OPHTHALMOLOGY: 476-479 Flashcards

1
Q

What type of vision impairments improve with glasses?

A

Refractive errors

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2
Q

What are 4 types of refractive errors?

A
  1. Hyperopia
  2. Myopia
  3. Astigmatism
  4. Presbyopia
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3
Q

What is hyperopia?

A

Eye too short for refractive power of cornea and lens - light ends up being focused behind the retina

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4
Q

What is myopia?

A

Eye too long for refractive power of cornea and lens - light ends up being focused in front of the retina

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5
Q

In a patient with astigmatism, why is the refractive power different at different axes?

A

Abnormal curvature of the cornea

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6
Q

Why is there a decrease in focusing ability during accommodation in presbyopia?

A

Sclerosis and decreased elasticity

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7
Q

Name the 2 structures inflamed in uveitis and 2 accompanying symptoms.

A

2 structures: anterior uvea and iris

2 symptoms: hypopyon (sterile pus) and conjunctival redness

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8
Q

What does long term retinitis lead to?

A

Scarring (from retinal edema and necrosis)

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9
Q

Name 3 common causes of retinitis.

A

Viral - CMV, HSV, HZV

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10
Q

What type of patient is more likely to get retinitis?

A

Immunosuppressed

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11
Q

On physical exam, you notice that a patient has a cloudy retina with attenuated vessels and a “cherry-red” spot at the fovea. What is your diagnosis?

A

Central retinal artery occlusion

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12
Q

How does central retinal artery occlusion present?

A

Acute, painless monocular vision loss

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13
Q

What is retinal vein occlusion usually secondary to?

A

Blockage of the central or branch retinal vein is often secondary to compression from nearby arterial atherosclerosis

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14
Q

What 2 things are typically observed in retinal vein occlusion in the affected area?

A

Retinal hemorrhage and edema

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15
Q

What are the 2 types of diabetic retinopathy?

A

Proliferative and non-proliferative

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16
Q

What metabolic imbalance causes diabetic retinopathy?

A

Chronic hyperglycemia

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17
Q

Describe what happens in non-proliferative diabetic retinopathy.

A

Damaged capillaries leak blood –> lipids and fluid seep into retina –> hemorrhages and macular edema

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18
Q

What is the treatment for non-proliferative diabetic retinopathy?

A

Blood sugar control, macular laser

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19
Q

What proliferates in proliferative diabetic retinopathy and why?

A

New blood vessel formation due to chronic hypoxia. This leads to traction on the retina.

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20
Q

What is the treatment for proliferative diabetic retinopathy?

A

Peripheral retinal photocoagulation, anti-VEGF injections

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21
Q

Describe the flow of aqueous humor.

A
  1. Synthesized by the ciliary epithelium on the ciliary muscle
  2. Secreted into the posterior chamber
  3. Flows between the front of the lens and the back of the iris into the anterior chamber
  4. Drains out of the eye via trabecular meshwork into the Canal of Schlemm
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22
Q

What is the definition of glaucoma and what are 2 common symptoms?

A

Optic disk atrophy with characteristic cupping often presenting with:

  1. Increased intraocular pressure
  2. Progressive peripheral visual field loss
23
Q

What are the two types of glaucoma?

A

Open angle and closed/narrow angle

24
Q

Is open angle painful?

A

No - Painless

25
In what kind of patients is open angle glaucoma more common in?
Older, African-American, family history, more common in the U.S.
26
What is the cause of primary open angle glaucoma?
Unclear
27
Name the major problem in secondary open angle glaucoma and 3 potential causes.
Blocked trabecular meshwork from any of the following: 1. WBC's (e.g. uveitis) 2. RBC's (e.g. vitreous hemorrhage) 3. Retinal elements (e.g. retinal detachment)
28
Describe the pathogenesis in primary closed/narrow angle glaucoma.
Enlargement or forward movement of the lens against the central iris leads to obstruction of normal aqueous flow through the pupil --> fluid builds up behind the iris --> peripheral iris pushes against the cornea --> impedes flow through the trabecular meshwork
29
What is the major problem in secondary closed/narrow angle glaucoma?
Hypoxia from retinal disease (e.g. diabetes, vein occlusion) induces vasoproliferation in the iris causing contraction of the angle --> impaired flow
30
Compare and contrast acute vs. chronic closure in closed/narrow angle glaucoma.
Chronic - often asymptomatic with damage to optic nerve and peripheral vision Acute - EMERGENCY, very painful, sudden vision loss, halos around lights, rock-hard eye, frontal headache
31
What drives acute closure in closed angle glaucoma?
Increased intraocular pressure pushes the iris forward and closes the angle abruptly
32
What is contraindicated in acute closure in closed angle glaucoma? Why?
Epinephrine because of its mydriatic effect
33
What is a cataract?
Painless opacification of the lens
34
Are cataracts often unilateral or bilateral?
Bilateral
35
What are some risk factors for cataracts?
``` CATARACTS: Cigarette Age (older) Trauma Alcohol ``` Rare genetic metabolic disorders (classic galactosemia, galactokinase deficiency) Autosomal recessive Corticosteroids Tanning (excessive sunlight) Sorbitol or sugar (diabetes)
36
Is papilledema usually unilateral or bilateral?
Bilateral
37
What is papilledema?
Optic disc swelling due to increased intracranial pressure
38
On fundoscopic exam, what is observed with papilledema?
Enlarged blind spot and elevated optic disc with blurred margins
39
Which cranial nerve innervates the lateral rectus?
CN VI
40
Which cranial nerve innervates the superior oblique?
CN IV
41
What does CN III innervate?
Superior rectus, inferior rectus, medial rectus, inferior oblique
42
Patient's eye looks down and out. Which cranial nerve is damaged and what else do you expect to see?
CN III Also expect ptosis, pupillary dilation, loss of accomodation
43
What happens if you damage CN VI?
Medially directed eye that cannot abduct
44
What three motions does the superior oblique mediate?
Abduction, intorsion, depression
45
If CN IV is damaged, what does the eye do?
Eye moves upward, particularly with contralateral gaze and head tilt toward the side of the lesion
46
Do the obliques move the eye in the same or opposite direction as their name suggests?
Opposite
47
Describe the pathway of light through the eye.
Cornea --> aqueous humor (anterior chamber) --> iris --> pupil --> lens --> vitreous chamber --> retina --> optic nerve
48
Where is vision the sharpest?
At the fovea centralis in the center of the macula
49
Where is the blind spot?
At the optic disc, where the nerve joins the retina
50
What are the three layers of the eye that go all the way around?
Sclera - white of the eye Choroid - vascular layer Retina - contain the receptors for vision
51
What bends the light so it reaches the macula?
Lens
52
What is the purpose of the ciliary body?
Controls the lens
53
Which structure controls the size of the pupil?
Iris