges light rays, makes objects look smaller than they are” idk what any of this means

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21
Q

where is the focal point in people who have hyperopia

A

light is focused behind the retina

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21
Q

how do you correct hyperopia

A

with a convex

“The rays meet at a single point on other side of lens
Magnify objects to make them look larger”

“Such lenses are used to focus a beam of light on making the object look clearer and larger.”

again, not sure what this means but im sure its important

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22
Q

describe the effect of a concave lens

A
  1. Spreads out light rays
    diverging
  2. Focal point in front of lens
  3. Parallel rays of light pass through the lens are spread out
  4. Image formed is smaller but clear
  5. Gives wider viewing angle
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23
Q

Describe the effects of a convex lense

A
  1. Focuses the light rays to a specific point
  2. Convergent
  3. Rays of light passing through it get bent in a inward direction towards a single point
  4. Brings light rays together to a focal point behind the lens
  5. Convex lenses hold magnifying abilities
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24
Q

what causes astigmatism

A

irregular shape of the cornea or lens (its not perfectly spherical, kinda like a football)

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25
Q

where is the focal point in someone with astigmatism

A

light reflected into multiple areas of the eye = multiple focal points

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26
Q

how does astigmatism affect vision, how is it corrected

A

retinal image to be blurred, corrected with cylindrical lenses that equalize the refraction of light

aka causes this picture

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27
Q

how is astigmatism corrected

A

with cylindrical lenses that equalize the refraction of light

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28
Q

what causes presbyopia

A

age related farsightedness that leads to loss of mobility and focusing power of the lense

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29
Q

how is presbyopia primarily initially noticed

A

usually by the inability to read small print around 44-46 years old, symptoms increase until about age 55 and then stabilize

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30
Q

how is presbyopia corrected

A

reading glasses.

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31
Q

What causes keratoconus

A

cornea becomes thin and conelike, etiology is unknown but it usually developes in puberty or early adulthood.

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32
Q

who is keratoconus most common in

A

people with a hx of corrective lenses, contact lenses, and cornea transplants.

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33
Q

what does keratoconus cause

A

blurred vision and sensitivity to light and glare

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34
Q

How is keratoconus corrected

A

it is chronic and progressive…… unsure of how its corrected tbh

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35
Q

What are the photoreceptors of the retina

A

rods and cones

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36
Q

what are rods specialized for

A

dim light (night vision)

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37
Q

what are cones specialized for

A

color perception (red, green and blue cones)

color blindness results from deficit of one type of cone.

38
Q

what is the aqueous humor

A

the anterior cavity between cornea and lens

39
Q

where is the aqueous humor produced

A

the ciliary body

40
Q

what is the job of the aqueous humor

A
  1. supplies nutrients to cornea and lens because cornea and lens do NOT have blood vessels.
  2. maintains intraocular pressure!
41
Q

What is the vitreous humor

A

the posterior cavity between lens and retina that is filled with a jelly like substance to maintain the shape of the eyeball and hold the retina in place

42
Q

What is glaucoma

A

a group of eye diseases characterized by neuropathy of the optic nerve. this is caused by cupping of the optic disk on ophthalmologic examination

I think its technically caused by build up of aqueous humor fluid which leads to increased pressure and damage to the optic nerve. see pic.

43
Q

what causes glaucoma

A

cupping of the optic disk on ophthalmologic examination

44
Q

what is the FIRST leading cause of blindness

A

cataracts

45
Q

what is the SECOND leading cause of blindness

A

glaucoma

46
Q

what is the difference between narrow angle glaucoma and open angle glaucoma

A

narrow angle is acute angle closure, aka it happens suddenly

open angle is chronic glaucoma, aka it occurs slowly.

this was not on the slides, i googled this. it just helps me to remember that narrow angle is ACUTE and open angle is CHRONIC

47
Q

draw out visual fields…. pic is on the other side of this card.

A

okie dokie

48
Q

what controls pupillary contriction

A

the PNS

49
Q

what controls pupillary dilation

A

the SNS

50
Q

what muscles control pupillary constriction and dilation

A

the sphincter and dilator pupillae muscles (circular group of muscles surrounding iris)

51
Q

How do you examine pupillary reaction

A
  1. have patient focus on far object, not your light
  2. observe pupillary reaction bilaterally
    (when light is shone into eye and when light is moved away)
  3. note direct and consensual reaction (magnitude, speed and symmetry)
52
Q

what is RAPD

A

relative afferent pupillary defect - Marcus Gunn Pupil

normal consensual response but no direct response.

explanation: If an optic nerve lesion is present, the affected pupil will not constrict to light when light shone in that pupil. It will constrict, however, when light shone into other eye (consensual)

53
Q

what test is needed when a relative afferent pupillary defect (RAPD) is suspected

A

the swinging eye flashlight test

54
Q

what is anisocoria

A

asymmetric size of the pupils. The pupils have no or sluggish pupillary reaction to light.

55
Q

what are the possible causes of amisocoria

A

may be a normal variant (20%) such as horners syndrome or adies syndrome.

could be pathologic (80% i assume) caused by lesion, tumor ect.

56
Q

What is horner’s syndrome

A

categorized by a loss of sympathetic innervation which causes the PAM horner triad:
* ptosis
* anhidrosis
* miosis

57
Q

what is the cause of horners syndrome

A

caused by a lesion along the sympathetic pathway.

58
Q

When is horners syndrome typically found

A

infants and children.
suspect is increased if there is associated heterochromia.

