Corneal Function Flashcards Preview

Ocular Physiology > Corneal Function > Flashcards

Flashcards in Corneal Function Deck (22):
1

How does the cornea refract light?

curvature of ant and post surface
change in refractive index
corneal thickness

2

Power of Cornea

40-48
43

3

Maximizing Corneal Light Transmission

smooth optical surface / tear film
regularity of epithelial cells
no blood vessels
correct arrangement of collagen in stroma
<1% light scatter

4

Corneal Protective Functions

blink away microbes = decrease infections
prevent retinal damage by blocking UV and penetrating injuries
fast healer

5

Normal CV of Endothelium

0.25

6

Normal Endothelial Cell Density

2000 cells/mm2

7

Hexagonality of Endothelial Cells

69%

8

Size of Stromal Collagen Fibrils

300A

9

Spacing between Stromal Collagen Fibrils

550A

10

Stroma should consist of ________% water

75 - 80

11

Dua's Layer can withstand up to _______ pressure

200 kPa

12

Epithelium has ______ that help maintain hydration

tight junctions

13

Stroma uses ________ to pull water in

anionic proteoglycans

14

Endothelium plays what role in hydrating the cornea?

leaks fluids

15

Corneal Hydration is dependent on...

barrier function of epithelium and endothelium
water and ion transport through epi and endo membranes
anionic characteristics of materials in stromal matrix

16

Pressures of 50 mmHg has what effect?

moves extra water into stroma from ant chamber, which overwhelms the endothelial transport system

17

Corneal abrasions can break the barriers of....

zonular occludens
causes edema/ haziness

18

Allows the cornea to heal so rapidly

peptide growth factors

19

Corneal Ulcer

infectious condition that compromises that integrity of the epithelium

20

Hydrophobic/ nonpolar parts of cornea

epithelium and endothelium

21

Hydrophilic/ polar part of cornea

stroma
sucks water in

22

Is the epithelium permeable to ions?

no