Cornea (M2) Flashcards Preview

II. Anterior Segment Disease > Cornea (M2) > Flashcards

Flashcards in Cornea (M2) Deck (64)
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1

What are the layers of the cornea?

1. epithelium
2. Bowman's layer
3. Stroma
4. Descemet's membrane
5. edothelium

2

What percentage of the corneal thickness is stroma?

90%

3

What percentage of the refractive power of the eye is due to the cornea?

75%

4

What is the average thickness of the cornea?

540 microns

5

How long does it take to heal the Bowman's membrane?

6 weeks

6

What layer of the cornea holds mucin and keeps the cornea hydrated?

glycocalyx layer (Slime layer)

7

What hold the basal corneal cells together?

zonal occludens

8

What holds the basal corneal cells to the basement membrane?

hemidesmosomes

9

How many cells/mm does a normal adult endothelium have? 1. At what number of cells does edema occur? 2

1. 3,000
2. 500 cells/mm

10

What are the gram positive bacteria that make up the normal flora of the cornea?

1. Staph. aureus (common)
2. Staph. epidermidis (common)
3. Diphtheroids
4. Propionibacterium acnes
5. Strep. pneumonia
6. Strep. viridans

11

What are the gram negative bacteria that make up the normal flora of the cornea?

1. E. coli
2. Klebsiella
3. Proteus
4. Moraxella
5. Pseudomonas (rare)
6. Haempjilus influenzae (rare)

12

What are the fungi that make up the normal flora of the cornea?

candida (less common)

13

What is the enzyme on the cornea that breaks down bacterial cell walls?

lysozymes

14

What is the metal chelating protein found on the cornea?

lactoferrin

15

What is the antibody the prevents bacterial adherence on the cornea?

IgA

16

What are the risk factors for microbial keratitis?

1. CL wearer
2. Trauma
3. topical corticosteroids
4. chronic corneal surface disease
5. ocular surgery
6. ocular adnexal conditions
7. systemic disease
8. smoking

17

What are the bacteria capable of corneal penetration without epithelial compromise?

1. Neisseria gonorrhea
2. Neisseria meningitidis
3. Hemophilus influenzae
4. Corynebacteria diphtheria

18

What is required for the infection to be an infectious corneal ulcer?

1. eroded epithelium
2. underlying stromal infiltrate

19

What are the proper times to culture a kerititis?

1. non-responsive lesion
2. extensive infiltration of cornea
3. lesion >1.0mm that is central or paracentral
4. post-surgical infection
5. monocular patient
6. immunocompromised patient

20

What does the prescription abbreviation "ad lib." mean?

freely, as needed

21

What does the prescription abbreviation "a.c." mean?

before meals

22

What does the prescription abbreviation "b.i.d." mean?

twice a day capsule

23

What does the prescription abbreviation "gtt." mean?

drops

24

What does the prescription abbreviation "h.s." mean?

at bedtime

25

What does the prescription abbreviation "p.c." mean?

after meals

26

What does the prescription abbreviation "p.o." mean?

by mouth

27

What does the prescription abbreviation "p.r.n." mean?

as needed

28

What does the prescription abbreviation "oint" mean?

ointment

29

What does the prescription abbreviation "qAM" mean?

every morning

30

What does the prescription abbreviation "q.4.h." mean?

every four hours