59
Q

what is adies pupil?

A

also known as tonic pupil

Categorized by pupillary reaction to light that is either absent or sluggish. This occurs with both direct and consensual.

60
Q

what is commonly associated with Adies syndrome?

A

diminished DTR’s aka Holmes-Adie’s syndrome

61
Q

what population is Adie’s syndrome most common in

A

common in women in 3rd/4th decade of life (30s-40s)

62
Q

what ophthalmic disorder is a hallmark of tertiary syphilis

A

Argyll-Robertson Pupil

63
Q

what is Argyll-Robertson Pupil

A

Pupils restrict to accommodation, but not light
Usually bilateral

so like they DO dilate/constrict to seeing things close up/far away but they do NOT dilate/constrict in response to light.

64
Q

What are cataracts categorized by

A

loss of transparency of the lens, leading to blurred vision and the absence of the red reflex.

These are generally painless.

65
Q

what is the fovea important for

A

Necessary for sharp, central vision
Reading, driving, any activity where visual details are needed
Provides greatest visual acuity of all

66
Q

what is the macula important for

A

Functional center of the retina
Responsible for the central, high-resolution, color vision that is possible in good light
In your direct line of sight

67
Q

what are some abnormalities that could be found on a fundoscopic exam

A

Retinal Detachment
Papilledema
Cotton Wool Spots
A-V Nicking
Boxcar Segmentation
Cherry Red Spot
Cupping
Flame Hemorrhages
Hard Exudates
Retinal Drusen

68
Q

What do cotton wool spots aka soft exudates look like and what causes them

A

Small, yellow-white, slightly elevated lesions, which look like clouds on retinal surface
d/t interruption of blood flow with occlusion of precapillary blood flow, microischemia

69
Q

what is the most common cause of cotton wool spots aka soft exudates

A

diabetic retinopathy and hypertensive retinopathy

70
Q

what is retinal detachment

A

when the retina at the back of the eye pulls away from its normal position

definition from google cuz slide literally said nothing.

71
Q

what is papilledema

A

swelling of the optic nerve

72
Q

what is papilledema categorized by

A
  1. disc elevation
  2. venous distention and tortuosity
  3. obscuration of normal disc margin an overlying retinal vessels.
  4. absence of spontaneous venous pulsations.
73
Q

what is retinal vein occlusion

A

widespread retinal hemorrhages that cause venous dilation and tortuosity.

74
Q

what is central retinal artery occlusion

A

cherry red spot on the fovea with “boxcar segmentation” which is segmental blood flow

75
Q

what is AV nicking

A

a small artery seen crossing a small vein which causes compression on the small vein.
this is due to indentation (nicking) of the retinal vein by a stiff (arteriosclerotic) retinal arteries

76
Q

what is the most common cause of AV nicking

A

hypertensive retinopathy

77
Q

what is copper and silver wiring

A

vascular hyperplasia caused by atherosclerotic vessel wall thickening and chronic hypertension

78
Q

how does copper wiring present and what is it indicative of

A

indicative of moderate vascular wall changes that appear orange or yellow instead of red

79
Q

how does silver wiring present and what is it indicative of

A

indicative of severe vascular wall hyperplasia and thickening that appears white instead of red.

80
Q

where is copper and silver wiring seen

A

in hypertensive retinopathy

81
Q

what is the cup

A

the center of the optic disc

82
Q

what occurs when the optic nerve is damaged, such as in glaucoma? how does this affect the cup?

A

the nerve fibers fibers to the optic disc die off and blood flow is diminished. This causes the cup to become larger since the support structure is not there.

83
Q

what do hard exudates look like in the eye

A

smallish, yellowish-whitish distinct spots with sharp borders

84
Q

what causes hard exudates? what is the MC etiology that causes this.

A

MC etiology = diabetic retinopathy

Caused by breakdown of blood-retina border, allowing leakage from retinal vessels

This vascular permeability allows the leakage of fluid and lipoprotein into the retina

85
Q

what is the MC etiology of flame hemorrhages

A

diabetic and hypertensive retinopathy

86
Q

what occurs with flame hemorrhages.

A

When necrotic vessels bleed into the nerve fiber layer
More superficial layers of the retina

these are large

87
Q

What are dot blot hemorrhages and how do they occur

A

Occur as microaneurysms rupture in the deeper layers of the retina
Blood accumulates in the inner nuclear layer

88
Q

what occurs during neovascularization

A

Microvascular damage and ischemia cause release of vasoproliferative factors (Vascular Endothelial growth Factor)

This results in new vessel from the adjacent retinal vessels in an attempt to revascularize the diseased tissue

89
Q

what is the MC etiology of neovascularization

A

diabetic retinopathy and macular degeneration

90
Q

what is the appearance and cause of retinal drusen.

A

Yellow deposits under the retina
Made up of lipids and proteins
Scattered around macular region
“Tombstones” of dead retinal epithelium

91
Q

where does retinal drusen occur

A

Appear in a layer of the retina called Bruch’s membrane

92
Q

what is the MC etiology of retinal drusen

A

age related macular degeneration

93
Q

what is a slit lamp examination used for

A

to look at structures in the anterior chamber of the eye including:
lids, lashes, conjunctiva, cornea, anterior chamber, iris, and lens

94
Q

what is fluorescein staining used for

A

looks for corneal abrasions, ulcers, foreign bodies.

Clinical Med B (22 decks)

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